Improvement of RapidScat and HSCAT wind quality control

• Main Authors: Lin, Wenming, Portabella, Marcos, Stoffelen, Ad, Verhoef, Anton, King, Gregory P.
• Format: Conference Object
• Language: unknown
• Published: European Space Agency 2016
• Subjects: Sea ice
• Online Access: http://hdl.handle.net/10261/161911

2016 European Space Agency (ESA) Living Planet Symposium, 9-13 May 2016, Prague, Czech Republic This paper reviews several wind quality-sensitive parameters derived from Ku-band scatterometer data. The objective is to assess their sensitivity to wind data quality in order to optimize the quality control (QC) for Ku-band scatterometers. The current scatterometer wind data processor uses the inversion residual or maximum likelihood estimator (MLE) value in QC. A large inconsistency between the measured backscatter set andthe geophysical model function (GMF) results in a largeMLE value, which indicates geophysical conditions other than those modeled by the wind GMF, such as rain,sea ice, highlocal wind variability,orconfused sea state.Therefore, the MLE value provides a good indication of the quality of the retrieved winds. Besides, an image processing technique, known as Singularity Analysis (SA), has been recently proposed as a complementaryQC tool to the current Advanced Scatterometer (ASCAT) MLE-based QC. In general, MLE is a proxy for sub- wind vector cell (WVC) wind variability, where large positive MLEs are usually found near (gust) fronts, squall lines, and convective systems. The SA-derived singularity exponent (SE) is based on spatial derivatives and therefore mostly represents the inter-WVC variability. By using a spatial filter approach similar to the SE derivation, one can also study the inter-WVC variability with the spatially-averaged MLE, which may further improve the wind quality control. A comprehensive wind quality assessment is carried out forthe ongoing Ku-band rotating pencil-beam scatterometers, namely RapidSCAT installed on the International Space Station and HSCAT onboard the Chinese HY-2A satellite. Since ASCAT QC near rain (< 1%) has been investigated recently and the C-band ASCAT sensitivity to rain is limited as compared to that of Ku-band scatterometers, ASCAT winds can be used as reference for tuning the Ku-band QC. Moreover, thanks to the inclined orbit of RapidScat, a large ...