Title :
A systematic comparison of QuikSCAT and SAR ocean surface wind speeds
Author :
Monaldo, Frank M. ; Thompson, Donald R. ; Pichel, William G. ; Clemente-Colón, Pablo
Author_Institution :
Ocean Remote Sensing Group, Johns Hopkins Univ., Laurel, MD, USA
Abstract :
We performed a systematic comparison of wind speed measurements from the SeaWinds QuikSCAT scatterometer and wind speeds computed from RADARSAT-1 synthetic aperture radar (SAR) normalized radar cross section measurements. These comparisons were made over in the Gulf of Alaska and extended over a two-year period, 2000 and 2001. The SAR wind speed estimates require a wind direction to initialize the retrieval. Here, we first used wind directions from the Navy Operational Global Atmospheric Prediction System (NOGAPS) model. For these retrievals, the standard deviation between the resulting SAR and QuikSCAT wind speed measurements was 1.78 m/s. When we used the QuikSCAT-measured wind directions to initialize the inversion, comparisons improve to a standard deviation of 1.36 m/s. We used these SAR-scatterometer comparisons to generate a new C-band horizontal polarization model function. With this new model function, the wind speed inversion improves to a standard deviation of 1.24 m/s with no mean bias. These results strongly suggest that SAR and QuikSCAT measurements can be combined to make better high-resolution wind measurements than either instrument could alone in coastal areas.
Keywords :
atmospheric boundary layer; atmospheric techniques; backscatter; oceanographic regions; radar cross-sections; remote sensing by radar; spaceborne radar; synthetic aperture radar; wind; AD 2000; AD 2001; C-band horizontal polarization model function; Gulf of Alaska; NOGAPS model; Navy Operational Global Atmospheric Prediction System; QuikSCAT scatterometer; RADARS AT-1; SAR; SAR-scatterometer; Sea Winds; coastal areas; high-resolution measurements; marine boundary layer; mean bias; ocean surface wind speeds; radar cross section measurements; standard deviation; synthetic aperture radar; wind direction; wind speed inversion; wind speed measurements; Area measurement; Atmospheric measurements; Oceans; Performance evaluation; Radar measurements; Sea measurements; Sea surface; Synthetic aperture radar; Velocity measurement; Wind speed;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2003.817213