Wednesday, 12 February 2003
Improved quality control for QuikSCAT near real-time data
SeaWinds on QuikSCAT, launched in June 1999, provides a new source of surface wind information over the world's oceans. This new window on global surface vector winds has been a great aid to real-time operational users, especially in remote areas of the world. As with in situ observations, the quality of remotely-sensed geophysical data is closely tied to the characteristics of the instrument. But remotely-sensed scatterometer winds also have a whole range of additional quality control concerns different from those of in situ observation systems. The retrieval of geophysical information from the raw satellite measurements introduces uncertainties but also produces diagnostics about the reliability of the retrieved quantities. A working knowledge of the limitations of the instrument and its wind retrieval algorithms will improve the use of the near real-time QuikSCAT winds.
A characteristic swath of QuikSCAT data in the Western Atlantic illustrates typical benefits and deficiencies of these valuable data. The effects of the instrument's design and wind retrieval algorithm on the quality of the data under normal and extraordinary circumstances are presented. The effects of high and low winds, heavy rain, and aspects of the instrument's measurement geometry will be illustrated by selected cases from the swath.