Ground Validation of GPM DPR Algorithms by Hydrometeor Measurement and Polarimetric Radar Observations of Winter Snow Clouds in the Case of 4 February 2018
Abstract
The Global Precipitation Measurement (GPM) core observatory carries dual-frequency precipitation radar (DPR). The GPM DPR provides some products associated with the microphysical structures of precipitating clouds. The "typePrecip" indicates the classification of precipitation types into stratiform, convective and other. The "flagHeavyIcePrecip" is a flag for detecting intense ice precipitation above the -10ºC height and determining as convective precipitation in winter.
The GPM DPR precipitation type classification algorithm needs to be validated using ground level data for winter snow clouds because bright band (melting layer) cannot be detected. Suzuki et al. (2019) conducted hydrometeor measurements of winter snowfall for the ground validation of precipitation type classification focusing on the precipitation particles observed by the Ground-based Particle Image and Mass Measurement System (G-PIMMS; Suzuki et al. 2016). The G-PIMMS observations showed that the major precipitation particle type (graupel or snow) was different in the precipitation types (convective or stratiform) classified by GPM DPR algorithm. However, it was a qualitatively comparison between a pixel data by DPR and a certain spot data by G-PIMMS (point-to-point comparison). So, a two-dimensional evaluations are necessary for the quantitative ground validation of the GPM DPR algorithms. In this study, for the further enhancement of validation accuracy, we conducted two-dimensional quantitative comparison between the GPM DPR and the X-band polarimetric radar (XRAIN), focusing on hydrometeor information from G-PIMMS as reference. At 06:24 JST on 4 February 2018, the GPM DPR passed over two G-PIMMS observation sites along the coast of the Japan Sea, and classified as different precipitation types. The two-dimensional HC distribution of the XRAIN showed that graupel was generally dominant at the pixels where the DPR classified into convective. In addition, as a result of validation of the "flagHeavyIcePrecip" on the CAPPI of -10ºC height, the "flagHeavyIcePrecip" was detected at the pixels that dominant hydrometeor was graupel.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A53L3079K
- Keywords:
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- 3354 Precipitation;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 1840 Hydrometeorology;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY