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Effects of Cloud Liquid‐Phase Microphysical Processes in Mixed‐Phase Cumuli Over the Tibetan Plateau
Author(s) -
Xu Xiaoqi,
Lu Chunsong,
Liu Yangang,
Gao Wenhua,
Wang Yuan,
Cheng Yueming,
Luo Shi,
Van Weverberg Kwinten
Publication year - 2020
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2020jd033371
Subject(s) - precipitation , weather research and forecasting model , environmental science , plateau (mathematics) , accretion (finance) , graupel , meteorology , entrainment (biomusicology) , atmospheric sciences , climatology , geology , physics , mathematics , mathematical analysis , astrophysics , rhythm , acoustics
Numerical simulations often overpredict precipitation over the Tibetan Plateau (TP). To examine the factors causing precipitation overprediction, different parameterizations of liquid‐phase microphysical processes (accretion, autoconversion, and entrainment mixing) are implemented into the Morrison microphysics scheme to simulate a TP precipitation event in summer with the Weather Research and Forecasting (WRF) model. The general spatial distribution and temporal trend of precipitation are captured by all simulations, but the precipitation rate is overpredicted. The results from sensitivity experiments suggest that compared to other examined liquid‐phase processes, the accretion process is more important in precipitation simulation over the TP region. Further investigation with the Heidke skill scores reveals that accretion parameterization that takes into account the raindrop size produces the most accurate results in terms of the total surface precipitation. This parameterization suppresses spurious accretion and does not produce liquid‐phase precipitation until cloud droplets are big enough. It is also confirmed that increasing the model resolution can reduce precipitation overprediction. Results from the case study are confirmed by the use of a 1‐month simulation.