Solar radiation enters the Earth's atmosphere with a portion being scattered by clouds and aerosols.

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at the NASA Langley Research Center

SSE Data and Information Page

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Surface meteorology and Solar Energy (SSE)
Data and Information

SSE-GIS v1.03 Web Mapping Application Now Available

The Release 6.0 Surface meteorology and Solar Energy (SSE) data set contains parameters formulated for assessing and designing renewable energy systems. This latest release contains new parameters based on recommendations by the renewable energy industry and it is more accurate than previous releases. Global, regional and site specific radiation and meteorological data allow quick evaluation of potential renewable energy projects for any region of the world. The SSE data set is formulated from NASA satellite- and reanalysis-derived insolation and meteorological data for the 22-year period July 1983 through June 2005. Results are provided for 1° latitude by 1° longitude grid cells over the globe.

 

Please consider joining our SSE mailing list. Since SSE is an active site, we perform regular updates and revisions. By joining the mailing list, we will inform you of changes to the web site that might impact the use of the data.

 

If you have SSE questions or comments concerning the retrieval of data from this SSE web site, or the data parameters provided, please contact us.


Data Subsetter Description Order

Single Location

Tables of ALL SSE parameters for a single site.

Regional Location

Subsets of data by region

Interannual Variability

Monthly and annual averages by year and for a series of years.

Global Data

Text files of monthly averaged data for the entire globe. Some annual averages or annual sums are included

Daily Data

Time series plots and data lists of Insolation and Air Temperature for a single site


Data Support Tools Description Order

RETScreen International

A collaboration with the CanmetENERGY research centre in Varennes, Quebec has produced satellite data output useful to users of the RETScreen® International Clean Energy Project Analysis Software. RETScreen® International can be obtained free of charge from CanmetENERGY.

HOMER

The Hybrid Optimization Model for Electric Renewables ( HOMER ) is used for designing standalone electric power systems that employ some combination of wind turbines, photovoltaic panels, or diesel generators to produce electricity.

Solar Cooking

Average Insolation (kWh/m2/day)

Amount of electromagnetic energy (solar radiation) incident on the surface of the earth. Also referred to as total or global solar radiation.

 

Midday insolation (kWh/m2/day)

Average insolation available within 1.5 hours of Local Solar Noon.

 

Clear sky insolation (kWh/m2/day)

Average insolation during clear sky days (cloud amount < 10%).

 

Clear sky days (days)

Number of clear sky days (cloud amount < 10%).

Sizing and Pointing of Solar Panels and for Solar Thermal Applications

Insolation on horizontal surface (kWh/m2/day)

Amount of electromagnetic energy (solar radiation) incident on the surface of the earth. Also referred to as total or global solar radiation. The average and percent difference minimum and maximum are given.

 

Diffuse radiation on horizontal surface (kWh/m2/day)

Amount of electromagnetic energy (solar radiation) incident on the surface of the earth under all-sky conditions with direct radiation from the Sun's beam blocked by a shadow band or tracking disk at the Earth's surface.

 

Direct normal radiation (kWh/m2/day)

Amount of electromagnetic energy (solar radiation) at the Earth's surface on a flat surface perpendicular to the Sun's beam with surrounding sky radiation blocked.

 

Insolation at 3-hourly intervals (kW/m2)

Amount of electromagnetic energy (solar radiation) incident on the surface of the earth.

 

Insolation clearness index (dimensionless)

Fraction of insolation at the top of the atmosphere which reaches the surface of the earth.

 

Insolation normalized clearness index (dimensionless)

Zenith angle-independent expression of the insolation clearness index.

 

Clear sky insolation (kWh/m2/day)

Average insolation during clear sky days (cloud amount < 10%).

 

Clear sky insolation clearness index (dimensionless)

Fraction of insolation at the top of the atmosphere which reaches the surface of the earth during clear sky days (cloud amount < 10%).

 

Clear sky insolation normalized clearness index (dimensionless)

Zenith angle-independent expression of the clear sky insolation clearness index.

Solar Geometry

Solar Noon (GMT time)

The time when the sun is due south in the northern hemisphere or due north in the southern hemisphere.

 

Daylight Hours (hours)

Time between sunrise and sunset.

 

Daylight average of hourly cosine solar zenith angles (dimensionless)

The average cosine of the angle between the sun and directly overhead during daylight hours.

 

Cosine solar zenith angle at mid-time between sunrise and solar noon (dimensionless)

Approximate monthy average ratio of horizontal surface solar beam radiation to direct normal radiation.

 

Declination (degrees)

The angular distance of the sun north (positive) or south (negative) of the equator.

 

Sunset Hour Angle (degrees)

The angle that the earth has rotated between the time of solar noon and sunset.

 

Maximum solar angle relative to the horizon (degrees)

The maximum vertical angle of the sun above the horizon.

 

Hourly solar angles relative to the horizon (degrees)

The vertical angle of the sun above the horizon.

 

Hourly solar azimuth angles (degrees)

The arc of the horizon measured clockwise from true north, to the point where a vertical circle through the sun intersects the horizon.

Tilted Solar Panels

Radiation on equator-pointed tilted surfaces (kWh/m2/day)

Radiation on tilted surfaces is calculated from the monthly average insolation on a horizontal surface. Tilt angles are 0, latitude - 15, latitude, latitude + 15, 90, and the optimum angle. The optimum angle provides the monthly averaged maximum radiation.

 

Minimum radiation for equator-pointed tilted surfaces (kWh/m2/day)

Radiation on tilted surfaces is calculated from the monthly minimum insolation on a horizontal surface. Tilt angles are 0, latitude - 15, latitude, latitude + 15, 90, and the optimum angle. The optimum angle provides the monthly averaged maximum radiation.

 

Maximum radiation for equator-pointed tilted surfaces (kWh/m2/day)

Radiation on tilted surfaces is calculated from the monthly maximum insolation on a horizontal surface. Tilt angles are 0, latitude - 15, latitude, latitude + 15, 90, and the optimum angle. The optimum angle provides the monthly averaged maximum radiation.

Sizing Battery or other Energy-storage Systems

Minimum available insolation as % of average values over consecutive-day period (1, 3, 7, 14, and 21 days) (dimensionless)

This parameter is based on minimum consecutive-day insolation over various numbers of days within the month.

 

Horizontal surface deficits below expected average values over consecutive-day period (1, 3, 7, 14, and 21 days) (kWh/m2)

Deficits below expected average values over consecutive-day period.

 

Equivalent number of NO-SUN days over consecutive-day period (1, 3, 7, 14, and 21 days) (days)

Hypothetical number of days for which no solar insolation is available.

Sizing Surplus-product Storage Systems

Available surplus as % of average values over consecutive-day period (1, 3, 7, 14, and 21 days) (dimensionless)

Available surplus as % of average values over consecutive-day period.

Cloud Information

Daylight cloud amount (percent)

Percent of cloud amount during daylight within a region.

 

Cloud amount at 3-hourly intervals (percent)

Percent of cloud amount within a region.

 

Frequency of cloud amount at 3-hourly intervals (percent)

Percent of time the cloud amount is less than 10%, between 10 - 70%, and greater than 70% within a region.

Meteorology (Temperature)

Air Temperature (° C)

 

Daily Temperature Range (° C)

Difference between the average daily maximum and average daily minimum.

 

Cooling Degree Days above 18° C (degree days)

The monthly accumulation of degrees when the daily mean temperature is above 18° C.

 

Heating Degree Days below 18° C (degree days)

The monthly accumulation of degrees when the daily mean temperature is below 18° C.

 

Arctic Heating Degree Days below 10° C (degree days)

The monthly accumulation of degrees when the daily mean temperature is below 10° C.

 

Arctic Heating Degree Days below 0° C (degree days)

The monthly accumulation of degrees when the daily mean temperature is below 0° C.

 

Earth Skin Temperature (° C)

 

Daily Mean Earth Temperature minimum, maximum and amplitude (° C)

Minimum: 22-year average of the minimum daily mean earth temperature for each month.

Maximum: 22-year average of the maximum daily mean earth temperature for each month.

Amplitude: One half of the difference between the average daily earth temperature minimum and maximum.

 

Frost Days (days)

The number of days for which the temperature falls below 0 degrees Celsius.

 

Dew/Frost Point Temperature (° C)

Temperature at which air is saturated with water vapor.

Meteorology (Wind)

Wind speed at 50 m (m/s)

The average and percent difference minimum and maximum are given.

 

Percent of time for ranges of wind speed at 50 m (percent)

Percentage [frequency] of time that wind speed is in each range (0-2, 3-6, 7-10, 11-14, 15-18, 19-25 m/s).

 

Wind Speed at 50 m at 3-hourly intervals (m/s)

 

Wind Direction at 50 m (degrees)

 

Wind Direction at 50 m at 3-hourly intervals (degrees)

 

Wind Speed at 10 m for terrain similar to airports (m/s)

 

Wind Speed adjustments for height and vegetation type (m/s)

Wind speeds at 50 m may be adjusted to heights from 10 to 300 meters using the Gipe power law. Wind speeds may be adjusted for different terrain by selecting from 17 vegetation types.

Meteorology (Other)

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Supporting Information

Top-of-atmosphere insolation (kWh/m2/day)

Amount of electromagnetic energy (solar radiation) incident at the top of the atmosphere.

 

Surface Albedo (dimensionless)

Fraction of insolation reflected by the surface of the earth.

Read software unavailable

General Documentation Relevant Links
Frequently Asked Questions (FAQs)

Data Citation

 

SSE is supported through the Prediction of Worldwide Energy Resource (POWER) project under the NASA Applied Sciences Program within the Earth Science Division of the Science Mission Directorate. When POWER data products are used in a publication, we request the following acknowledgment be included:  "These data were obtained from the NASA Langley Research Center Atmospheric Science Data Center Surface meteorological and Solar Energy (SSE) web portal supported by the NASA LaRC POWER Project."   Read more on citing data

 

Partners & Industry Contributors

 

The following organizations have made significant technical contributions to the success of the SSE project:

 

  • BP Solar International - Provided information on present industrywide methods used to estimate diffuse and direct normal radiation.
  • GPCo - Provided independent assessment of wind data.
  • National Renewable Energy Laboratory (NREL) - Provided the WRDC ground site insolation data that are incorporated into the SSE web site as part of an Interagency Agreement.
  • Natural Resources Canada (NRCan) CANMET Energy Technology Centre (CETC) - Varennes - Provided temperature, wind, humidity, and insolation data from 1000+ sites to verify SSE data.
  • Numerical Logics, Inc. - Provided independent assessment of accuracy results.
  • Solar Energy International (SEI) - Participated in a cost-sharing partnership, which involves the Center for Renewable Energy and Sustainable Technology (CREST). Both companies advised on the renewable energy industry, and develop applications of the data.
  • Solar Household Energy, Inc. - Advised on SSE web site development.
  • The State University of New York at Albany, Atmospheric Sciences Research Center - Provided models for diffuse and direct normal radiation calculations.