|Algorithm development PI: Dr. Akira Shibata|
(JAXA Earth Observation Research and application Center)
This document briefly describes some caveats for the AMSR Level 2 standard products of sea surface wind speed.
Values of sea surface wind speed are retrieved over global oceans (except over sea ice) in this product. However, missing values are set to the areas of precipitation (more than about 1mm/h), coastal regions (within about few score kilometers from coastlines), and sun-glitter (less than 10 degrees of relative angle made between the Sun and observing directions). Since the accuracy in correcting wind direction effect using 6.925-GHz horizontal polarization channel degrades near the sun-glitter areas with the relative angle between 10 and 25 degrees, retrieval error of sea surface wind speed may increase. By the same reason, wind speed errors may increase in the coastal regions (distance from coastlines is between few score kilometers and 100km). All possible sea ice areas are excluded. Reason of missing is included in the quality flag information of the product.
Range of sea surface wind speed retrieval is between 0 and 30 m/s. Retrieval error was evaluated within about 1.1m/s (rms) by comparing to mooring buoy wind speeds obtained through the Global Telecommunication System (GTS) and Internet (e.g., TAO buoys). The comparison was made using the data of April and July 2003.