Cermak, J. & Bendix, J. (2007): <b>Dynamical nighttime fog/low stratus detection based on Meteosat SEVIRI data: A feasibility study</b>. <i>Pure and Applied Geophysics</i> <b>164</b>(6), 1179-1192.
Resource Description
Title:
Dynamical nighttime fog/low stratus detection based on Meteosat SEVIRI data: A feasibility study
FOR816dw ID:
105
Publication Date:
2007-06-08
License and Usage Rights:
PAK 823-825 data user agreement. (www.tropicalmountainforest.org/dataagreementp3.do)
Resource Owner(s):
Individual:
Jan Cermak
Contact:
email:
webmaster <at> lcrs.de
Individual:
Jörg Bendix
Contact:
email:
bendix <at> staff.uni-marburg.de
Deutschhausstraße 12
Room No. 02 A 48
35032 Marburg
Faculty of Geography
Germany
Abstract:
Automated detection of fog and low stratus in nighttime satellite data has been implemented on the basis of numerous satellite systems in past decades. Commonly, differences in small-droplet emissivities at 11?m and 3.9?m are utilized. With Meteosat SEVIRI, however, this method cannot be applied with a fixed threshold due to instrument design: The 3.9?m band is exceptionally wide and overlaps with the 4?m CO2 absorption band. Therefore, the emissivity difference varies with the length of the slant atmospheric column between sensor and object. To account for this effect, the new technique presented in this paper is based on the dynamical extraction of emissivity difference thresholds for different satellite viewing zenith angles. In this way, varying concentrations of CO2 and column depths are accounted for. The new scheme is exemplified in a plausibility study and shown to provide reliable results.
Keywords:
| low stratus | fog | satellite retrieval | meteosat SEVIRI | CO2 absorption | limb effect |
