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QDOAS Projects Properties : Selection page

This page is dedicated to the selection of spectra to browse or to analyse.  The selection of spectra can be made on :

SZA
specify a range of solar zenith angles and a step in degrees;
Spectra No
specify a range of record numbers;
Cloud fraction
for satellite measurements, specify a range of cloud fraction (0..1). Until now, only the GOME-2 file format includes information on the cloud fraction.
Geolocation
for satellite measurements, selection of pixels based on the geolocation of measurements

To browse or to analyse all spectra of a file without any constrain, keep the fields initialized as shown in the figure above (default options).

Geolocation

Some applications just need satellite overpasses over a list of ground-based stations or above specific regions (satellite validation activities for example). The geolocation frame gives three possibilities to select pixels over specific locations :

Circle
select pixels within a circle whose the radius is given in kilometers and whose the center could be the position of a station defined by its latitude and longitude.
Rectangle
select pixels above a specific region bounded by the limits in longitude and latitude given in degrees (0..360° or -180..180 for the longitude according to the satellite file format).
Sites
select pixels within multiple circles with radius given in kilometers and center position determined by the longitude and the latitude of the observation sites defined in the Sites tab page (see the Output page for the automatic creation of the output file name)

 

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