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MERIS black-sky albedo database

 
   
 
European Space Agency

page last modified:
16 June 2017
     

Christoph Popp has created a surface albedo climatology based on MERIS Albedomap data. For each MERIS channel the black-sky albedo (BSA) for all months is stored in a zip file. There are also files with quality flags (one for each month). The meaning of the values of the flags are:
 
0: snow- and ice-free land pixels
1-100: snow fraction (compiled from the MODIS MOD10 - Snow cover product)
240: water pixels filled with GOME-1 surface LER values
250: filled with value from closest month
 
Note that water pixels at 865 and 885 nm are not filled with GOME-1 surface LER values since the closest wavelength band available from GOME-1 is the one at 772 nm. An alternative for this would be the SCIAMACHY surface LER database, which does provide wavelength bands near these wavelengths. Additionally, this database offers a higher quality and additional wavelength bands that are closer to the MERIS bands. If wavelengths above 772 nm are not required, a better alternative for water pixel replacement would be the GOME-2 surface LER database.

An IDL routine is available which can read the files (returns albedo*1000 or the quality flag). A description for reading the data with Fortran can be found here.

Validation of the MERIS BSA climatology based on direct intercomparison with the SCIAMACHY surface LER climatology is described here.

If you're planning to use this database, please refer to the scientific paper describing the database, which is available here.


Some examples of the database:

MERIS albedo over land, GOME albedo over sea.
Month: August
MERIS albedo over land, no values over sea.
Month: August
MERIS quality flags.
Month: August


Archive:

The MERIS BSA database is available in the form of separate zip files for each of the thirteen wavelength bands:

  • merisTOTL[mm]_[wvl].dat
    == monthly black-sky albedo (land) or minimum LER (sea) values for month [mm] and wavelength [wvl] nm

Additionally, there are also FLAG files quality_flags_[mm].dat for the TOTL files, one for each month and valid for all wavelength bands. These are zipped together in a 14-th file. The reason for splitting up the database is to minimise the download effort in case you do not need the data of all wavelength bands.

MERIS wavelength GOME-1 wavelength Monthly data files (zipped) Monthly GIF images (zipped)
412 nm 416 nm meris_bsa_412.zip zip file of images
442 nm 440 nm meris_bsa_442.zip zip file of images
490 nm 494 nm meris_bsa_490.zip zip file of images
510 nm 494 nm meris_bsa_510.zip zip file of images
560 nm 555 nm meris_bsa_560.zip zip file of images
620 nm 610 nm meris_bsa_620.zip zip file of images
665 nm 670 nm meris_bsa_665.zip zip file of images
681 nm 670 nm meris_bsa_681.zip zip file of images
707 nm 670 nm meris_bsa_707.zip zip file of images
754 nm 758 nm meris_bsa_754.zip zip file of images
775 nm 772 nm meris_bsa_775.zip zip file of images
865 nm -- meris_bsa_865.zip zip file of images
885 nm -- meris_bsa_885.zip zip file of images
Quality flags   quality_flags.zip  
NOTE: Use  "unzip"  or  "gunzip -S .zip"  to unzip.

Documentation:

  • C. Popp, P. Wang, D. Brunner, P. Stammes, Y. Zhou, and M. Grzegorski, MERIS albedo climatology for FRESCO+ O2 A-band cloud retrieval, Atmos. Meas. Tech., 4, 463-483, doi:10.5194/amt-4-463-2011, 2011.

  • 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.