A QuikSCAT climatology of tropical cyclone size
Abstract
QuikSCAT data of nearsurface wind vectors for the years 19992008 are used to create a climatology of tropical cyclone (TC) size, defined as the radius of vanishing winds. The azimuthallyaveraged radius of 12 ms^{1} wind (r_{12}) is calculated for a subset of TCs (N = 2154) whose centers of circulation were clearly identifiable via subjective analysis of the QuikSCATanalyzed wind field. The outer radius, r_{0}, is determined from r_{12} using an outer wind structure model that assumes no deep convection beyond r_{12}. The global median values of r_{12} and r_{0} are 197 km and 423 km, respectively, with statistically significant variation across ocean basins. The global distribution of r_{12} is found to be approximately lognormal, the distribution of r_{0} is quantitatively much closer to lognormal, and the improvement in fit between r_{12} and r_{0} is attributed to the combined effect of the nature of the model employed and the paired distributions of r_{12} and f. Moreover, the normalization employed by Dean et al. (2009) is found to weaken rather than improve the lognormal fit. Finally, within a given storm, both r_{12} and r_{0} tend to expand very slowly with time early in the storm lifecycle and then becomes quasiconstant, though significant variance exists across storms.
 Publication:

Geophysical Research Letters
 Pub Date:
 September 2010
 DOI:
 10.1029/2010GL044558
 Bibcode:
 2010GeoRL..3718816C
 Keywords:

 Atmospheric Processes: Tropical meteorology;
 Atmospheric Processes: Mesoscale meteorology;
 Atmospheric Processes: Climatology (1616;
 1620;
 3305;
 4215;
 8408);
 Nonlinear Geophysics: Probability distributions;
 heavy and fattailed (3265);
 Atmospheric Processes: Theoretical modeling