Скачать или смотреть SoMAS / ITPA - WRF-SBM Simulation for the Two Distinct Modes in a One-day Rainfall Event

Takamichi Iguchi from the NASA Goddard Space Flight Center in Greenbelt, MD speaks to SoMAS on Wednesday October 30, 2013.

Topic: "WRF-SBM Simulation for the Two Distinct Modes in a One-day Rainfall Event During Midlatitude Continental Convective Clouds Experiment"

ABSTRACT:
Microphysical structure of precipitation at the ground is of interest in developing cloud microphysical models, in terms of improving forecast accuracy of the surface precipitation rate as well as validating the cloud microphysics. Unlike widely-used bulk cloud microphysics, spectral bin microphysics (SBM) allows prediction of hydrometeor particle size distributions and subsequently explicit representation of the precipitation microphysical structure. Analysis and verification of the ground precipitation microphysics can be a new application of the simulation to show possibilities of the up-to-date models.

This study reports on the analysis of distinct rainfall microphysical structures observed by the surface laser optical Particle Size and Velocity (Parsivel) disdrometers for the one-day rainfall event in central Oklahoma. According to the systematic differences in rainfall rate and bulk effective droplet radius, the sampling data can be divided into two groups; the rainfall mostly from the deep convective clouds has relatively high rainfall rate and large bulk effective droplet radius, whereas the reverse is true for the rainfall from the shallow warm clouds. The Weather Research and Forecasting model coupled with spectral bin microphysics (WRF-SBM) successfully reproduces the two distinct modes in the observed rainfall microphysical structure. The simulation result demonstrates how the cloud physics and the weather condition on the day are involved in forming the unique surface rainfall characteristic.