Frequently Asked Questions and Information
Frequently Asked QuestionsThe General Questions, Questions related to ordering data, and Troubleshooting Information are not project specific, but are related to the web site as a whole. The Project Information section currently contains specific questions and information for CALIPSO, CERES, ERBE, ISCCP, MISR, MOPITT, SRB, SSE, and TES. Other project information will be added.
The availability of new data sets is dependent upon a number of factors, many of which are not under our direct control. This makes it difficult to give exact release dates for specific data sets. However, we would be happy to notify you when the item you desire does become available for distribution.
Please visit the Science Directorate Educational Resources page for information on videos, classroom projects, and activities that are available for all grade levels. Trading cards, bookmarks, and lesson plans can also be downloaded from this site.
Here are the instructions:
- On the eosweb home page select "Help and Resources"
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** You should receive an email to confirm your decision to subscribe. **
Here are the instructions:
- On the eosweb home page select "Help and Resources"
- Select "Mailing List Registration"
- Select the project name
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** You should receive an email to confirm your decision to unsubscribe. **
The Order Data page provides information for accessing the ordering systems available for the Atmospheric Science Langley Data Center data.
Additionally, landing pages for each product include an “Order Data” button that, when selected, will redirect you to the most appropriate place for downloading data.
To access documentation, locate and select the link from the Projects Supported page for the project that you would like additional documentation. From the project page, locate and select the grey tab that says “documentation,” (it is the grey tab, typically located in the middle of the page). If the documentation is product specific, continue to navigate to the specific product landing page where you can access it if it is available, note that a missing tab on the product page indicates that there is no documentation specific to that product.
If available, read software can be downloaded from the respective project or product-landing page. Simply locate and select the project link from the Projects Supported page for the project that you would like to receive read software. If read software is available at the project level, from the project page, locate and select the grey tab that says, “read software” (it is the grey tab, typically located in the middle of the page). If read software is product specific, the tab will direct you to the product landing page where you can access it if it is available, note that a missing tab on the product page indicates that there is no software specific to that product.
Please note that the minimum browser requirements for the ASDC Web Ordering Tool are as follows:
- Internet Explorer 4.0
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You will be unable to access the ASDC Web Ordering Tool if your browser does not meet the minimum requirements.
If your browser meets the minimum requirements listed above and you experience problems accessing the Langley Web Ordering Tool, or have difficulty ordering data from the tool, please contact User Services for assistance. If you receive an error message, write it down and include the error message in your communication with User Services.
If you experience problems accessing Reverb, or have difficulty ordering data from the tool, please contact User Services for assistance. If you receive an error message, write it down and include the error message in your communication with User Services.
For most of the data we archive, we also provide read software. If you were unable to receive the read software with your order, select the project name on the Projects Supported page. You will be taken to the appropriate project table, where you can download the read software.
If you have tried using the read software and are still experiencing problems, please have the following information ready when you contact User Services to allow us to assist you more effectively:
Computer Architecture/Operating System Information:
- What model of computer are you using?
- What chip drives the motherboard?
- What operating system is in use?
- What version of the operating system are you using?
- Which window manager are you using?
- Which version of the window manager?
- Which C/Fortran compiler(s) are you using?
- Which version of the compiler are you using?
- Which version of HDF is installed?
- Which viewer are you using?
- Which version of the viewer are you using?
The Clouds and the Earth's Radiant Energy System (CERES) experiment provides radiometric measurements of the Earth's atmosphere from three broadband channels and is a follow-on to the Earth Radiation Budget Experiment (ERBE) mission. CERES products include both solar-reflected and Earth-emitted radiation from the top of the atmosphere to the Earth's surface. The CERES experiment will lead to a better understanding of the role of clouds and the energy cycle in global climate change.
|PFM||November 27, 1997 as part of the Tropical Rainfall Measuring Mission (TRMM) and was the first CERES instrument.|
|FM1 & FM2||December 18, 1999 into polar orbit on board the EOS flagship Terra.|
|FM3 & FM4||May 4, 2002 on board EOS Aqua.|
|FM5||October 28, 2011 on board Suomi National Polar-orbiting Partnership (NPP) satellite.|
|Access CERES Instrument specifications and Operation scan modes by month.|
Top-of-the-Atmosphere (TOA) is a surface approximately 20 km above the Earth's surface.
The TOA is an ellipsoid x²/a² + y²/a² + z²/b² = 1
where a = 6408.1370 km and b = 6386.6517 km.
Flux - is an energy flow through a unit area over a unit time; hence the units of W m-2. As radiation interacts with matter at all atmospheric layers and surfaces, measuring, understanding, and modeling the spatial, temporal and spectral distribution of fluxes is important. Flux characterizes our climate and is represented as Up, Down, Net, TOA & Surface.
Given the vertical layered structure of Earth atmosphere above underlying surfaces, the vertical variability of these fluxes is of particular interest. Hence the term "Up" and "Down" for characterizing the direction of flow of radiative fluxes at a particular level. Moreover, by counting in or out these "Up" and "Down" energy fluxes, one can define a "Net" flux that is ultimately responsible for the net energy loss or gain within any two such layers. This concept is important in defining the radiative heating or cooling of each atmospheric/surface element.
The-Top-of-Atmosphere (TOA) layers are where the first interaction occurs as the radiation from the Sun reaches Earth and then the various atmospheric layers containing gases, clouds, aerosols, and/or other constituents before finally reaching the Surface. Solar radiation is scattered and/or absorbed in each of these material layers while the atmospheric and surface constituents emit their own share of radiation. Shortwave (SW) and Longwave (LW) are the two primary spectral parts the energetics can be split into and may be further divided into finer spectral intervals depending on the specifics of the physical processes under investigation.
|Total||0.3 - 100.0 microns|
|Shortwave||0.3 - 5.0 microns|
|Longwave||8.0 - 12.0 microns|
Aqua has a 1:30 PM equator crossing time.
Terra has a 10:30 AM equator crossing time.
The CERES Field of View (FOV) is synonymous with the term Footprint and is determined by the Point Spread Function (PSF) which is a two-dimensional, bell-shaped function that defines the CERES instrument response to the viewed radiation field. The resolution of the CERES radiometers is usually referenced to the optical FOV which is 1.3° in the along-track direction and 2.6° in the cross-track direction. The CERES FOV or footprint size is referenced to an oval area that represents approximately 95% of the PSF response. Since the PSF is defined in angular space at the instrument, the CERES FOV is a constant in angular space, but grows in surface area from a minimum at nadir to a larger area at shallow viewing angles.
All-Sky scene, also known as total, is determined from all CERES footprints (20 km nominal resolution) within the given temporal or spatial domain.
Clear-Sky scene has different algorithms depending on the product ERBE-like, Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF), or Energy Balanced and Filled (EBAF). ERBE-like clear-sky scene is determined from CERES footprints that were crudely identified as clear using the ERBE scene id algorithm which uses climatological, zonal LW thresholds and appropriate SW thresholds based on 12 scene ids.
EBAF & SSF clear-sky scenes are determined from CERES footprints that are 99% clear as identified by CERES-MODIS clear-sky mask from the MODIS pixels contained within the CERES footprint. SSF clear-sky products contain many cloudy regions that may have no clear-sky observations for one particular month with no attempts to fill these regions. The EBAF clear-sky products filled all non-observed clear-sky regional fluxes for a complete clear-sky global map, and all temporal and spatial domains should have clear-sky fluxes.
The NPP platform carries the FM5 instrument, which operates in the fixed azimuth scanning mode though it can operate in a rotating azimuth scanning mode. The Terra and Aqua satellites carry two CERES instruments onboard, one in Cross-Track mode and the other in Rotating Azimuth Plane Scan (RAPS) mode or in Fixed Azimuth Plane Scan (FAPS) mode. The first CERES instrument PFM, launched in November 1997 as part of the TRMM mission, was powered off May 29, 2001.
Fixed Azimuth Plane Scanning (FAPS) has scan lines perpendicular to the path of the satellite, while Rotating Azimuth Plane Scan (RAPS) lines are at a wide range of angles with respect to the satellite's path. An instrument operating in RAPS has increased spectral darkening of the transmissive optics. The Cross-Track instrument is recommended by CERES, since the spatial distribution of footprints is uniform.
CERES is a global data set whose satellite orbit determines the spatial coverage at the surface.
|Satellites||Instruments||MinLat||MaxLat||MinLon||MaxLon||Spatial Altitude||Temporal Range|
|NPP||FM5||-90||90||-180||180||824 km||Feb 2012 - present|
|Aqua||FM3 & FM4||-90||90||-180||180||705 km||Jun 2002 - present|
|Terra||FM1 & FM2||-90||90||-180||180||705 km||Feb 2000 - present|
Dec 1997 - Sep 1, 1998
*occasional coverage for coincident overflights with Terra in 1999 - 2001
|1 byte integer||127|
|2 byte integer||32767|
|4 byte integer||2147483647|
|4 byte real||3.402823E+38|
|8 byte real||1.7976931E+38|
|Surf Index||CERES Surface Type|
|1||Evergreen Needle Forest|
|2||Evergreen Broadleaf Forest|
|3||Deciduous Needle Forest|
|4||Deciduous Broadleaf Forest|
Access the full parameter list and temporal coverage of available data sets by selecting each individual product on the CERES Data and Information page..
|BDS||Filtered Radiances, Detector Values, Instr. Engineering Parameters|
|CERES-NEWS-CCCM||TOA Flux, Surface (Radiative) Flux, OLR, Surface Types, Aerosol Optical Thickness, Cloud Base Height, Cloud Top Height, Cloud Optical Depth, Aerosol Extinction Coefficient, Aerosol Base Height, Aerosol Top Height, Cloud Extinction Coefficient, Cloud Vertical Profile, Radar-only Liquid Water Content, Radar-only Liquid Ice Content, Vertical Flux Profile, Unfiltered Radiances, Filtered Radiances.|
|CRS||Cloud Properties, TOA Fluxes, Surface (Radiative) Fluxes, Unfiltered Radiances, Surface Types|
|EBAF||Clear-sky and All-sky TOA Adjusted Fluxes|
|ES-4||Clear-sky and Total-sky Fluxes, Clear-sky and Total-sky Solar Incidence, Clear-sky and Total-sky Albedo|
|ES-8||TOA Fluxes, Unfiltered Radiances, Filtered Radiances, OLR, ERBE Scene Identification|
|ES-9||Clear-sky and Total-sky Fluxes, Clear-sky and Total-sky Solar Incidence, Clear-sky and Total-sky Albedo|
|FSW||Clear-sky and All-sky TOA Fluxes, Surface (Radiative) Fluxes, OLR, Clear-sky and All-sky Albedo, Cloud Properties, Surface Types|
|ISCCP-D2like||Cloud fraction, Effective Pressure, Temperature, optical depth, IWP/LWP, particle size, IR Emissivity in PC/Tau bins similar to ISCCP-D2 product|
|SFC||Clear-sky and All-sky TOA Fluxes, Surface (Radiative) Fluxes, OLR, Clear-sky and All-sky Albedo, Cloud Properties, Surface Types|
|SRBAVG||Clear-sky and All-sky TOA Fluxes, Surface (Radiative) Fluxes, OLR, Clear-sky and All-sky Albedo, Cloud Properties, Surface Types|
|SSF||Cloud Properties, TOA Fluxes, Surface (Radiative) Fluxes, Unfiltered Radiances, Filtered Radiances, OLR, Surface Types|
|SSF1deg||Cloud Properties, TOA Fluxes, Surface (Radiative) Fluxes|
|SYN1deg||Cloud Properties, TOA Fluxes, Atmosphere Fluxes, Surface (Radiative) Fluxes, Aerosols|
|SYN/AVG/ZAVG||Clear-sky and All-sky TOA Fluxes, Surface (Radiative) Fluxes, OLR, Clear-sky and All-sky Albedo, Cloud Properties, Surface Types, Radiative Flux Profiles|
- Clouds and Computed Flux Profile Data Sets represent surface, within-atmosphere, and Top-of-Atmosphere (TOA) fluxes from radiative transfer model calculations with inputs from several sources.
- Clouds and TOA/SFC Flux Data Set represents TOA and surface radiation derived from CERES and imager measurements.
- ERBE-like Data Sets are consistent with earlier ERBE processing.
- CERES-NEWS-CCCM data sets integrate measurements from CERES, MODIS, CALIPSO, and CloudSat.
- CERES-MISR-MODIS (SSF-SSFM) data sets integrate measurements from CERES, MISR, and MODIS.
- Instrument data (BDS) represent Instrument Data.
- SSF/SYN1deg-lite Data Sets represent Single Scanner Satellite Footprint (SSF), Synoptic Radiative Fluxes (SYN), clouds, TOA and surface fluxes with improved CERES instrument Edition 3 (2010) calibration, processed with Edition 2 algorithms.
|Level 1B||Data products are processed to sensor units. The BDS product contains CERES footprint filtered broadband radiances, geolocation and viewing geometry, Sun geometry, satellite position and velocity, and all raw engineering and status data from the instrument.||BDS|
|Level 2||Data products are derived geophysical variables at the CERES footprint resolution as the Level 1B source data. They include the Level 1B parameters, along with the retrieved or computed geophysical variables such as radiative broadband fluxes and their associated MODIS cloud properties.||CRS, ES-8, SSF|
|Level 3||Data products are the radiative fluxes and cloud properties that are spatially averaged into uniform regional and zonal grids and globally and also temporally averaged into daily, monthly hourly, or monthly means.||AVG, ZAVG, ES-4, ES-9, FSW, ISCCP-D2like, SFC, SRBAVG, SYN, SSF/SYN1deg-lite|
|Level 3B/4||Level 3 data products that are adjusted within their range of uncertainty so as to satisfy known constraints on the climate system (e.g., consistency between average global net TOA flux imbalance and ocean heat storage).||EBAF|
Subsetting allows users to create smaller files (subsets) of the original data by selecting desired parameters, parameter criterion, or latitude and longitude coordinates.
- Energy Balanced and Filled (EBAF) Level 4 data sets with monthly and climatological regional, zonal, global averages of TOA clear-sky and all-sky LW and SW fluxes, where the net flux is constrained to the global heat storage in netCDF format.
- Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) Level 2 data sets that are one hour of instantaneous CERES data for a single scanner instrument in HDF format.
- Single Scanner Satellite Footprint, TOA, Surface Fluxes and Clouds (SSF1deg-lite) Level 3 10 year data sets with a reduced parameter list of monthly and daily data in netCDF format.
- Synoptic Radiative Fluxes and Clouds (SYN1deg-lite) Level 3 10 year data sets with a reduced parameter list of monthly and daily data in netCDF format.
Order CERES Level 3 Edition 2.5 "lite" subset data from the CERES Level 3 Ordering Page.
CERES file names are formed using the dataset name, configuration code and date information which make each file name unique.
A Dataset name consists of CER_<ProductID>_<Sampling-Strategy>_<Production-Strategy>
The SSF Filename consists of the <Dataset name> combined with the <Configuration Code> and <Date> to make it unique
<ProductID> Identification value - CRS, ES8, SSF, SYN
<Sampling-Strategy> Satellite, instrument, and imager - TRMM-PFM-VIRS, Terra-FM1-MODIS, Aqua-FM3-MODIS
<Production-Strategy> Edition or campaign - At-launch, Edition2, ValidationR1
<Config-Code> 6-digit file and software version management code number - 120145
<Date> Date in the form YYYYMMDDHH - 200105812 (May 28, 2001 GMT hr12)
|CRS||Consistent flux and cloud properties.|
|EBAF||Best estimate (net-balanced) TOA fluxes. Evaluation of climate model and energy budget.|
|ERBE-like||Compares original ERBE(1985 - 1989) fluxes with CERES. No CERES algorithm improvements.|
|FLASHFLUX||Quicklook near real-time.|
|ISCCP-D2like||Monthly cloud properties in a similar format to ISCCP.|
Instantaneous footprint radiances, fluxes and MODIS clouds.
TOA fluxes and clouds to compare with A-train (Aqua) products.
TOA fluxes for long term climate trend evaluation, use SSF with associated cloud and aerosol properties.
|SSF/SYN1deg-lite||10 year dataset (2000 - 2010) with an abbreviated parameter list and the latest CERES instrument calibration.|
Best estimate surface fluxes.
Instantaneous footprint level.
- Order online ASDC Web Ordering Tool data available for ftp download.
- Order online CERES Subsetter Ordering Page data available for ftp download.
- Order online Reverb Search Tool data available for ftp download.
- Download the Readme and UNIX C shell script to extract regional CERES non-geo fluxes from the CERES SRBAVG1 HDF file.
Earth Radiation Budget Experiment (ERBE) is a NASA satellite measurement project that came about in the late 1970's as a result of NASA recognizing the importance of improving our understanding of the radiation budget and its effects on the Earth's climate, and a need to make accurate regional and global measurements of the components of the radiation budget. ERBE observations were collected from three satellites that measured global albedo, outgoing and reflected fluxes, and solar incidence. The first full calendar month of ERBE observation began on November 1984. The ERBE project officially ended after the decommission of the NASA ERBS satellite mission on August 2005. All ERBE data are permanently archived at the NASA Langley Atmospheric Science Data Center.
The three satellites ERBS, NOAA-9, NOAA-10 carrying two ERBE instrument packages (Scanner and NonScanner) were used. The NASA Goddard Space Flight Center built the Earth Radiation Budget Satellite (ERBS) on which the first ERBE instruments were launched by the Space Shuttle Challenger in 1984. ERBE instruments were also launched on two operational National Oceanic and Atmospheric Administration (NOAA) weather monitoring satellites, NOAA-9 and NOAA-10 in 1984 and 1986, respectively.
Earth Radiation Budget Satellite (ERBS) is a dedicated NASA research satellite launched by Space Shuttle Challenger in October 1984 and was the first spacecraft to carry ERBE instruments into orbit. ERBS is in a precessing orbit (57 degree) allowing the ERBE instruments on board this satellite to provide complete diurnal sampling in 72 days. The ERBS satellite mission came to an official end on August 2005 after 20+ years of continuous operations.
The Radiation Budget represents the balance between incoming energy from the Sun and outgoing thermal (longwave) and reflected (shortwave) energy from the Earth.
Global spatial coverage is provided by the ERBE instruments on board the NOAA-9 and NOAA-10 satellites. Coverage between 60 degrees north and south latitude is provided by ERBS satellite. ERBS is a precessing satellite and produces the best diurnally sampled data because it sees all 24 hours of local time in 72 days. NOAA-9 and NOAA-10 are sun-syn satellite and do not cover the entire diurnal cycle, however they see the entire globe. NOAA-9 is the afternoon (2:30 PM LST) satellite and NOAA-10 is the morning (7:30 AM LST) satellite.
The ERBE/ERBS instruments operated from November 1984 to August 2005. The ERBE/NOAA 9 instruments operated from February 1985 to November 1992. The ERBE/NOAA 10 instruments operated from January 1986 to November 1992. ERBE data availability depends on both instrument type and satellite.
These are two types of instruments specifically designed by a team of electronic, thermal, and mechanical experts, built and integrated with the ERBS and NOAA satellite platforms by TRW of Redondo Beach, CA.
A set of three co-planar detectors (longwave, shortwave and total energy), all of which scan from one limb of the Earth to the other, across the satellite track (in its normal operational mode).
The scanner instrument has a smaller footprint (40 km at nadir) and scanned across the orbit plane to provide maximum spatial coverage. The scanner measures directional radiance, not hemispheric flux. The directional radiance is converted to hemispheric flux using empirical statistical model (ERBE ADM). The scanner is designed for regional to large scale analysis, and due to the smaller footprint, the scanner product is able to separate clear sky data from all-sky data to provide both clear-sky and all-sky estimates.
A set of five detectors; one which measures the total energy from the Sun, two which measure the shortwave and total energy from the entire Earth disk, and two of which measure the shortwave and total energy from a medium resolution area beneath the satellite.
The Nonscanner instrument did not scan and pointed straight down to measure hemispheric flux from the Earth. The large footprint (1000 km) is designed only for large scale analysis, thus products provide only all-sky data. Because the nonscanner had less moving parts, it lasted a lot longer than the scanner instrument.
- Total Channel: 0.2 to 50 microns
- Shortwave Channel: 0.2 to 5 microns
- Longwave Channel: 5 to 50 microns
- Albedo - The ratio of reflective shortwave flux to the solar incoming flux at top of atmosphere (TOA), where zero (0.0) represents total absorption, and one (1.0) represents total reflectance.
- Net - Net Radiation (Net) is the amount of total radiative flux energy deposited into the Earth system at top of the atmosphere (TOA).
- OLR - Outgoing Longwave Radiation (OLR) is an alias for longwave (LW) radiative flux energy leaving the Earth system at top of the atmosphere (TOA).
- RSR - Reflected Shortwave Radiation (RSR) is an alias for shortwave (SW) radiative flux energy leaving the Earth system at top of the atmosphere (TOA).
- Scene Identification - The twelve possible ERBE scene categories constructed from combinations of geography and cloud cover resulting in distinct Angular Distribution Models.
- Solar Incidence - The time integrated value of solar incoming flux into the Earth system at top of the atmosphere (TOA).
- Total Solar Irradiance - The average power received on a unit area at the mean Earth/Sun distance (Watts/square meter).
ERBE net radiation is defined at top of the atmosphere (TOA) as the following:
Net (TOA) = Solar_down (TOA) - SW_up (TOA) - LW_up (TOA)
where Solar_down (TOA) is the solar incoming flux at TOA, SW_up (TOA) is the reflected shortwave flux at TOA, and LW_up (TOA) is outgoing longwave flux at TOA. The sign convention for ERBE net radiation is that positive/negative sign represents a net radiative energy surplus/deficit of the Earth system, respectively.
Cloud radiative forcing (CRF) is not an ERBE parameter. However, it can be calculated from the ERBE scanner data set using the all-sky and the clear-sky parameters as the following:
Cloud Radiative Forcing = Clear-sky Flux - All-sky Flux
Cloud radiative forcing can not be calculated from the ERBE nonscanner data set due to the lack of clear-sky parameters.
ERBE data are available in many different resolutions; ranging from instantaneous satellite footprint data (40km spatial scale), to monthly mean regional averaged gridded data (2.5-degree, 5-degree, and 10-degree grid), to global-monthly mean data. In addition, daily mean regional averages and monthly-hourly regional averages are also available.
- ERBE uses a regular equal-angle grid system. The ERBE regional gridded data is available in three different resolutions (2.5-degree, 5-degree, and 10-degree) depending on the instrument type.
- For the ERBE 2.5-degree regional data set, the ERBE grid contains 10,368 2.5-degree regions. This maps to 72 latitude zones with 144 regions in each (72 * 144 = 10368). The first ERBE 2.5 degree region is located at the North Pole - Greenwich meridian. The center location of region 1 is at 88.75N and 1.25E. The 2.5 degree grid extends eastward, one 2.5 degree region at a time, around the entire 2.5-degree latitude circle and then step southward, one 2.5-degree latitude zone at a time, until it reaches region 10368, which is centered at 88.75S and 358.75E.
- For the ERBE 5-degree regional data set, the ERBE grid contains 2592 5-degree regions. This maps to 36 latitude zones with 72 regions in each (36 * 72 = 2592). The first ERBE 5-degree region is located at the North Pole - Greenwich meridian. The center location of region 1 is at 87.5N and 2.5E. The 5-degree grid extends eastward, one 5-degree region at a time, around the entire 5-degree latitude circle and then step southward, one 5-degree latitude zone at a time, until it reaches region 2592, which is centered at 87.5S and 357.5E.
- For the ERBE 10-degree regional data set, the ERBE grid contains 648 10-degree regions. This maps to 18 latitude zones with 36 regions in each (18 * 36 = 648). The first ERBE 10-degree region is located at the North Pole - Greenwich meridian. The center location of region 1 is at 85N and 5E. The 10-degree grid extends eastward, one 10-degree region at a time, around the entire 10-degree latitude circle and then step southward, one 10-degree latitude zone at a time, until it reaches region 648, which is centered at 85S and 355E.
The ERBE region number can be easily determined with the following:
2.5-degree Data: Region number = int(colat / 2.5) * 144 + (lon / 2.5)
5-degree Data: Region number = int(colat / 5) * 72 + (lon / 5)
10-degree Data: Region number = int(colat / 10) * 36 + (lon / 10)
where colat = 90 - latitude
For users working with regional data needing global averages, area weighting needs to be applied to the regional averages because of the equal-angle grids. Global data are also available in the S4 data sets.
Compilation successful but values read seem off:
Check to see what bit machine you're running on. If it is a 64-bit machine, check to see if the is a 32-bit compile option available. Other issues affecting compilation would be differing versions of the operating system and compilers the read software are being run on.
Big Endian Little Endian:
Unix machines are Big Endian architecture while Linux systems are Little Endian architecture. Data generated on a Unix machine are byte swapped on the Linux machine when data files are transferred.
Any zip files need to be unzipped before use. Most programs only read one file at a time.
More information is in the Data Access Questions section.
Please submit your science questions directly to the NASA Langley Atmospheric Science Data Center's (ASDC's) User Services. They will forward them to the volunteer scientists assigned to the ERBE data sets. Since the ERBE project has officially ended, the science support is very limited and depends on the availability of our volunteer scientists. It may take a few days to receive your answers.
- Level 1: NonScanner data: TSI
- Level 2: Instantaneous unfiltered satellite footprint data: S-7, S-8
- Level 3: Monthly Averaged gridded data: S-4, S-4N, S-4G, S-4GN, S-9, S-10, S-10N
|S-4||Regional, Zonal, and Global Averages|
|S-4N||NonScanner Regional, Zonal, and Global Averages|
|S-4G||Regional, Zonal, and Global Averages|
|S-4GN||NonScanner Regional, Zonal, and Global Averages|
|S-9||Scanner Earth Radiant Flux and Albedo|
|S-10||NonScanner Earth Radiant Flux and Albedo|
|S-10N||NonScanner Earth Radiant Flux and Albedo|
|S-7||NonScanner Medium-Wide FOV Data Tape|
|S-8||Processed Archive Tape|
|TSI||Total Solar Irradiance|
The data are available in both native format (NAT), and Hierarchical Data Format (HDF) as listed and described in the Earth Radiation Budget Experiment (ERBE) Langley ASDC Project Document. The following provide a quick summary of the available data.
Scanner and Nonscanner
|Total Solor Irradiance|
|Temporal Coverage||11/1984 - 02/1990:||11/1984 - 11/1995:||11/1984 - 09/1999:||10/1984 - 03/2003:|
There are single satellite and combined-satellite scanner products. The best source for these data is to order the ERBE scanner CD which gives all the S4G monthly mean 2.5 degree gridded data from both single satellite and combined-satellite product in ASCII format. Also, ordering the S4G HDF data online and using the ncdump utility to perform a straight ASCII dump is another option. NOAA-9 and NOAA-10 provide global coverage at different local sampling times. These do not provide the full diurnal coverage, which can affect the quality of the shortwave and longwave estimate. ERBS covers all 24-hour local time, but only for regions between 60N and 60S.
Scanner and Nonscanner instruments are processed independently using separated instrument calibration procedure and data processing algorithm. Because of these differences, it is best to work with these two data sets separately.
- ERBE/ERBS scanner operated for ~5 years: November 1984 - February 1990
- ERBE/NOAA-9 scanner operated for ~2 years: February 1985 - January 1987
- ERBE/NOAA-10 scanner operated for ~2 years: January 1987 - April 1989
Even though NOAA-9 and NOAA-10 continued to fly mid to late 1990's, the ERBE Nonscanner record stopped due to instrument failure. Currently only the ERBE/ERBS noncanner data have been reprocessed to correct for satellite altitude drift and other instrument related issues. These new data are only released as the ERBE/ERBS S10N Edition3 product. More information is available in the Edition3 Data Quality Summary, including a special website to obtain user-applied corrected and ASCII formatted data. No S4GN data is available for this latest data. NOAA-9 and NOAA-10 data have not been reprocessed to correct for the satellite altitude drift issue with no plans for a future fix. The satellite altitude drift only affects the Noncanner data set. The scanner data set is not affected by this issue.
Scanner and Nonscanner instruments are processed independently using separated instrument calibration procedure and data processing algorithm. Because of these differences, it is best to work with these two data sets separately.
|ERBE/ERBS||Nonscanner operated for ~20 years||November 1984 - August 2005|
|ERBE/ERBS S10N Ed3||Nonscanner operated for ~14 years||January 1985 - September 1999|
|ERBE/NOAA-9||Nonscanner operated for ~8 years||February 1985 - November 1992|
|ERBE/NOAA-10||Nonscanner operated for ~8 years||February 1985 - November 1992|
** Note** : ERBE/ERBS nonscanner TOA flux data from October 1999 to August 2005 is unavailable to the public due to unresolved instrument anomaly issues.
|NFOV||narrow field-of-view||2.5 degree resolution|
|MFOV-NF||medium field-of-view||numerical filter||5.0 degree resolution|
|WFOV-NF||wide field-of-view||numerical filter||5.0 degree resolution|
|MFOV-SF||medium field-of-view||shape factor||10.0 degree resolution|
|WFOV-SF||wide field-of-view||shape factor||10.0 degree resolution|
Sample Filename: s4gn_wnf5._yymm_s
"yy" represents the year (e.g., 89 - 1989);
"mm" represents the number value of a month (e.g., 01 = January, 12 = December)
"s" represents the satellite code:
1 = NOAA-9
2 = ERBS
3 = NOAA-10
4 = NOAA-9/NOAA-10
5 = ERBS/NOAA-9
6 = ERBS/NOAA-10
7 = NOAA-9/ERBS/NOAA-10
- Telemetry - Process data from NOAA and GSFC to a common format, interpret the instrument and spacecraft housekeeping data, and analyze instrument commands and in-orbit environment.
- Ephemeris - Analyze orbit position data from GSFC for each of the three satellite platforms.
- Merge/Count Conversion - Combine telemetry and ephemeris data to produce Earth location geometry and convert radiometric counts produced by the instruments into satellite-altitude radiances.
- Inversion - Identify the scene viewed by the instruments and interpret the measurements at the top of the Earth's atmosphere using shape factor and numerical filter inversion techniques.
- Daily and Monthly Time/Space Averaging - Convert from time-ordered to regionally-accessible data sets and apply diurnal models to estimate hourly, daily, and monthly averages of radiation budget components.
- Data Products - Generate well-documented science archival products in an easily accessible format.
ISCCP is the International Satellite Cloud Climatology Project, established in 1982 as part of the World Climate Research Programme (WCRP), to collect and analyze satellite radiance measurements to determine the global distribution of clouds, their properties, and their diurnal, synoptic, seasonal and interannual variations.
ISCCP data can be obtained from the ISCCP Data and Information page on the ASDC EOSWEB site, the ISCCP Homepage, NOAA’s (National Oceanic and Atmospheric Administration) website and MY NASA DATA.
The EOSWEB site provides a complete profile of the ISCCP data, parameters, documentation,
readme file, read software to read the data, and order tool access for ordering the data.
EOSWEB site: ISCCP table
The ISCCP homepage provides data, documentation, data descriptions, software, other cloud data, maps, and plots.
The NOAA website provides ISCCP data from the Satellite Data Access page.
NOAA’s website: http://www.ncdc.noaa.gov/data-access/satellite-data/satellite-data-access-datasets
MY NASA DATA's Live Access Server(Advanced Edition); gives you a quick way to get an overview of, obtain data, and easily plot various types of data. The LAS contains over 200 parameters in atmospheric and earth science from five NASA scientific projects.
MY NASA DATA: https://mynasadata.larc.nasa.gov/las/getUI.do
See the MISR web site, and also Diner, D. J. et al. "Performance of the MISR Instrument During Its First 20 Months in Earth Orbit", IEEE. Trans. Geosci. Rem. Sens. 40 (7), 1449-1466 (July 2002).
|Camera View Zenith Angles at Earth's Surface||0.0 ° (nadir), 26.1, 45.6, 60.0 and 70.5 ° (both fore and aft of nadir)||
Local Mode (targeted):
|Swath Width||360 kilometers (224 miles) (9-day global coverage)|
|Cross-Track x Along-Track Pixel Sampling||
275 x 275 meters (902 x 902 feet)
550 x 550 meters (0.34 x 0.34 mile)
1.1 x 1.1 kilometers (0.68 x 0.68 mile)
275 meters x 1.1 kilometers (0.17 x 0.68 mile)
|Spectral Bands (Solar Spectrum Weighted)||446.4, 557.5, 671.7, 866.4 nanometers|
|Spectral Bandwidths||41.9, 28.6, 21.9, 39.7 nanometers|
Measuring the reflectance of a target from different directions is really useful because geophysical media (the atmosphere, including the clouds and aerosols, the ocean, and terrestrial surfaces such as soil, vegetation and snow or ice) reflect solar light differently in different directions. In fact, the variations between the reflectances acquired from a variety of observation angles can be interpreted (with appropriate models) to document the properties of the target, just as the more familiar spectral differences are exploited to document its chemical composition.
Most imaging space-borne instruments acquire measurements for each location on Earth from a single direction at a time, usually within the limited range of (across-track) observation zenith angles allowed by the scanner or push-broom design of the sensor. The accumulation of multiangular observations with such instruments necessitates revisiting the site over rather long periods of time, from multiple days to a few weeks or more. By incorporating nine separate cameras oriented at various angles along the track of the platform, the MISR instrument is capable of acquiring multiple observations of the same site from a wide variety of zenith angles in a matter of a few minutes. This greatly facilitates the interpretation of the measurements and significantly improves the accuracy of the retrieved information.
Specifically, using its multi-angular and multi-spectral capability, the MISR instrument
- better distinguishes between objects and surfaces than would be possible on the basis of spectral variations alone;
- exhibits an enhanced sensitivity to aerosols and thin cirrus clouds, both of which are ubiquitous and usually hard to detect, especially at large observation zenith angles and/or over bright backgrounds;
- provides a three-dimensional (stereoscopic) view of clouds that allows users to estimate their height;
- makes it possible to use clouds as tracers of winds aloft due to the time lapse (about 7 minutes) between the most forward and the most backward views;
- yields at once measurements that accentuate or minimize the effect of sun glint over the ocean and other water surfaces, thereby enabling observations even when traditional sensors are hampered by the very high reflectance of these surfaces, and
- permits users to much more accurately estimate the hemispherical albedo of the target, which is thus calculated on the basis of nine different values instead of only one.
More detailed information is provided on the MISR web site Science Goals and Objectives page.
The instantaneous swath of any imaging instrument, including MISR, is the width of the region that is actually observed across the track of the instrument at any time during any particular overflight. The instantaneous swathes of the cameras on the MISR instrument vary from 376 to 414 km, but the instantaneous swath of the overlap of all cameras is 360 km. This means that whenever MISR passes exactly overhead of a site, its nine cameras also observe the neighborhood of that site, up to 180 km on either side of the projection of the track of the Terra platform on the Earth's surface. The swath also refers to the entire region being observed by MISR in the course of one particular orbit: in this case, it refers to an area that is about 20,000 km long and 360 km wide.
The Terra platform that carries MISR and other scientific instruments flies at an altitude of 705 km above sea level on a sun-synchronous orbit. It revolves once around the planet in 98.88 minutes and thus completes about 14.5 revolutions per day. In the context of MISR data exploitation, each complete revolution is called an orbit, and orbits are consecutively numbered from launch. The number of the orbit is thus directly related to the time span since launch.
In practice, since MISR is an optical sensor that measures the reflectance of the Earth in the solar spectral range, it is acquiring useful data only while the Terra platform is over the illuminated (day) side of the planet, i.e., during one half of the complete orbit or a bit less. Of course, the Earth itself keeps turning around its own axis while Terra proceeds on its orbit. As a result, when Terra completes an orbit and initiates the next one, it actually flies over quite different regions. The orbit number thus also indicates the areas of the planet observed. For these reasons, the orbit number is explicitly included in the name of many MISR data and product files.
The sun-synchronous orbit of Terra was selected in such a way that after 233 revolutions around the planet, or some 16 days, the platform returns to exactly the same locations and observes them under nominally identical angular conditions. Because of the 360 km instantaneous swath width of the MISR instrument, it is possible to gather multiple sets of observations (each with 9 cameras and 4 spectral bands) of a particular site in 2 days (Poles) to 9 days (Equator), depending on its latitude, but of course under a variety of angular conditions.
An Orbit/Date Conversion tool is available from the ASDC web site.
The generic data file for MISR is a swath, i.e., a set of measurements for the entire area observed during the day part of the orbit. This is a very large amount of data. To simplify the storing and processing of these data, swathes are broken into a series of predefined, uniformly-sized boxes along the ground track called blocks. Each path is divided into 180 blocks measuring 563.2 km (cross-track) x 140.8 km (along-track). For a given path, a numbered block always contains the same geographic locations. Hence, areas that are close to each other in latitude will belong to blocks with similar numbers. Because of seasonal variations in the portion of the Earth that is in daylight, only up to about 142 blocks will contain valid data at any particular time.
The MISR instrument continuously acquires data everywhere on Earth, but with a frequency that is dependent on the latitude of the location of interest. Indeed, due to the overlap of the swathes near the poles and their wide separations at the equator, repeat coverage varies from 2 to 9 days, respectively.
The nine MISR cameras acquire measurements every 275 m across track (250 m for the An camera). However, the data rate that would be required to transmit all the measurements from the nine cameras in the four spectral bands at that full resolution would exceed the capacity allocated to the MISR instrument on the Terra platform. To retain some of the high spatial resolution of the sensors without exceeding the data transfer quotas, MISR can be operated in two different data acquisition modes:
- In global (default) mode, a special averaging scheme is conducted on-board such that the data from all cameras other than An and all spectral bands other than red are averaged to 1.1 km before transmission to the receiving station. The spectral data (all 4 bands) from the An camera and the directional data in the red spectral band from all 9 cameras are therefore always available at the full spatial resolution.
- In local mode, it is possible to transmit all the data at the full resolution, but only for limited periods of time and therefore for limited regions, typically about 300 km in length (along track). Please refer to the MISR technical documentation for a detailed description of the various programming modes. Users may contact the ASDC User and Data Services office to request local mode observations.
Bands 1-4 are blue, green, red, and near-infrared, respectively. Variations in spectral response from one camera to another, for the same band, are minor and a standardized, downloadable spectral response curve in text format for each of the bands is available. Summary spectral response information (e.g., bandcenter, bandwidth) is also available in the Ancillary Radiometric Product ARP_INFLTCAL file, and the mathematical definitions of the product contents are provided in MISR Level 1 In-flight Radiometric Calibration and Characterization Algorithm Theoretical Basis Document (ATBD-MISR-02). A moments analysis is used to define the "in-band" spectral region. Because the filters are not perfect, there is a small amount of "out-of-band" light (less than 2% of the integrated energy), and the ARP_INFLTCAL file provides spectral response information for both the in-band region of each filter as well as for the total band.
Zenith angles are positive values measured from the local vertical at each point. Azimuth angles are measured clockwise from the direction of travel to local north. For both the Sun and cameras, azimuth describes the direction in which the photons are traveling. According to this convention the solar azimuth angle is therefore near 270 degrees when Terra is close to the equator, because of its morning equator crossing time. Additionally, the difference in view and solar azimuth angle will be near 0 degrees for forward scattered light, and near 180 degrees for backward scattered light. Sun and View angles are available in the MISR Geometric Parameters (MIB2GEOP) data product. Sun angles are also available in the L1B2 data files.
The Earth Science Data Type (ESDT) Version is used in the Reverb Search Tool (V001, V002, etc). The ESDT Version is incremented when a significant change to the product occurs.
The format Version is used to distinguish between software deliveries to ASDC that result in a product format change. The format version is given in the MISR data file name using the designator _Fnn_ where nn is the version number.
The product version is given in the MISR data file name using the designator _nnnn_ where nnnn is the product version number. Early on in the mission, several significant changes to ancillary datasets were required, and these changes triggered Product Version increments. At this point in time, most of the static ancillary data sets have stabilized and major changes to them are not predicted. Therefore, product version numbers are not necessarily incremented because of ancillary data set deliveries.
As MISR continues to reprocess the data products, Collections of scientifically consistent sets of data product versions become available. Collections may contain multiple format, production, and ESDT Versions.
An example of MISR's file naming convention is: MISR_AM1_GRP_TERRAIN_GM_Pxxx_Oxxxxxx_XX_Fnn_nnnn.hdf, where
MISR = Instrument Name
AM1 = Satellite Name
GRP_Terrain_GM = Georectified Radiance Product Terrain (Land Surface) Global Mode
Pxxx = Path Number
Oxxxxxx = Orbit Number
XX = Camera
Fnn = Format version of the product
nnnn = Product Version number
Individual MISR data set file naming conventions are found in the Project Guide.
Intensive assessment of MISR product data quality is an ongoing activity. Focused studies of some parameters are completed. Quality designators indicate the maturity of products and individual parameters. A product may contain parameters at varying quality levels. Below are the Maturity Level definitions:
|Beta:||Early release products for users to gain familiarity with data formats and parameters.|
|Provisional:||Limited comparisons with independent sources have been made and obvious artifacts fixed.|
|Validated Stage 1:||Uncertainties are estimated from independent measurements at selected locations and times.|
|Validated Stage 2:||Uncertainties are estimated from more widely distributed independent measurements.|
|Validated Stage 3:||Uncertainties are estimated from independent measurements representing global conditions.|
There are three reasons that the ground coverage of two MISR images within the same path and block may differ.
- The position and pointing of the Terra satellite can vary by a small amount from orbit to orbit. For instance, the position is allowed to vary by no more than 20 km from one overpass to the next. If two images from the same camera for different overpasses are compared, a slight horizontal offset in image location can often be seen. This offset is usually the result of a shift in position of the satellite.
- The nine MISR camera footprints do not all cover the same exact extent on the ground. This variance occurs because the different camera views are acquired from devices which have different optical designs. In addition, the Earth rotates underneath the satellite in the time that elapses between acquisitions of a particular ground target by two different MISR cameras. Crosstrack boresight offsets are included in the MISR camera pointing angles to compensate, but this does not result in perfect overlap at every latitude. Therefore, two images from the same orbit but from different cameras almost never display precise overlap. A slight horizontal offset between any two camera images is usually visible.
- The MISR cameras are only commanded to acquire imagery over the sunlit portion of the Earth. Therefore a significant seasonal variation of the start block and stop block occurs for orbits within the same path. For example, some blocks acquired in Antarctica in December will not be acquired in June because they are dark during the later month.
The nadir camera Level 1 images have a swath width of about 376 km, compared to 414 km for the off-nadir cameras. The widths are different because the focal lengths of the MISR cameras change in relationship to the varying distance to the Earth for the different cameras. When viewing the same Earth area with a more oblique-pointing camera the focal length must be greater in order to preserve resolution. All of the camera images are 1504 pixels wide, and the focal lengths of the D, C, B, and off-nadir A cameras are chosen so that each pixel is 275 m wide. However, the nadir A camera uses the same focal length as the off-nadir A cameras, so each of its 1504 pixels is only 250 m wide. Another factor affecting overlap is Earth rotation during the time interval between when each camera acquires its image of a given area. The area of overlap among the cameras depends on latitude. Even though the forward and backward D camera (for example) have the same swath width, it is possible for the common area viewed by both to be less than 414 km.
SOM is a space-based map projection in which the reference meridian nominally follows the spacecraft ground track. It provides a mapping from latitude and longitude to a coordinate system that is approximately aligned with the MISR swath. SOM was used because it minimizes distortion and resampling effects, and permits the greatest flexibility in the choice of Earth-based projections. SOM also allows direct cross-comparison with data from other instruments and simplifies global mapping, since the data have already been geolocated. For more information see the MISR Level 1 Georectification and Registration Algorithm Theoretical Basis Document (ATBD-MISR-03), and also Snyder, J.P., Map Projection - A Working Manual, United States Geological Survey Professional Paper 1395, U.S. Government Printing Office, Washington, DC (1987).
SOM vs Lat/Lon
MISR, the Multi-angle Imaging SpectroRadiometer instrument, was successfully launched into sun-synchronous polar orbit aboard Terra, NASA's first Earth Observing System (EOS) spacecraft, on December 18, 1999. MISR measurements are designed to improve our understanding of the Earth's environment and climate. Viewing the sunlit Earth simultaneously at nine widely-spaced angles, MISR provides radiometrically and geometrically calibrated images in four spectral bands at each of the angles.
MISR provides new types of information for scientists studying Earth's climate, such as the partitioning of energy and carbon between the land surface and the atmosphere, and the regional and global impacts of different types of atmospheric particles and clouds on climate. The change in reflection at different view angles affords the means to distinguish different types of atmospheric particles (aerosols), cloud forms, and land surface covers. Combined with stereoscopic techniques, this enables construction of 3-D models and estimation of the total amount of sunlight reflected by Earth's diverse environments.
MISR acquires systematic multi-angle imagery for global monitoring of top-of-atmosphere and surface albedos and to measure the shortwave radiative properties of aerosols, clouds, and surface scenes in order to characterize their impact on the Earth's climate.
Illustrations of MISR instrument viewing the Earth:
MISR data products are grouped into three processing Levels. Level 1 processing provides corrected (or calibrated) instrument data. These data are processed and calibrated to remove many of the instrument effects. The resulting products thus contain minimal instrument or spacecraft artifacts and are most suitable for subsequent scientific derivations. Level 2 processing provides retrieval of derived scientific quantities, such as atmospheric aerosol and cloud measurements. Level 3 processing produces global grids of various parameter elements from the Level 2 products. These global grids are produced daily, monthly, quarterly, and yearly. More detailed descriptions about each of these processing levels can be found in the MISR Project Guide. The MISR data products by processing level are available.
Level 3 globally gridded products became available in July 2002. Level 2 cloud, aerosol, and land surface products became available in February 2001. Level 1 products are available from February 24, 2000 to present. These include Level 1 raw instrument data (Level 1A); radiometrically calibrated radiances (Level 1B1); geolocated, co-registered, map-projected radiances (Level 1B2); browse data; and geometric parameters on a swath-by-swath basis. Additionally, engineering, navigation, and on-board calibrator files are also available, though these are not generally required in order to make use of Level 1 image data. Static data sets also available include the Ancillary Radiometric Product (latitudes and longitudes and surface elevations) and the Ancillary Geographic Product. All currently available data products are listed on MISR Data and Information.
|The MISR Browse Tool allows quick viewing of images from the MISR instrument. The color images are produced from the L1B2 Ellipsoid product for each camera reduced to 2.2km resolution. The MISR red, green and blue bands are used to create the color image, which are intentionally clipped and gamma-stretched to make cloud, ocean and land features visible. The browse images are JPEG format.||Browse Tool Instructions|
MISR data are processed and archived at the NASA Langley Research Center Atmospheric Science Data Center (ASDC). A MISR Order and Customization Tool is available that enables users to order and customize data in a single interface. Some features are non-consecutive path and orbit search; and sorting search results by date, camera, path, orbit, and file version. Customization options are subsetting by parameter, block, and spatial coordinates; additional latitude and longitude layers, and unpacking and unscaling applicable fields; and output data in HDF-EOS stacked-block grid or conventional grid. The reformatting option, referred to as "Conventional HDF-EOS", is designed to be an easier-to-use alternative to MISR's stacked-block format. The interface currently supports two output formats:
- Stacked-block HDF-EOS (original file format)
- Conventional HDF-EOS grid
See FAQ on Customizing and Subsetting MISR products for more information.
MISR data are also available through the ASDC Data Pool (an on-line, short-term data cache that provides a Web interface and FTP access). Specially subsetted and/or reformatted MISR data products supporting field campaigns are also available. Passive FTP mode is required to access the Data Pool from the command line as "ftp -p l4ftl01.larc.nasa.gov", where the system translates to "lower case L four ft lower case L zero one .larc.nasa.gov". A UNIX C shell script method may be used to assist in downloading files from the Data Pool (Readme | Sample script). Data files are stored in directories based on data product and acquisition date. Corresponding metadata files are available in Extensible Markup Language (XML) format.
Depending on the MISR data product, the files can be quite large (for example, a Level 2 Aerosol data product file is approximately 35 Megabytes and a Level 1B2 Radiance file is approximately 600 Megabytes).
MISR observes the entire day-lit side of each orbit. The MISR Production Report allows you to determine what data are available for an orbit range, a date range, or a path range. To obtain an inventory of MISR archive holdings for a specific location or time, submit a query through the MISR Order and Customization Tool which contains the required spatial and temporal constraints. When the query is complete, a list of MISR data files which satisfy the constraints will be displayed in the query results form.
Data for particular geographic locations can be searched via the MISR Order and Customization Tool by selecting products, region of interest, and date. The MISR Browse Tool provides information to help determine paths, orbits and block numbers for specific geographic regions. There is also an Orbit/Date Tool and a Lat/Lon to MISR Path/Block Tool available to determine MISR paths, orbits and blocks. The MISR Production Report, allows you to determine what data are currently available for an orbit range, a date range, or a path range.
The MISR Browse Tool allows quick viewing of images from the MISR instrument. The color images are produced from the L1B2 Ellipsoid product for each camera reduced to 2.2km resolution. The MISR red, green and blue bands are used to create the color image, which are intentionally clipped and gamma-stretched to make cloud, ocean and land features visible. The browse images are JPEG format. After viewing the browse images for your region, note the orbit numbers of interest. The MISR Production Report lists the most currently available data for the selected orbits. Include those orbit numbers when submitting the search for data through the MISR Order and Customization Tool.
Customization allows users to specify the contents and the output format of their MISR products. Currently available features include:
- Spatial subsetting
- Parameter subsetting
- Additional latitude and longitude fields
- unpack and unscale data values
- HDF-EOS conventional grid output format
Subsetting / reformatting is available for MISR Level 1 and Level 2 Standard Data Products. The product maturity designations and quality statements of the original products are applicable to the subsetted / reformatted products. However, some of the transformations executed by the MISR Order and Customization Tool may affect data content. The following products may be customized:
- MIANCAGP - MISR Ancillary Geographic Product
- MIB2GEOP - MISR Level-1B2 Geometric Parameters
- MIRCCM - MISR Level-1B2 Radiometric Camera-by-camera Cloud Mask
- MI1B2E - MISR Level-1B2 Global Mode Ellipsoid-projected Radiance
- MI1B2T - MISR Level-1B2 Global Mode Terrain-projected Radiance
- MB2LME - MISR Level-1B2 Local Mode Ellipsoid-projected Radiance
- MB2LMT - MISR Level-1B2 Local Mode Terrain-projected Radiance
- MIL2TCCL - MISR Level-2 TOA/Cloud Classifiers Parameters
- MIL2TCAL - MISR Level-2 TOA/Cloud Albedo Parameters
- MIL2TCST - MISR Level-2 TOA/Cloud Stereo Parameters
- MIL2ASAE - MISR Level-2 Aerosol Parameters
- MIL2ASLS - MISR Level-2 Land Surface Parameters
One MISR data file is the full swath of data (from terminator to terminator), and the MISR swath-based products are very large. Many users will be interested only in those parts of the swath that cover their region of interest. The MISR Order and Customization Tool enables users to order and customize data in a single interface. Customization options are subsetting by parameter, block, and spatial coordinates; additional latitude and longitude layers, and unpacking and unscaling applicable fields; and outputting data in HDF-EOS stacked-block grid or conventional grid.
Stacked-block HDF-EOS format is a MISR specific extension to the HDF-EOS library that is only used by MISR and is not widely supported by third party data analysis tools. Tools which support HDF-EOS or HDF can usually import stacked-block data to a limited extent. Two problems commonly encountered are: 1) piecing together the MISR blocks so they are aligned correctly with respect to each other; and 2) geolocating the MISR data in a map context. Many tools do not support geolocation of the stacked-block HDF-EOS format. A detailed discussion of the stacked-block HDF-EOS format including instructions on how to write software to geolocate MISR data are discussed in Appendix A of the Data Product Specifications Document.
vs Aligned File
The conventional HDF-EOS format is an alternative format that uses only common HDF-EOS elements, specifically excluding use of the stacked-block extensions. As a result, the conventional HDF-EOS format should be easily imported into any tools that support generic HDF-EOS. In practice however, there are still many tools which have only limited support for HDF-EOS. Conversion to conventional HDF-EOS format attempts to reproduce the data content of the original products, only changing the data format. However, there are some notable differences in the data content for some fields which are discussed below. Geolocation is based on the standard parameters used by the General Cartographic Transformation Package (GCTP) library which is distributed with the HDF-EOS library. Data are map projected using the same Space Oblique Mercator (SOM) projection as the original products.
vs Aligned File
The choice of format largely depends on the tools you are using. Some MISR specific tools, such as misr_view, only support stacked-block format. Tools with only generic support for HDF or HDF-EOS, will be able to display stacked-block data a block-at-time, but will not automatically stitch blocks together with the proper alignment, and will not provide geolocation information.
- If you are using MISR-specific tools such as misr_view or the MISR ENVI Tools, you should use the stacked-block format.
- If you are using generic HDF or HDF-EOS tools, you should use the conventional format.
Most tools that generically support HDF or HDF-EOS should be able to import conventional format. However, tools that only support generic HDF format will not automatically import the HDF-EOS geolocation information.
ENVI version 4.0 (a product of ITT Visual Information Solutions), can successfully import and display most data fields in a conventional HDF-EOS format file. ENVI does not automatically import HDF-EOS geolocation parameters, but this information can be entered manually, using provided ENVI instructions. ENVI does not support import of HDF fields with more than three dimensions, including the X, Y, spatial dimensions. Therefore, MISR parameters including both camera and band dimensions cannot be displayed in ENVI.
In the conversion from stacked-block to conventional format, data is reprojected onto a flat 2-dimensional grid, so that the MISR blocks can be aligned appropriately with respect to each other. For most fields this reprojection is trivial, requiring no resampling; i.e. the reprojected data is identical in content to the original stacked-block format.
The exception occurs for data at resolutions of 35.2 km and 70.4 km. The root of this problem lay within the stacked-block format, which allows the MISR block locations to be offset with respect to each other by multiples of 17.6 km. At pixel resolutions larger than 17.6 km, the block offset is a fraction of a pixel. Therefore, the MISR data is actually computed over an irregular grid in which the pixels are not lined up in regular columns, but instead are shifted by fractions of their size as shown in the illustration of geolocation error (PDF).
This problem affects the following parameters:
|Level 2 TOA/Cloud Albedo (MIL2TCAL)||AlbedoParameters_35.2_km||35.2 km|
|Level 2 TOA/Cloud Stereo (MIL2TCST)||DomainParams||70.4 km|
|Level 2 TOA/Cloud Classifiers (MIL2TCCL)||CloudClassifiers_35.2_km||35.2 km|
|Level 2 Land Surface (MIL2ASLS)||DomParamsAer||70.4 km|
Data for all parameters listed above are shifted by up to one-half a pixel, to align with the nearest pixel in the conventional HDF-EOS grid. All the data numbers, however, remain the same as those in the original products. The effect is a geolocation error of up to 17.6 km for 35.2 km resolution parameters; and up to 35.2 km for 70.4 km resolution parameters. To account for this error, "Latitude" and "Longitude" fields are provided which give the original location of each pixel prior to shifting.
This means there will be two sources of geolocation information for the above parameters. First is the implicit geolocation of each pixel as defined by the GCTP map projection information. This implicit geolocation information will have an error of up to one-half a pixel. Second is the "Latitude" and "Longitude" fields which explicitly specify the lat/lon location for the center of each pixel. The "Latitude" and "Longitude" fields will always have the correct geolocation information. By comparing the implicit lat/lon against the explicit lat/lon, one can determine which pixels have been shifted, and by how much.
See MISR Data and Information for a complete list of data products and the Data Product Specifications for detailed descriptions of the parameters within those products. The main products are the ellipsoid (MI1B2E) and terrain (MI1B2T) projected radiances for each of the cameras, the browse images (MISBR), geometric (MIB2GEOP) parameters (sun and view angles), and the cloud and sun glint mask (MIRCCM).
Level 1A data (the Reformatted Annotated Product, file names containing "FM_SCI") contain raw digital counts from the MISR camera charge-coupled device (CCD) focal planes. At Level 1B1 (the Radiometric Product, file names containing "RP"), the values correspond to calibrated radiances. At Level 1B2 (the Georectified Radiance Product, file names containing "GRP_ELLIPSOID" or "GRP_TERRAIN") the radiance data are geolocated, and geometric co-registration of the data from the different bands and camera angles is performed by resampling to a Space Oblique Mercator (SOM) grid. L1A and L1B1 use the HDF-EOS "swath" interface, and L1B2 uses the HDF-EOS "grid" interface. Most users do not need the L1A and L1B1 data.
The MISR instrument can acquire measurement in Global Mode (GM), Local Mode (LM), and Calibration. Global Mode is the normal acquisition with pole to pole coverage on the day-lit side or the orbit, full resolution (275m) in all 4 nadir bands and the red band of all other angles and 1.1km sampling in all other off nadir bands.
MISR can be configured to disable the on-board data averaging and provide high resolution images in all 36 channels for selected targets and observation times. This capability is referred to as Local Mode (LM). The result is a scene with a crosstrack pixel spacing of 275 meters, with downtrack sampling also at 275 meters, over a spatial area of approximately 300 kilometers downtrack by 360 kilometers crosstrack. LM acquisition can be requested by providing latitude and longitude coordinates, dates, and explanation of data need to User and Data Services.
Most of the time that MISR is acquiring Earth imagery it operates in a configuration called Global Mode, which allows the spatial resolution to be set for each individual channel (there are 36 channels on MISR: 4 bands at each of 9 angles). Currently Global Mode is defined to provide 275-m resolution data in all bands of the An (nadir) camera and in the red band of all the off-nadir cameras (this is the highest resolution available and is called 1x1 data since it involves no on-board pixel averaging). In the remaining channels 4 samples x 4 lines are averaged within the instrument to create a 4x4, or 1.1-km resolution sample. In the L1B2 product, 1x1 data map to a 2048x512 array, whereas 4x4 data map to a 512x128 array. Thus, samples 1-4 in lines 1-4, for example, in 2048x512 data correspond on the SOM grid to the same location as sample 1, line 1, in a 512x128 array.
In order to resample the data from the nine MISR cameras to the SOM grid, it is necessary to assign an altitude to each location on the grid. In the Ellipsoid product, this altitude is represented by the WGS84 ellipsoid. In the Terrain product, it is the altitude of Earth's terrain. Both products are broken arranged into 180 blocks measuring 563.2 km (cross-track) x 140.8 km (along-track). The Terrain product does not contain valid data for blocks that are considered to be completely over water.
|Illustration of Ellipsoid vs Terrain Projection|
Any MISR target which is not at the altitude at which the L1B2 product is registered will show a residual misregistration, or parallax, from one angle to another. This parallax is a function of the target's height relative to the projection altitude. For example, to visualize both topographic relief and cloud altitudes stereoscopically, the Ellipsoid is the appropriate product. Applications which require the data to be co-registered at the land surface altitude should use the Terrain product.
For blocks which contain no land, the 14 most significant bits (MSB) of the Terrain product are assigned the fill value 16379, and the actual image data must be obtained from the Ellipsoid product.
MISR Level 1B2 data products use various high data values to signify fill, and one of the fill values (16377) in the 14 MSB's of the scaled radiances signifies that this location on the SOM grid was obscured from the camera's view by intervening topography. Because greater amounts of topographic obscuration occur at the more oblique angles, the prevalence of this particular fill value increases as the view angle increases. This particular fill value does not apply to the Ellipsoid product, because for each sample, whatever radiance was observed along the line of sight is projected to the ellipsoid grid location.
The Aerosol data (MIL2ASAE) contains aerosol optical depth, aerosol compositional model, ancillary meteorological data, and related parameters on a 17.6 km grid. The Land Surface data (MIL2ASLS) includes bihemispherical and directional-hemispherical reflectance (albedo), hemispherical directional and bidirectional reflectance factor (BRF), BRF model parameters, leaf-area index (LAI) and fraction of photosynthetically active radiation (FPAR), and normalized difference vegetation index on a 1.1 km grid. MISR Top of Atmospheric/Cloud Stereo (MIL2TCST) data parameters include a stereoscopically-derived cloud mask and cloud height on a 1.1 km grid, and reflecting level reference altitude on a 2.2 km grid. Cloud motion parameters are calculated on a 70.4 km grid. The TOA/Cloud Albedo (MIL2TCAL) data contain local albedo values, and the TOA/Cloud Classifiers (MIL2TCCL) contain altitude-binned cloud classifications and angular cloud fractions. Further information is available at MISR Data and Information.
To obtain the complete information about the aerosol models, you will need to order the MISR Aerosol Climatology Product (MIANACP) which contains the Aerosol Physical and Optical Properties (APOP) and the Mixture files. The Mixture file lists the pure particles in each model identifier. The APOP then gives the detailed information for the pure particles. More information on the MISR aerosol model is available from the MISR publications page and the Algorithm Theoretical Basis Document (ATBD).
The Level 3 Component Global Georectified Radiation Product (CGGRP), Component Global Land Surface Product (CGLS), Component Global Aerosol Product (CGAS), and Component Global Albedo Product (CGAL) are generated for daily, monthly, quarterly, and yearly time periods. These data are globally gridded on several grids including 0.5°x0.5°, 1°x1°, or 10°x10°. Selected parameters from these products are available for viewing from MISR Level 3 Imagery. Further information is available at MISR Data and Information.
The Level 3 products are globally gridded statistical summaries of a range of parameters from select Level 1 and Level 2 products. The Levels 1 and 2 products are in swaths, each derived from a single MISR orbit, where the imagery is 360 km wide and approximately 20,000 km long. At Level 3 the product parameters from multiple swaths are combined to make complete, global maps. The Level 3 products are averages of select Level 2 parameters on daily, monthly, quarterly and annual time scales. The MISR Level 3 Imagery provides easy access to images of select parameters within these products.
The "Clim-Likely" aerosol climatology data set was developed as an initial step in identifying a range of components and mixtures for the MISR Standard Aerosol Retrieval Algorithm climatology, and as one standard against which to compare MISR aerosol air mass type retrieval results. Six component aerosols included in the model were medium and coarse mode mineral dust, sulfate, sea salt, black carbon, and carbonaceous aerosols. Five aerosol air mass "Mixing Groups" and thirteen sub-groups were identified from a cluster analysis of the entire set of data. Each Mixing Group contains the four most abundant component particles in the column for climatologically common aerosol air masses. Each sub-group identifies the dominant particles within the Mixing Group. The data are derived from 'typical-year' aerosol transport model results and are available for individual 1° x 1° grid boxes or as global monthly files. The "Clim-Likely" aerosol climatology data set is available from the ASDC. "Clim-Likely" documentation and examples are available from this reference: Kahn, Ralph, Pranab Banerjee, and Duncan McDonald (2001). The sensitivity of multi-angle imaging to natural mixtures of aerosols over ocean. J. Geophysical Res., 106 (D16), 18219-18238 (PDF).
MISR data and imagery are available for many field campaigns. Select data products are subset for the region and dates of interest. Special gridded regional products may be available as well as Local Mode data for select targets within the field campaign region. Specific details on MISR-supported field campaigns are available.
At Level 1A, the 14 most significant bits (MSB) directly represent the raw digital count from the camera's Charge-Coupled Device (CCD). The 2 least significant bits (LSB) of the 16-bit data values are data quality indicators (DQI). A DQI of 0 means the data meet all specifications; 1 means some degradation in quality has occurred but the data are still valid; 2 means the data should not be used for scientific analysis; and 3 means the data are not usable. At Level 1B1, the image data and the data quality indicators are stored as separate fields. The image data values represent "scaled radiances", which means that they must be multiplied by a scale factor to obtain radiance in units of Watts/square meters/steradian/micrometer. These band-by-band scale factors are stored in the swath metadata of L1B1 files, and are found within the attributes of the swath structures. The data quality indicators follow the same convention described above.
For Level 1B2 data, the image data and the data quality indicators are once again packed into 16-bit words. The 14 MSB's represent "scaled radiances", and the 2 LSB's are DQI values that follow the same convention described above. The conversion from scaled radiance to radiance (Watts/square meters/steradian/micrometer) requires multiplication by a scale factor. These band-by-band scale factors are stored in the grid metadata of L1B2 files, and are found within the attributes of the grid structures. Note that certain high values of the scaled radiances at L1B1 and L1B2 are reserved for fill, as described in the Data Product Specification Document.
Since November 2002 (product version 0016 and later), the MISR L1B2 products contain parameters within the file that make it easier to convert to BRF. The BRF conversion factor for each band is derived from the equation:
(pi * SunDistanceAU2) / (std_solar_wgted_height * cos(SolarZenith))
This factor can be used to calculate the BRF:
BRF = BRF conversion factor * Radiance
The Radiance may be obtained from the Radiance/RDQI by right-shifting 2 bits, then multiplying the result by the Scale factor (radiometric) contained in the Radiance Grid Metadata.
The value is stored in the MISR Ancillary Geographic Product (AGP), of which there are 233 unique files, one for each of the World Reference System-2 (WRS-2) paths. Like the L1B2 products, these are divided into blocks, and the fields within the "Standard" grid of the AGP are provided at 1.1-km sampling. The average elevation over a 1.1-km grid sample are provided in the "AveSceneElev" field. AGP files can be obtained from the MISR Order and Customization Tool and through the ASDC Data Pool.
This process is described in the MISR Data Product Specifications, Appendix A. There are two methods for doing this:
Look up the Lat/Lon of the corresponding block, line, sample in the Ancillary Geographic Product (AGP) data sets.
MISR geolocation information is located in the MISR Ancillary Geographic Product (AGP) files. The fields "GeoLatitude" and "GeoLongitude" contain the desired information. These values are stored on the "Standard" (1.1 km) grid of the AGP; you may need to interpolate or extrapolate if the parameter you are working with is on a different grid. Latitudes are geodetic, and longitudes are relative to the Greenwich meridian, positive to the east and negative to the west.
You will need to obtain the AGP file that corresponds to the path of the data you are trying to geolocate. The path is given in the MISR data file name using the format _Pxxx_ where xxx is the path number (1-233).
Mathematically convert the SOM block, line, and sample (pixel) to latitude and longitude. This is a two-step process. Algorithms are provided in the DPS Appendix A.
Convert(block, line, sample) <=> SOM(x,y)
Requires several metadata values from the data file and some arithmetic
Convert SOM(x,y) <=> Lat/Lon
Requires use of GCTP (General Coordinate Transformation Package) map projection coordinate conversion library in HDF-EOS distribution or some other software that incorporates GCTP, such as IDL.
- Convert(block, line, sample) <=> SOM(x,y)
The Geometric Parameters files (file names containing "GP_GMP") contain, within each SOM block, solar zenith angle, solar azimuth angle, and view zenith angle and view azimuth angle for each of the 9 cameras. The geometry is established by the MISR camera views, the Sun, and the Terra orbit. To conserve data volume, these parameters are provided on a 17.6-km grid, so you will find the data blocks to be dimensioned 32x8. To get values at 1.1 km or 275 m, you can either interpolate these arrays, or, since the geometric parameters vary slowly spatially, the nearest neighbor should provide sufficient accuracy for most applications. Solar zenith and azimuth are also included in L1B2 file version 16 and later.
Version 6 data is different than earlier versions in five significant ways:
- A small systematic error in the MOPITT geolocation values (latitude and longitude) was identified after the release of the V5 product. This geolocation error has been eliminated in the V6 Level 1, 2, and 3 products.
- For V6, processing, meteorological profiles are derived from the NASA MERRA ('Modern-Era Retrospective Analysis For Research And Applications') reanalysis product (http://gmao.gsfc.nasa.gov/merra/). In previous operational processors, meteorological data were derived from NCEP GDAS (Global Data Assimilation System) analysis products.
- For V6 the CO a priori is based on a climatology for 2000-2009 simulated with the CAM-Chem model. In earlier products, the a priori was based on a climatology for 1997-2004 and was simulated with the MOZART chemical transport model.
- Beginning with the MOPITT V6 products, the format of the archival Level 1, Level 2 and Level 3 data files is switching from HDF-EOS2, based on HDF4 libraries, to HDF-EOS5, based on HDF5 libraries. This represents a major format change and will require that MOPITT product users make major revisions to the tools which they may currently use for opening and reading the content of MOPITT Level 1, 2, or 3 products.
- Two minor changes have been made to the contents of the Level 2 product files. First, the a priori total column value has been added; this quantity simply represents the vertically integrated a priori CO profile. Second, the diagnostic 'Water Vapor Climatology Content' has been deleted. This diagnostic was included in previous products because of a data quality issue with the NCEP water vapor profiles. MERRA-based water vapor profiles are not affected by this issue, and so water vapor climatology plays no role in V6 Level 2 processing.
Note: More details can be found in the: MOPITT (Measurements of Pollution in the Troposphere) Version 6 Product User's Guide: https://www2.acom.ucar.edu/sites/default/files/mopitt/v6_users_guide_201309.pdf
MOPITT has several options for visualizing the data: https://www2.acom.ucar.edu/mopitt/visualization
1. Quick look Images: Daily and Monthly Plots
2. Interactive Data Viewers
3. Diagnostics Timeseries
4. Google Earth KMZ Files
ASDC Data Pool: https://eosweb.larc.nasa.gov/datapool
The Data Pool is an on-line data cache that provides FTP access to select ASDC data products. Data files are stored in directories based on data product and acquisition date.
Examples of using a script to obtain data: https://eosweb.larc.nasa.gov/HPDOCS/datapool/datapool.ftp.readme.txt
Reverb: http://reverb.echo.nasa.gov/reverb 2000 granule (file) limit per order.
MOPITT Subsetter: https://subset.larc.nasa.gov/mopitt/login.php
- This subsetting tool currently operates on MOPITT Version 5 Level 2 products.
- 1000 granule (file) limit per order.
- With the subset tool, you will receive only the data points that fall within your specified lat, long bounds. Without subsetting, even if only one point falls within those bounds, you will receive the entire data granule (file).
The NASA/GEWEX Surface Radiation Budget (SRB) project produces and archives global 3-hourly, daily, monthly/3-hourly, and monthly averages of surface and top-of-atmospheric (TOA) longwave and shortwave radiative parameters on a 1°x1° grid. Starting no later than July 1983 and extending to December 2007.
Here are the basic steps to obtain SRB data:
1. Go to the SRB section of the ASDC's website: SRB page
2. Near the bottom of the page, you will see tabs marked:
3. Hourly Averages, Daily Averages, Monthly Averages, 3 Hourly Monthly Averages, Documentation
Select your preferences of Averages: 3-hourly, Daily, Monthly, or 3-hourly averages:
4. Next, select the NetCDF or Binary link for the Shortwave or Longwave product. It will take you to a page with 3 datasets listed - please select the one
you prefer. This will take you to a page where you can click on the Order Data button for Reverb (ordering tool) or you can use the ASDC HTML Order Tool:
HTML Order Tool
5. You will receive email with status updates and download instructions when the data is ready.
When you receive the notification that the files are ready to be downloaded. The standard time
allowed is 7 days (HTML) or 2 days (Reverb). If you need more time to download the files please contact User Services for assistance.
You can download a program named Panoply Data Viewer from NASA
and it will plot the SRB NetCDF files. It is very easy to use and offers options
to output (Save Image As) the plots in various formats, such as ascii, .jpeg, .gif, .pdf, .tiff and others). You can also manipulate the display in various ways.
This program is free to download and use.
There is also a software called ArcGIS that can be used to visualize NetCDF products. This software requires a license to use.
The read software and readme files (instructions for reading the data) are available on the SRB data set page. Select the “Read Software” tab for access to these files.
At this time, it is not necessary to register in order to obtain SSE Data.
The SSE data provider requests that the following acknowledgement be used when SSE data products are used in a publication:
"These data were obtained from the NASA Langley Research Center Atmospheric Science Data Center POWER Project".
The data obtained from NASA's SSE, POWER, and MY NASA DATA websites are public domain and free of charge. You may use them in your research, publications, and commercial applications.
- On the ASDC web site home page, select "SSE".
- Select “Single Location.”
- Select “Order Data.”
- Enter the Latitude and Latitude of you location in DECIMAL Values and select “Submit”.
- Choose the parameters of interest and select "Submit".
- The resulting page contains monthly averages for each of the selected parameters.
- On the ASDC web site home page , select "SSE".
- Select "Global Data".
- Select "Order Data".
- Select the desired parameter.
- Selecting the parameter name will bring up the data as text in a window, which you can copy and paste into a document.
- Selecting (compressed) to the right of the parameter name will allow you to save a compressed data file on your local machine.
- The resulting page/file contains the monthly and annually averaged values for the selected parameter.
- On the ASDC web site home page, select "SSE".
- Select "Regional Location".
- Select "Order Data".
- Enter both Latitude and Longitude, in DECIMAL Format, of two diagonal corners of a region.
- Select from either box 1 OR box 2:
- Box 1: choose a month and a parameter of interest, and select "Submit".
- Box 2: select a parameter, and select "Submit".
- The resulting page contains data for the monthly average for the selected parameter.
- On the ASDC web site home page, select "SSE".
- Select "Daily Data".
- Select "Order Data".
- Enter Latitude and Longitude
- Select Start Date and End Date.
- Select parameter(s) from the "Download multiple parameters in a column formatted text file" list
- Select one parameter of those just chosen from the "Plot one parameter" list.
- Select "Submit".
- The resulting page displays a plot of the selected parameter with an option to view the parameters chosen for downloading in a text file.
- On the ASDC web site home page, select "SSE".
- Select "Interannual Variability".
- Select "Order Data".
- Enter Latitude and Longitude.
- Select Start Year and End Year.
- Select a parameter.
- Select "Submit".
- The resulting page contains a table of values for the monthly averages of the selected parameter.
- On the ASDC web site home page, select "SSE".
- Select "HOMER".
- Select "Order Data".
- Enter Latitude and Longitude in DECIMAL Format and "Submit".
- Select Submit to preview a new option.
- The following options will be deployed in a future version of HOMER.
- They can be previewed on the SSE web site.
- Start Date: SEE AVAILABLE DATES
- End Date: BESIDE EACH PARAMETER
- The resulting page contains data and graph of the daily values. There is also the ability to get the data as plain text.
TES began making measurements on August 22, 2004. The routine TES observation mode is to produce global survey standard products spanning 16 orbits on a 50% duty cycle, or approximately every other day. The "off" days can be used for special observations such as intensive campaigns to observe volcanic eruptions, biomass burning, and pollution events.
- TES Level 1B data files contain radiometric calibrated spectral radiances and their corresponding noise equivalent spectral radiances (NESR). The geolocation, quality and some engineering data are also provided.
- A Level 1B data file contains data from a single TES orbit for one focal plane. Note that a TES orbit starts at the South Pole Apex.
- A Level 1B granule contains four files for a single orbit, one file for each of the four focal planes. Note that a granule is the orderable quantity of data.
The table below illustrates the TES Level 1B file naming conventions.
ESDT Short Name File Name Product TL1BN TES-Aura_L1B-Nadir_FPfp_rrun id-oorbit number_version id.h5 Standard TL1BSOL TES-Aura_L1B-SO-Low_FPfp_rrun id-oorbit number_version id.h5 Special Observation/Low Resolution TL1BSOH TES-Aura_L1B-SO-High_FPfp_rrun id-oorbit number_version id.h5 Special Observation/High Resolution
- fp represents the two-character focal plane identifier: 1A, 1B, 2A or 2B
- run id represents the ten-digit run identification number.
- orbit number represents the starting five-digit Absolute Orbit number, which is the same as the Aura orbit number at the time of the South Pole apex crossing.
version id represents the version identification number, which is used to keep track of file format and file content changes.
For more information about file version identification, see the TES Data Products Specification document.
- .h5 extension denotes the use of HDF5 file format.
- TES Level 2 files contain measurements of a single molecular species or temperature. The Level 2 Ancillary Data Product contains information such as geolocation and spacecraft position, which are common to the individual Level 2 species and temperature Standard Product files. A TES Level 2 granule contains a single data file.
The tables below illustrates the TES Level 2 file naming conventions.
Standard Products ESDT Short Name File Name TL2CH4N TES-Aura_L2-CH4-Nadir_rrun id_version id.he5 TL2CON TES-Aura_L2-CO-Nadir_rrun id_version id.he5 TL2H2ON TES-Aura_L2-H2O-Nadir_rrun id_version id.he5 TL2O3N TES-Aura_L2-O3-Nadir_rrun id_version id.he5 TL2ATMTN TES-Aura_L2-ATM-TEMP-Nadir_rrun id_version id.he5 TL2ANC TES-Aura_L2-ANCILLARY_rrun id_version id.he5 Special Observations ESDT Short Name File Name TL2CH4NS TES-Aura_L2-CH4-SO-Nadir_rrun id_version id.he5 TL2CONS TES-Aura_L2-CO-SO-Nadir_rrun id_version id.he5 TL2H2ONS TES-Aura_L2-H2O-SO-Nadir_rrun id_version id.he5 TL2O3NS TES-Aura_L2-O3-SO-Nadir_rrun id_version id.he5 TL2TNS TES-Aura_L2-ATM-TEMP-SO-Nadir_rrun id_version id.he5 TL2ANCS TES-Aura_L2-ANCILLARY-SO_rrun id_version id.he5
- run id represents the ten-digit run identification number.
version id represents the version identification number, which is used to keep track of file format changes.
For more information about file version identification, see the TES Data Products Specification document.
- .he5 extension denotes the use of HDF-EOS5 file format.
- The objective of TES SDP L3 subsystem is to interpolate the L2 atmospheric profiles collected in a Global Survey onto a global grid uniform in latitude and longitude that will provide a 3-D representation of the distribution of atmospheric gasses. The L3 standard data products are composed of L3 HDF-EOS grid data.
The L3 standard product files are implemented using the HDF-EOS 5 file format. HDF-EOS 5 files have a default extension of ".he5". The ECS Local Granule ID (filename) for a L3 standard product is constructed using the following template:
File Type File Name Convention daily TES-Aura_L3-<species>_<run id>_<version id>.he5 8-day TES-Aura_L3-<species>-8D<year><doy>_<version id>.he5 monthly TES-Aura_L3-<species>-M<year><month>_<version id>.he5 Notation Format Description <doy> dddd <doy>: first day of the 8-day period
d : day of year format placeholder
ddd : 3-digit number representing day of year
<month> mmm m : month format placeholder
mm : 2-digit number representing month
<run id> rnnnnnnnnnn r : Run ID format placeholder
nnnnnnnnnn : string representing 10-digit Run ID
<version id> Fff_cc F : File format placeholder
ff : 2-digit version number reflecting file format changes
cc : 2-digit version number reflecting content changes
<year> yyyy yyyy: 4-digit number representing year