Characterization of Passive Microwave Retrieval Uncertainty over Complex Terrain
Abstract
Difficulties in representation of high rainfall variability over mountainous areas using ground based sensors make satellite precipitation datasets attractive for hydrologic studies over these regions. The GPM constellation includes several satellites with passive microwave sensors (PMW) onboard, which are used to retrieve surface precipitation. However, PMW precipitation estimation is highly variable over complex topography due to orographic enhancement effects on precipitation structure and variability. Evaluating the terrain and orographic precipitation enhancement effects on the GPROF algorithm could give us insights to address retrieval error issues associated with precipitation detection, vertical structure and microphysics. The following issues have been identified for PMW retrieval algorithms and motivate our current research: variability of the precipitation inside the sampling volumes (Non-Uniform Beam Filling effects - NUBF), geometric effects (parallax), physical properties of hydrometeors and surface conditions. This study is facilitated by data collected during the Olympic Peninsula NASA field experiment (NASA OLYMPEX). The aim of this study is to understand the source of algorithm uncertainties, which are caused by physiographic and meteorological regimes. Residual errors represent the algorithm's inability to separate conditions that have similar signatures but different rain or snow intensities. To achieve the study aim, we will analyze the assigned profile weights and in particularly whether GPROF is choosing precipitation profiles correctly. The study conducts an independent error analysis to understand radiometer's capabilities to capture the precipitation structure and how that signature is related to the surface rainfall in the OLYMPEX complex terrain environment. Specifically, we will evaluate the relationship between ice aloft and surface rainfall rate derived by a locally-deployed X-band Dual Polarization weather radar (Doppler on Wheals, DOW, radar). Finally, we will assess the significance of the parallax issue over this complex terrain area.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H53C..03D
- Keywords:
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- 3354 Precipitation;
- ATMOSPHERIC PROCESSESDE: 3360 Remote sensing;
- ATMOSPHERIC PROCESSESDE: 1817 Extreme events;
- HYDROLOGYDE: 1847 Modeling;
- HYDROLOGY