Revisiting estimation of TC winds from IR Imagery

Making sense of the data Data and documentation Flight-level data ( ) Estimates of tangential wind at the 500km radius (GFS) IR images (3-hourly here) Best track (intensity, motion) Methods to estimate surface inflow angles Methods to reduce winds from flight-level to the surface Analyses Analyze aircraft data on a polar grid, motion relative – Apply surface reduction – Decompose into wavenumber 0, 1, and 2 Analyze IR images on a polar grid, motion relative – Decompose into 2-D principle components

Method Single-field principle component analysis (SFPCA; Bretherton et al. 1992) applied to the amplitude and phase of the wind field – This relates intensity, latitude, translation speed, and the IR principle components to the surface wind speeds Extrapolate the Amplitudes of wavenumbers through the 166km to 500km region of the vortex Apply inflow angles that are a function of translation speed, intensity, radius, and the radius of maximum wind (Zhang and Uhlhorn 2012)

Example Hurricane Ike 10 Sep UTC

3-hourly wind estimates Ike 2008