Extended Abstract (176K)13A.1
Analysis of QuikScat rain-flagged winds within the tropical cyclone environment
Deborah K. Smith, Remote Sensing Systems, Santa Rosa, CA; and F. J. Wentz and C. A. Mears
Quality wind vectors are derived from the SeaWinds instrument onboard QuikScat within typical conditions, that of winds below 15 m/s and no rain. It is more difficult to retrieve quality winds within the high wind, intense rain conditions of a tropical cyclone. The scattering and attenuation effects of rain cause altered wind speeds and erroneous directions most often aligned perpendicular to the satellite sub-track. These poor quality winds often obscure the center of the cyclonic flow. Knowing accurately which QuikScat winds are believable and extracting out enough information to forecast intensity, determine a storm center and measure accurate wind radii is a top priority for forecasters. In this presentation, we use examples from over 2200 tropical cyclone overpasses located in our QuikScat tropical cyclone data archive (available at http://www.ssmi.com/hurricane/archived_storms.html). We address the questions many forecasters have expressed, including 1) how high of a wind speed can be retrieved and with what uncertainty? 2) how accurate is the autonomous scatterometer rain flag used in our data set? and 3) how valid are the QuikScat wind speeds retrieved in the rain-flagged data? The answer to this last question may increase the forecaster's ability to maximize the information drawn from what may initially look like useless wind data.
Session 13A, Tropical Cyclone Observations and Structure II(Parallel with Sessions 13B, 13C, and 13D)
Thursday, 2 May 2002, 11:00 AM-12:30 PM
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