Solar Radiation Database

The text on this page is taken from an equivalent page of the IEHIAS-project.

The Solar Radiation Database (SoDa) Service is a web-application designed to answer the needs of industry and research for information on several solar resources. A number of databases and data sets relating to long-term time-series of irradiance or irradiation (also called the shortwave downwelling radiation), temperature, rainfall, longwave radiation, Linke turbidity factor, atmospheric turbidity, clear-skies properties, PAR (photosynthetically active radiation), spectral distribution are included.

From the homepage, all of the following databases are accessible through the “Service” item. All the databases work with a similar interface. Common input data are :

• Longitude and latitude in degrees and decimals of degrees. Western longitudes and northern latitudes are positive. A search can be made by cities or using a map.
• Altitude above sea level in meter. If omitted, the mean altitude of the 5' grid is taken.
• Units.
• Format of results: html or csv. However, it is difficult to copy the results from the web page to another file.

Some of the database are freely accessible while some require registration.

An example of a SoDa entry page.

Monthly averages of daily global radiation resulting from interpolation of measurements made in the meteorological network

This resource provides monthly values of global radiation for the whole world. Monthly values are taken from the climatological database METEONORM. The error of the interpolation depends on the density of the network. In Europe, with a dense network the error is about 6%.

This is a free database.

Monthly averages of air temperature resulting from interpolation of measurements made in the meteorological network

The resource provides monthly values of ambient temperature for the whole world. Monthly values are taken from the climatological database METEONORM, which is based on WMO CLINO 1961-90 (1998). Hourly values of ambient temperature are interpolated according SODA interpolation task. The data of the meteorological stations are interpolated on-line. The interpolation has an rmse of about 2°C for monthly values.

This is a free database.

Monthly values of Linke turbidity factor

This resource serves monthly climatological values of Linke turbidity for air mass 2, water vapour, Angstroem beta and stratospheric ozone on a global scale. It calculates the monthly mean values for any geographical location, any month and any elevation. The altitude of the geographical site of simulation can be either extracted from the orography resource (if set to 0) or forced by the user by inputting a value greater than or equal to 1. Unit is meter. The orography resource has a grid cell of 5' of arc angle and uses the data base TerrainBase (TerrainBase, Worldwide Digital Terrain Data. Documentation Manual, CD-ROM Release 1.0, April 1995. NOAA, National Geophysical Data Center, Boulder, Colorado, USA). The Linke turbidity presented here is based on several global information from satellites like global clear sky radiation (SRB), precipitable water vapour (NVAP), aerosol optical depth (pathfinder) and ground information about turbidity from radiation or aerosol measurements (AERONET). Turbidity has been calculated with beam or global radation measurements at the ground with help of the ESRA clear sky radiation model. Satellite and ground information have been fitted together. The coverage is worldwide. The way of constructing the database is explained on the Web site HelioClim. The other atmosphere parameters: Water vapour (WV) or total precipital water is taken from NVAP and corresponds to mean values of 1988-97.

This is a free database.

Degree-days below a given temperature

Degree days below a temperature (also called Heating degree days) correspond to the cumulative number of degrees by which the mean daily temperature falls below a given temperature called the "base temperature". Base temperatures ranging from 12°C to 22°C are available. The heating degree days for a particular day are based on the average temperature of the day (the sum of the high and low temperatures divided by two). If the average temperature is above the base temperature, there are no heating degree days that day. If it is less than the base temperature, the base temperature is subtracted from it to give the number of heating degree days. The Satel-Light server delivers daylight and solar radiation information over Western and Central Europe with a high spatial and temporal resolution (every 5 km, every half-hour).

This is a free database.

Degree-days above a given temperature

Degree days above a temperature (also called Cooling degree days) correspond to the cumulative number of degrees by which the mean daily temperature rises above a given temperature called the "base temperature". Base temperatures ranging from 5°C to 25°C are available. The cooling degree days for a particular day are based on the average temperature of the day (the sum of the high and low temperatures divided by two). If the average temperature is less than the base temperature, there are no cooling degree days that day. If it is above the base temperature, it is subtracted from the base temperature to give the number of cooling degree days. The Satel-Light server delivers daylight and solar radiation information over Western and Central Europe with a high spatial and temporal resolution (every 5 km, every half-hour).

This is a free database.

Frequency of types of sky

The frequency of each of these sky conditions at a given location indicates how each is representative of the climate at that location.

Three sky types are available: cloudy, intermediate and sunny, for sites in Western and Central Europe. The frequencies are based on the analysis of the images produced by the METEOSAT satellite every half hour, for five years: 1996 to 2000. The sky classification is based on the range of brightness values in the METEOSAT image: cloudy corresponds to the brightest values, sunny corresponds to the darkest values, intermediate is in between. The frequencies are available for two daily schedules: sunrise to sunset and 8:00 to 18:00 (local time) which corresponds to the operating hours of most office buildings.

This is a free database.

UV radiation – Europe

The resource serves monthly, daily or hourly values of UV clear and all sky radiation on a global scale. Hourly values are calculated and summed to daily or monthly values for Europe. Daily values of global radiation are taken from MARS database.

The data in the MARS database is interpolated from the most suitable meteorological stations to reflect the daily global radiation for a 50 by 50 km grid. The data are used primarily for crop yield modelling.

The inout data are:

• Spectral part of UV: UVA, UVB or Erythemal clear sky (cs) and all sky (as) radiation.
• Ozone [DU] (fix value); if not set, mean values are taken.
• Angstrom Beta (fix value); if not set, mean values are taken.
• Water vapour [cm] (fix value); if not set, mean values are taken.
• Type of ground for albedo

This is a free database.

Daily Values of UV Radiation since 1985 - Europe, Africa (ESRA model)

The resource serves monthly, daily or hourly values of UV clear and all sky radiation on a global scale. Hourly values are calculated and summed to daily or monthly values.

Input variables are

• Spectral part of UV: UVA, UVB or Erythemal clear sky (cs) and all sky (as) radiation.
• Ozone [DU] (fix value); if not set, mean values are taken.
• Angstrom Beta (fix value); if not set, mean values are taken.
• Water vapour [cm] (fix value); if not set, mean values are taken.
• Angstrom Beta (optional).
• Ozone (optional).
• Water vapour (optional).
• Linke turbidity for airmass 2 (optional).
• Day: Day of month (if output of only one day is wished).

Hourly Values of Solar Radiation - Europe – Africa

This database provides data on:

• time-series of radiation values: from hourly (only HelioClim-2) to monthly values. Values are irradiance in W/m2 as well as irradiation in Wh/m2 and J/cm2
• irradiance at top of atmosphere
• irradiance under clear-sky
• uncertainty values
• information on the number of data used to compute the radiation value

Data are provided by satellite HelioClim-2 from February 2004 onwards. Satellite data are received at Ecole des Mines de Paris by the means of a receiving station and are processed immediately. They are available 2-3 minutes after end of acquisition. For legal reasons, they are disseminated only 24 hours after. Data from HelioClim-1 are used for the period 1985-2005.

The accuracy has been assessed by comparisons with measurements performed in several stations of the WMO radiometric networks in Europe and Africa. The natural variability of the radiation should be removed from the values below (approx. 10-15 %) to evaluate the accuracy of the database.

This is not a free database.

Daily Values of Solar Radiation - Europe – Africa

This database provides data on:

• time-series of radiation values: from hourly (only HelioClim-2) to monthly values. - -Values are irradiance in W/m2 as well as irradiation in Wh/m2 and J/cm2.
• irradiance at top of atmosphere
• irradiance under clear-sky
• uncertainty values
• information on the number of data used to compute the radiation value

Data are provided by satellite HelioClim-2 from February 2004 onwards. Satellite data are received at Ecole des Mines de Paris by the means of a receiving station and are processed immediately. They are available 2-3 minutes after end of acquisition. For legal reasons, they are disseminated only 24 hours after. Data from HelioClim-1 are used for the period 1985-2005.

The accuracy has been assessed by comparisons with measurements performed in several stations of the WMO radiometric networks in Europe and Africa. The natural variability of the radiation should be removed from the values below (approx. 10-15 %) to evaluate the accuracy of the database.

This is not a free database.

NCEP/NCAR reanalysis daily values for radiation, temperature, precipitations

This database provides data from the archives of NCEP/NCAR (National Center for Environmental Predictions/ National Center for Atmospheric Research USA) from 1958. Available data are:

• downward shortwave radiation
• net shortwave radiation
• downward longwave radiation
• net longwave radiation
• average temperature
• minimum temperature
• maximum temperature
• precipitation rate

Data from this reanalysis can also be obtained through here.

Mars database of solar radiation – Europe

This database provides point data of daily irradiation from 1975 to 2004 for areas of 50*50km2. Values are computed from interpolation of the results observed by the meteorological networks.

Forecasting meteorological parameters - Grid size 21 km - Europe

This service provides weather forecasts of several meteorological parameters, including radiation components, for 3 days every 3-hours. They are provided by the Departments of Physics of the Universities of Genova and Bologna, Italy, using BOLAM model for numerical weather prediction.

Forecasting meteorological parameters - Grid size 10 km - Italy-centered region

This service provides weather forecasts of several meteorological parameters, including radiation components, for 3 days every 3-hours. They are provided by the Departments of Physics of the Universities of Genova and Bologna, Italy, using BOLAM model for numerical weather prediction.