Surface Radiation Fluxes

The Downward Surface Shortwave Flux (DSSF) refers to the radiative energy in the wavelength interval [0.3 µm, 4.0 µm] reaching the Earth's surface per time and surface unit. It essentially depends on the solar zenith angle, on cloud coverage, and to a lesser extent on atmospheric absorption and surface albedo. DSSF fields are crucial for a wide number of applications involving scientific domains like weather forecast, hydrology, climate, agriculture and environment-related studies. In numerical weather prediction and general circulation models of the atmosphere, satellite-derived DSSF estimates can either be used as a control variable or as a substitute to surface radiation measurement networks.

Available Products:

• MDSSF: Instantaneous radiative energy in the shortwave domain reaching the surface derived from SEVIRI/MSG (superseded version)
• MDSSFTD: Instantaneous estimate of the total and the fraction of diffuse radiative energy in the shortwave domain reaching the surface derived from SEVIRI/MSG; demonstration product available for the Indian Ocean Data Coverage (IODC)
• MDIDSSF: Daily integration of the radiative energy in the shortwave domain reaching the surface derived from SEVIRI/MSG; demonstration product available for the Indian Ocean Data Coverage (IODC)

Available data formats:

• Geostationary/sinusoidal grid in HDF5
• Regular grid in NETCDF4

Data Server information:

• Product Output Format
• Data Server User Guide

Downward Surface Longwave Flux (DSLF) is the result of atmospheric absorption, emission and scattering within the entire atmospheric column and may be defined as the thermal irradiance reaching the surface in the thermal infrared spectrum (4-100 µm). In clear sky situations DSLF depends on the vertical profiles of temperature and gaseous absorbers (primarily the water-vapour followed by CO2, and others of smaller importance like O3, CH4, N2O and CFCs). However, DSLF is determined by the radiation that originates from a shallow layer close to the surface (about one third being emitted by the lowest 10 meters and 80% by the 500-meter layer). The cloud contribution mainly occurs in the atmospheric window (8-13 µm) and mainly depends on cloud base properties (height, temperature and emissivity).

Available Products:

• MDSLF: Instantaneous radiative energy in the longwave domain reaching the surface derived from SEVIRI/MSG; demonstration product available for the Indian Ocean Data Coverage (IODC)
• MDIDSLF: Daily integration of the radiative energy in the longwave domain reaching the surface derived from SEVIRI/MSG; demonstration product available for the Indian Ocean Data Coverage (IODC)

Available data formats:

• Geostationary/sinusoidal grid in HDF5
• Regular grid in NETCDF4

Data Server information:

• Product Output Format
• Data Server User Guide

The Net Surface Longwave Flux (DSLF) drives the processes of evaporation, photosynthesis, and heating of soil and air. Radiative processes in the Earth-atmosphere system are essential for maintenance of the atmospheric general circulation. Knowledge of the radiation budgets at the surface and top of atmosphere allows the determination of the radiative forcing of the atmosphere as well as the radiative heating of the surface. Furthermore, the surface net radiation plays a major role in the surface energy balance, which in turn controls near surface temperature and drives several of the biological and physical processes on Earth. The net longwave (NSLF) product is estimated from the downwelling longwave surface flux product (DSLF) and the all-weather LST (LST-AS), which is the main contributor to the upwelling longwave flux.

Available Products:

• MNSLF: Daily net energy at the surface in the longwave domain derived from SEVIRI/MSG;

Available data formats:

• Geostationary/sinusoidal grid in HDF5
• Regular grid in NETCDF4

Data Server information:

• Product Output Format
• Data Server User Guide