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TROPOMI surface LER & DLER database

European Space Agency


page last modified:
08 October 2021

The TROPOMI surface DLER database contains the Lambertian-equivalent reflectivity (LER) of the Earth's surface at 21 one-nm wide wavelength bins between 328 and 2314 nm. Next to the traditional non-directional LER field, the database contains the directionally dependent Lambertian-equivalent reflectivity (DLER) of the surface. In the DLER, the viewing-angle dependence of the surface reflectance, due to the BRDF of the surface, is taken into account, which improves the surface reflectance considerably, especially for the longer wavelengths.

The (D)LER albedo values were derived from TROPOMI data using the Doubling-Adding KNMI (DAK) polarised radiative transfer code. The model consists of an atmosphere for which Rayleigh scattering and ozone absorption are taken into account, and which is bounded below by a Lambertian surface. The surface (D)LER is available for each month of the year and for the following wavelengths: 328, 335, 340, 354, 367, 380, 388, 402, 416, 425, 440, 463, 494, 670, 685, 697, 712, 747, 758, 772, and 2314 nm. These wavelength bands are more or less monochromatic (one nm wide in most cases) and suitable as input for the retrieval of most atmospheric species. The resolution of the database grid is 0.125°×0.125°.


The following database based on TROPOMI observations is available:

TROPOMI_Sentinel-5P_0125x0125_surface_DLER_v0.7.nc   (14 GB)

Previous versions of the databases can be downloaded here.

The format and the contents of the files are explained here. The current version of the database is 0.7. This version is based on 36 months of TROPOMI data.

Origin / Creator:

The TROPOMI surface DLER database is provided by KNMI in the framework of the Sentinel-5p+ Innovation project led by ESA.

Data use / License / Citation:

The TROPOMI surface DLER database is free to use for commercial and non-commercial purposes. If you use the database for a publication (research or otherwise), or for any other purpose, please refer to the following publication:

L.G. Tilstra, TROPOMI ATBD of the directionally dependent surface Lambertian-equivalent reflectivity, KNMI Report S5P-KNMI-L3-0301-RP, Issue 1.1.0, May 12, 2021 (PDF)

We suggest that you include the following acknowledgement: "We acknowledge the free use of the TROPOMI surface DLER database provided through the Sentinel-5p+ Innovation project of the European Space Agency (ESA). The TROPOMI surface DLER database was created by the Royal Netherlands Meteorological Institute (KNMI)."


  • L.G. Tilstra, O.N.E. Tuinder, P. Wang, and P. Stammes, Directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface measured by the GOME-2 satellite instruments, Atmos. Meas. Tech. 14, 4219-4238, doi:10.5194/amt-14-4219-2021, 2021 (PDF)