A Rain Drop Size Distribution (DSD) Retrieval Algorithm for CASA DFW Urban Radar Network

The raindrop size distribution (DSD) is a fundamental descriptor of rain microphysics, and hence extensive effort has been under way to measure DSD through both in-situ sampling devices as well as remote observations. The raindrop size distribution along with shape information, essentially determines the behavior of dual polarization observations of precipitation. A remote estimator of DSD from radar observation significantly enhances the area over which DSD is observed.

There are several DSD estimators available from single radar observations (Bringi and Chandrasekar 2001, Gorgucci et al. 2002). More recently Yoshikawa et al. (2012) developed a DSD estimate for X-band dual-polarization radar that uses a maximum likelihood estimator to retrieve the optimal DSD parameters. This 3-step procedure, shows good performance when tested on simulated data.

The Dallas-Fort Worth urban demonstration radar network is being implemented by the Center for Collaborative Adaptive Sensing of Atmosphere (CASA), as a demonstration of the X-band radar network concept in a metropolitan region. Though it is an operational radar network, it provides great opportunity to study the DSD variability over different types of storms for scientific applications. This paper presents implementation and evaluation of various RSD estimation techniques in the DFW Urban Demonstration Testbed.