ASCAT Scatterometer Calibration over the Ocean: Analysis of the 3-Dimensional Measurement Space

Abstract

A new scatterometer, the so-called Advanced scatterometer (ASCAT), onboard MetOp-A satellite was successfully launched on October 19 2006. During the commissioning phase one of the main goals is to accurately calibrate the instrument. The radar backscatter has been calibrated using three ground- based transponders only in February 2008. However, stable and good quality ASCAT winds are produced routinely at KNMI since March 2007, as the first MetOp-A geophysical product. This Ocean and Sea Ice Satellite Application Facility (OSISAF) wind product was established by exploiting the wind manifold in the 3-dimensional measurement space. Further verification of the ASCAT calibration over the ocean is done by comparing the backscatter measurements with backscatter values derived from collocated NWP winds