Emissivity/BRDF data

Sources of Emissivity and Reflectance Data for RTTOV Users

Land surface emissivity and BRDF atlases are available with RTTOV itself. In the latest version of RTTOV the following atlases are available:

  • CMS BRDF atlas. Wavelength range: 0.4 – 2.6µm. Spatial resolution: 0.1 degrees lat/lon.
  • University of Wisconsin/CIMSS high resolution IR emissivity atlas. Wavelength range: 3.7 – 14.3µm. Spatial resolution: 0.1 degrees lat/lon in RTTOV dataset (native atlas resolution is 0.05 degrees).
  • CAMEL IR emissivity atlas. Wavelength range: 3.7 – 14.3µm. Spatial resolution: 0.05 degrees lat/lon.
  • TELSEM2 atlas and interpolator for MW sensors. Frequency range: 10 – 700 GHz. Spatial resolution: 0.25 degrees lat/lon (can optionally average emissivities over larger footprints).
  • CNRM MW atlas. This atlas consists of emissivity datasets for specific instruments: AMSU/MHS, SSMI/S, ATMS. Spatial resolution: 0.25 degrees lat/lon. ATMS data are also available at 0.5 degrees which reduces the number of data gaps.

More information on each of these atlases is available in the latest RTTOV user guide which also provide references for each one. The atlas data files can be downloaded here.

The following page is designed to provide information and web links to sources of IR and MW emissivity information which are suitable for input to RTTOV. This is in response to specific user feedback given in the NWP working group of the International TOVS Working Group.

Specifically information about sources of emissivity atlases and models is provided for 1-300 GHz, 1-15µm. Standard input can be considered to be surface skin temperature, soil moisture, sea ice fraction, sea ice type, snow cover.

The following sources are separated by spectral range (infrared and microwave) and further into atlases and models (links to old site):