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Public Release of QuikSCAT Level 2B Ocean Wind Vectors in 12.5km Slice Composites Version 4.0

Thursday, April 5, 2018

The PO.DAAC is pleased to announce the public release of the “QuikSCAT Level 2B Ocean Wind Vectors in 12.5km Slice Composites Version 4.0” (hereafter L2B Version 4.0) dataset. This dataset consists of Version 4.0 Level 2B (L2B) science-quality ocean surface wind vector retrievals from the Quick Scatterometer (QuikSCAT). L2B data are in an along-track/cross-track swath grid with a pixel (wind vector cell) resolution of 12.5 km. This resolution is achieved through a slice composite technique in which high-resolution slice measurements from L1B data are composited into a 12.5 km wind vector cell. The data time series begins on 27 October 1999 and ends on 22 November 2009.

Version 4.0 processing begins with the same L1B (time-ordered backscatter) data as used in the previous Version 3.1 processing. Version 4.0 improves upon the previous Version 3.1 processing by fundamentally adjusting the baseline geophysical model function (GMF) using a sea-surface temperature (SST) dependent GMF developed by Lucrezia Ricciardulli (Remote Sensing Systems) which fixes persistent wind speed retrieval biases over colder ocean surface conditions. Version 4.0 improves upon the legacy enhanced coastal processing using a Land Contamination Ratio (LCR) method which is augmented using an Expected Sigma-0 (LCRES) technique that retrieves winds even closer to the coast compared to Version 3.1. The last improvement is with regard to quality flagging, in which the entire flagging schema is simplified, and additional quality flags are provided in both the “flags” and “eflags” variables to enable users with even more quality filtering capability.

Each L2B file corresponds to a specific orbital revolution (rev) number, which begins at the southernmost point of the ascending orbit. This is the official dataset produced by the QuikSCAT Project through the SeaWinds Processing and Analysis Center (SeaPAC). More details on the processing changes and improvements will be published in the near future, including an updated Level 2B user guide which is now undergoing final review for release.

More information, documentation, read software and access to the dataset may be gained through the PO.DAAC Web Portal by clicking here:

Users who have any further questions or concerns are encouraged to visit our Forum site: