4.2 Polarimetric Thermodynamic Retrievals in Convective and Stratiform Regions: Results from Spectral Bin Models

Tuesday, 23 October 2018: 9:15 AM
Pinnacle room (Stoweflake Mountain Resort )
Jacob Carlin, CIMMS/Univ. of Oklahoma, Norman, OK; and A. Ryzhkov

Obtaining information about latent heating and cooling rates due to hydrometeor phase changes within precipitation systems remains a challenge for both the observational and modeling meteorological communities. Due to a lack of in situ observations, a number of methods have been proposed for retrieving heating and cooling rates from remote sensing data. More specifically, approaches utilizing radar data have generally been limited to velocity and reflectivity. Owing to distinct signatures associated with diabatic microphysical processes, dual-polarization radar data have the potential to provide enhanced insight into microphysical heating and cooling rates within precipitation systems.

In this work, a suite of microphysical spectral bin models coupled to a polarimetric radar operator are developed and used to relate polarimetric signatures to heating and cooling rates in both stratiform and convective precipitation. In the melting layer, preliminary results suggest that the maximum Z and ZDR in the brightband contain little information about the maximum cooling rate, while the maximum KDP is highly correlated with the maximum cooling rate. In the convective region, ZDR column height is shown to be closely related to the latent heating rate within the updraft. Similarly, KDP within convective downdrafts appears to hold potential for constraining estimates of cooling due to melting hail and graupel. These early results suggest a potential new use for polarimetric radar data to inform numerical weather prediction models.

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