Extended Abstract (160K)P1.26
Operational use of QuikSCAT over tropical cyclones
Roger T. Edson, Anteon Corporation, Univ. of Guam, Mangiliao, Guam; and M. A. Lander, C. E. Cantrell, J. L. Franklin, P. S. Chang, and J. D. Hawkins
QuikSCAT data over all global tropical cyclones are examined during the past 3 1/2 years in conjunction with the development of a user's guide for the tropical cyclone forecast centers. The QuikSCAT scatterometer's unique ability to provide both wind speed and direction on a nearly bi-daily basis has significantly increased the forecaster's near real-time knowledge of tropical cyclone genesis, intensification potential, outer wind structure, and a 'minimum estimate' for a tropical cyclone's maximum sustained winds. However, in many cases the data could not be directly analyzed without using various interpretation procedures. Wind speeds were found to be extremely accurate, especially for the radius of gale force winds. However, in rain-contaminated areas, light winds were often greatly overestimated; while in heavy winds, wind speeds were reasonable up to a working range of 30 to 40 m/s. Higher than this, the winds were generally underestimated. The greatest interpretation issue focused on the correct wind direction selection procedure. Rain-flagged wind vector cells greatly affected these results. The various available automated ambiguity selection algorithms often had difficulties resolving a circulation center when large areas of the tropical cyclone's center were flagged or when the center was not accurately positioned in the NWP analysis fields for the ambiguity nudging. This presentation presents a methodology to accurately determine a center position and make a judgment on the proper representation of the surrounding wind field. Quantitative results and comparisons to operational best tracks are shown.
Poster Session 1, Tropical Cyclones, Large-scale Dynamics and Convection
Monday, 29 April 2002, 11:00 AM-12:30 PM
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