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GOME-2 surface LER database

 
   
 
European Space Agency

page last modified:
21 April 2017
     

The GOME-2 surface LER database contains the Lambertian-equivalent reflectivity values at 21 one-nm wide wavelength bins between 335 and 772 nm. The Lambertian-equivalent reflectivities (LERs) were derived from GOME-2 data using the Doubling-Adding KNMI (DAK) polarised radiative transfer code. The model consists of an atmosphere for which Rayleigh scattering and ozone absorption is taken into account, and which is bounded below by a Lambertian surface. The surface LER is available for each month of the year and for the following wavelengths: 335, 340, 354, 367, 380, 388, 416, 425, 440, 463, 494, 510, 526, 546, 555, 564, 610, 640, 670, 758, and 772 nm -- a total of 21 wavelength bands. Next to this, we also provide a GOME-2 surface LER database which is based on PMD band measurements.


Some examples of the database:

Examples of the GOME-2 surface LER: dependence on the month of the year (left) and dependence on the wavelength (right).

Archive:

The following databases are available:

GOME-2_MetOp-A_MSC_025x025_surface_LER_v2.0.hdf5   (617 MB)

GOME-2_MetOp-B_MSC_025x025_surface_LER_v2.0.hdf5   (609 MB)

GOME-2_MetOp-A_PMD_025x025_surface_LER_v2.0.hdf5   (656 MB)

GOME-2_MetOp-B_PMD_025x025_surface_LER_v2.0.hdf5   (652 MB)

PLEASE NOTE THAT THESE ARE UNOFFICIAL RELEASES, NOT REVIEWED BY THE AC SAF. The last official AC SAF releases of the GOME-2A surface LER databases are available in the normal way via the AC SAF website, via the URL http://acsaf.org/datarecords/ler.html.


Most users will only be interested in the GOME-2A and GOME-2B surface LER databases that were based on Main Science Channel (MSC) observations. The wavelength bands (listed above) are more or less monochromatic (one nm wide) and suitable for the retrieval of most atmospheric species. The intrinsic resolution of the MSC-LER databases is 1°×1°, but increased to 0.25°×0.25° near coastlines. The spatial resolution of the database grid therefore is 0.25°×0.25°. Please note that the quality of the GOME-2A database is higher than that of GOME-2B database due to the higher amount of data that were available.

Next to the normal MSC-LER products, there are also GOME-2A and GOME-2B surface LER products based on the PMD bands. These PMD-LER products are mostly relevant to users that use GOME-2 PMD band measurements for their retrievals. Note that some discrepancies between the radiometric calibration of the main science channels and the PMD bands have been reported in the past [click]. The intrinsic resolution of the PMD-LER databases is 0.5°×0.5°, but increased to 0.25°×0.25° near coastlines. The spatial resolution of the database grid therefore is 0.25°×0.25°.

The format and the contents of these files are both explained here. The current version of the database is 2.0.





The GOME-2 surface LER databases are provided by KNMI in the framework of the EUMETSAT Satellite Application Facility on Atmospheric Composition Monitoring (AC SAF).


Data use / Citation:

The GOME-2 surface LER databases are free to use for commercial and non-commercial purposes. If you use any of the databases for a publication (research or otherwise), or for any other purpose, please refer to the following publication:

L.G. Tilstra, O.N.E. Tuinder, P. Wang, and P. Stammes, Surface reflectivity climatologies from UV to NIR determined from Earth observations by GOME-2 and SCIAMACHY, J. Geophys. Res. Atmos. 122, doi:10.1002/2016JD025940, 2017.

We request that you include the following acknowledgement: "We acknowledge the free use of the GOME-2 surface LER database provided through the AC SAF of EUMETSAT. The GOME-2 surface LER database was created by the Royal Netherlands Meteorological Institute (KNMI)."


Documentation:

  • L.G. Tilstra, O.N.E. Tuinder, P. Wang, and P. Stammes, Surface reflectivity climatologies from UV to NIR determined from Earth observations by GOME-2 and SCIAMACHY, J. Geophys. Res. Atmos. 122, doi:10.1002/2016JD025940, 2017.