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ERBE Frequently Asked Questions |
Scanner
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 it's 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.
NonScanner
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.
Cloud Radiative Forcing = Clear-sky Flux - All-sky Flux
Cloud radiative forcing can not be calculated from the ERBE nonscanner dataset due to the lack of clear-sky parameters.For the ERBE 2.5-degree regional dataset, 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 dataset, 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 dataset, 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.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.
| 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 |
| Scanner and Nonscanner (Scanner-dependent) |
Original Nonscanner (Scanner-independent) |
Newer Nonscanner (Scanner-independent) |
Total Solor Irradiance | |
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| Temporal Coverage | 11/1984 - 02/1990: | 11/1984 - 11/1995: | 11/1984 - 09/1999: | 10/1984 - 03/2003: |
| Data Sets |
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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.
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 |
| 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 |
