Retrieval of hurricane turbulence parameters using airborne Doppler radar measurements

An accurate estimate of hurricane turbulence is crucial to better understand the role of turbulent processes in the energy transport within the storm in general and in the hurricane boundary layer (HBL), in particular. A better characterization of hurricane turbulence, especially in high wind regimes where observational data are lacking, could provide tremendous insights on the mechanisms involved in hurricane intensity change. Estimation of turbulent energy in a hurricane has usually been conducted using point measurements, which does not allow for a global assessment of the distribution of the turbulence throughout the storm. Moreover, acquisition of in-situ measurements in the lowest parts of the HBL has been quite limited as it has proved to be dangerous. Because Doppler radars generally provide data over a large spatial coverage without requiring excessive danger, the use of airborne Doppler measurements offers a unique opportunity to estimate the distribution of turbulence throughout a hurricane and the possibility to retrieve various turbulence parameters. The present study will describe a method of estimation of turbulent kinetic energy (TKE) in a hurricane using NOAA tail Doppler radar data. Moreover, the measured spectral width data will be used to estimate dissipation in the HBL. Mapping of the TKE and dissipation distribution will be provided along with comparisons with in-situ measurements to assess the quality of the retrievals.