Show simple item record

contributor authorBréon, François-Marie
contributor authorColzy, Stéphane
date accessioned2017-06-09T14:07:00Z
date available2017-06-09T14:07:00Z
date copyright1999/06/01
date issued1999
identifier issn0894-8763
identifier otherams-12725.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4148096
description abstractThis paper describes the cloud screening algorithms that have been developed for the processing of Polarization and Directionality of the Earth Reflectances (POLDER) measurements over land surfaces. Four tests are applied to the measurements. The first one is a threshold on the 0.44-?m reflectance after atmospheric correction. The second one is similar but with a smaller threshold and is applied only over targets with significant spectral variation. The third one compares the surface pressure to an estimate derived from two POLDER channels centered on an oxygen absorption band. The fourth one makes use of POLDER polarization capabilities and seeks the presence of a rainbow generated by water clouds. The performance of the method is evaluated using a large dataset of nearly coincident POLDER measurements and surface observations of cloud cover. The validation dataset is fully independent of the spaceborne measurements and allows the sampling of a wide range of situations. The results demonstrate the capability of the algorithm to distinguish clear and cloudy pixels, although a large fraction of pixels with a small cloud cover are incorrectly declared clear. This may be due in part to the different field of view of the spaceborne and surface observations. For a given cloud cover, the detection is less efficient for high clouds than for low- or medium-altitude clouds, which may result from their lower-optical thickness.
publisherAmerican Meteorological Society
titleCloud Detection from the Spaceborne POLDER Instrument and Validation against Surface Synoptic Observations
typeJournal Paper
journal volume38
journal issue6
journal titleJournal of Applied Meteorology
identifier doi10.1175/1520-0450(1999)038<0777:CDFTSP>2.0.CO;2
journal fristpage777
journal lastpage785
treeJournal of Applied Meteorology:;1999:;volume( 038 ):;issue: 006
contenttypeFulltext


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record