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    24-Jul-2014
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4.4 Main MWR Level 1b algorithms

Question 4.18 : How is MWR data from one channel aligned to the data from the second channel?

In order to obtain coherent geophysical data, it is necessary to combine the observations of the two channels, pointing to different locations of the surface due to their different off-nadir angles, when available over the same spot.

This is done during the Level 1b processing in the so-called alignment processing algorithms.

On EnviSat, the second channel (at frequency 36.5 GHz) is looking forward, and therefore, certain (later in time) measurement of Channel 1, is searched such that both channels measurements are referring to the same point on ground.

This is done by considering the time difference of each channel sounding from nadir, considering the actual velocity and altitude of the satellite at each point.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry