Characterization of the Tropical Cyclones Wind Radii in the North Western Pacific Basin Using the ASCAT Winds Data Products

Abstract

We investigate the characteristic of the wind radii of the Tropical Cyclone (TC) in the North Western Pacific basin using the winds data product derived from the Advanced Scatterometer (ASCAT) launched on board the Metop-A satellite. The ASCAT Level 2 winds climate data record produced by the Royal Netherlands Meteorological Institute (KNMI) and obtained through the EUMETSAT Data Centre covering the tropical cyclones between the year of 2007 and 2012 are being investigated in this study. Each of the ASCAT orbits will be spatially and temporally collocated within 500-km radius and 30-minute time window, respectively, with the tropical cyclone best track data in the North Western Pacific basin obtained from the Joint Typhoon Warning Center. Then the standard wind radii of 34-knot, 50-knot and 64-knot will be evaluated and a comparison with the wind radii reported from the best track will be made. We present a novel wind speed radii characterization technique by computing the normalized wind radii of the storm scenes matchup and then compute a composite of the distribution of the entire North Western Pacific basin. Wind speeds from ASCAT were quality controlled using an appropriate quality flag provided in the data. A statistical ASCAT wind radii performance with respect to the best track will be presented.