Level One Validation Concept for GPM over Dallas - Fort Worth Urban Network

Abstract:

The Global Precipitation Measurement (GPM) Core Observatory was launched on February 27, 2014. The two advanced instruments onboard GPM, namely, Dual-frequency Precipitation Radar (DPR) and GPM Microwave Imager (GMI), can provide measurement of rainfall, snowfall, ice and other precipitation over most of the globe. As an integral part of all satellite precipitation missions, ground validation helps to quantify precipitation measurement uncertainty and provide insight into the physical and statistical basis of retrieval algorithms. Among various validation instruments, ground-based dual-polarization radar (at S, C and X band frequencies) has been shown to be a powerful tool to estimate surface rainfall.

This paper will present the concept of level one validation of GPM using high resolution precipitation observations from DFW network. The area of interest in this study is Dallas-Fort Worth (DFW) Metroplex, which hosts a network of six high-resolution dual-polarization X-band radars operated by the center for Collaborative Adaptive Sensing of the Atmosphere (CASA) and the NWS WSR-88DP radar (i.e., KFWS radar). The DFW network QPE product has been shown to be of excellent quality, in terms of accuracy as well as space time resolution (Chen and Chandrasekar, Journal of Hydrology, May (2015)). Detailed comparisons will be conducted between GPM based rainfall estimates and ground radar observations collected during the GPM satellite overpasses over DFW region. Dual-polarization based raindrop size distribution (DSD) retrieval, quantitative precipitation estimation (QPE), and hydrometeor classifications will be presented in detail.