GERB Station Data

Introduction

At the end of the RMIB GERB processing, the data in the SHI images (3*3 SEVIRI pixel resolution) is extracted over pre-defined pixels. These pixels correspond to the positions of ground measurement stations in the GERB field-of-view such as BSRN sites. This extraction is expected to be useful in the frame of the validation of the GERB processing and to validate surface radiation budget retrieval from GERB data.

Listing of stations

The extraction is currently performed over the following stations:

Station Country Lat Lon

Achern Germany 48.638 8.066
Balbina Brazil -3.2 -60.0
Bermuda USA-sponsored 32.3 -64.3
Budapest Hungary 47.8 19.1
Cabauw The Netherlands 51.97 4.93
Cambourne UK 50.0 -5.0
Carpentras France 44.0 5.0
Chilbolton UK 51.1445 -1.437
De-Aar South Africa -30.7 24.0
Florianopolis Brazil -27.5 -48.5
Hornisgrinde Germany 48.604 8.204
Heselbach Germany 48.539 8.395
Ilorin Nigeria 8.5 4.6
Lindenburg Germany 52.3 14.1
Niamey Niger 13.477 2.176
AMMA-anc Niger 13.522 2.632
Palaiseau France 48.713 2.204
Payerne Switzerland 46.8 6.9
Riyadh Saudi Arabia 24.7 48.8
Sede-Boqer Israel 30.9 34.8
Tamanrasset Algerie 22.78 5.85
Toravere Estonia 58.3 26.5
Uccle Belgium 50.8 4.35
Valencia Spain 39.57 -1.29

Files Format

For each station, a monthly ASCII file is created (for example Uccle_200402.txt for February 2004 at the Uccle station). The file contains a header followed by the 15' data organized in line. The file looks like:

# Station: Valencia
# position : lat=39.570 lon=-1.290 (line=187.822,column=606.480)
# nearest pixel : lat=39.549 lon=-1.342 (line= 188,column= 606)
# Viewing zenith angle=46.000000 , viewing azimuth angle=178.000000
#
# time flux_s flux_t rad_s rad_t c_sw c_lw cc ca cp sz ra hdf_file
20040219075510 81.00 230.75 97.25 371.75 1 3 -1 -1 -1 80 117 # G2_SEV1_L20A_H_20040219_074500_V002.hdf
20040219081010 94.00 229.25 120.00 369.50 7 -1 -1 -1 -1 77 119 # G2_SEV1_L20A_H_20040219_080000_V002.hdf
20040219082510 107.00 235.25 144.25 379.25 3 1 0 0 0 74 122 # G2_SEV1_L20A_H_20040219_081500_V002.hdf
20040219084010 128.00 232.25 178.50 374.25 5 0 0 0 0 72 125 # G2_SEV1_L20A_H_20040219_083000_V002.hdf
20040219085510 134.00 229.75 194.50 370.50 8 -2 0 0 0 70 128 # G2_SEV1_L20A_H_20040219_084500_V002.hdf
20040219091010 149.50 228.00 214.25 367.25 5 0 22 14 0 67 131 # G2_SEV1_L20A_H_20040219_090000_V002.hdf
20040219092510 169.75 234.00 253.00 377.50 5 1 11 11 0 65 134 # G2_SEV1_L20A_H_20040219_091500_V002.hdf
...
...

The header gives:

the positions of the station (lat-lon and coordinates in the ARCH field-of-view)

the positions of the nearest pixel (lat-lon and coordinates in the ARCH field-of-view)

the viewing angle for the pixel

the viewing azimuth angle for this pixel

The different columns of data provide respectively:

Time (UTC) of acquisition at the station [YYYYMMDDhhmmss],

solar flux [W/m2],

thermal flux [W/m2],

solar radiance [W/m2/sr],

thermal radiance [W/m2/sr],

shortwave correction factor [%],

longwave correction factor [%],

cloud cover [%],

cloud amount [%],

cloud phase [%],

solar zenith angle [°],

relative azimuth angle [°],

original file name.

Remarks:

When a quantity is not available (for example the cloud retrieval during the night) the quantity is set to -1.0.

The user must be aware that the data files are not sorted chronologically.

For more information about the meaning of these different numbers see GERB Content Description.

Details of the BSRN site are at: http://bsrn.ethz.ch

Station data access

The station data are available for download on the ROLSS FTP site provided you are a registered GERB data user (you need a username and password to login). The station files are in the following ROLSS directories:

cd G2/SEV1/G2_SEV1_L20A_H_STATION before May 2007
cd G1/SEV2/G1_SEV2_L20A_H_STATION after May 2007

For more information / addition of station

For additional information or to add new locations in the list, please email:

To : Nicolas.Clerbaux@oma.be

CC : gerb@oma.be