Observations of the structure and evolution of surface and flight-level wind asymmetries in Hurricane Rita (2005)

The Stepped Frequency Microwave Radiometer (SFMR) has received attention for its ability to measure surface wind asymmetries. Concurrent measurements of aircraft flight-level and SFMR surface winds are used here to document the wind field evolution over three days in Hurricane Rita (2005). The magnitude and azimuthal location (phase) of the peak asymmetry varied at both levels over time. The asymmetry phase was aligned to the right of storm track on the first day. By the third day, the phase remained to the right of storm track, but there was a 45-degree shift between the surface and flight-level, resulting in azimuthal variations in the ratio of surface to flight-level winds. The differences between the surface and flight-level maximum wind radii also varied, indicating a vortex whose tilt was increasing. The asymmetry magnitude and phase evolution are not fully explained by previous studies, suggesting that other processes are occurring in the storm.