Abstract
QuikSCAT data of near-surface wind vectors for the years 1999–2008 are used to create a climatology of tropical cyclone (TC) size, defined as the radius of vanishing winds. The azimuthally-averaged radius of 12 ms−1 [ms superscript -1] wind (r12) [r subscript 12] is calculated for a subset of TCs (N = 2154) whose centers of circulation were clearly identifiable via subjective analysis of the QuikSCAT-analyzed wind field. The outer radius, r0 [r subscript 0], is determined from r12 [r subscript 12] using an outer wind structure model that assumes no deep convection beyond r12 [r subscript 12]. The global median values of r12 [r subscript 12] and r0 {r subscript 0] are 197 km and 423 km, respectively, with statistically significant variation across ocean basins. The global distribution of r12 [r subscript 12] is found to be approximately log-normal, the distribution of r0 [r subscript 0] is quantitatively much closer to log-normal, and the improvement in fit between r12 [r subscript 12] and r0 [r subscript 0] is attributed to the combined effect of the nature of the model employed and the paired distributions of r12 [r subscript 12] and f. Moreover, the normalization employed by Dean et al. (2009) is found to weaken rather than improve the log-normal fit. Finally, within a given storm, both r12 [r subscript 12] and r0 [r subscript 0]tend to expand very slowly with time early in the storm lifecycle and then becomes quasi-constant, though significant variance exists across storms.
Journal
Geophysical Research Letters
Publisher
American Geophysical Union
Citation
Chavas, D. R., and K. A. Emanuel. “A QuikSCAT climatology of tropical cyclone size.” Geophysical Research Letters 37.18 (2010) : n. pag. Copyright 2010 by the American Geophysical Union
Version:
Final published version