Stability in SeaWinds Quality Control

Until now, the KNMI Quality Control (QC) in the SeaWinds wind processing was based on the value of the Maximum Likelihood Estimator (MLE) in the input product from NOAA. Since this input product will change in the near future, especially with regards to the formulation of the MLE, it is necessary to make the QC in the OSI SAF wind products independent of the MLEs as computed by NOAA.

This report describes how the QC procedure is modified and made independent of the NOAA MLE with the aim to provide continuity in the KNMI SeaWinds wind product quality. The results of two new QC algorithms are compared with those of the old QC and it is shown that the best new QC algorithm performs even slightly better than the old one.

The JPL rain flag in the NOAA product is also used in the KNMI QC. The rain flagging will also change and part of this report is devoted to the evaluation and possible reduction of its impact on the OSI SAF wind processing.