Evaluation Of Storm-Resolving Models In Simulating Precipitation Efficiency Over The Asian Monsoon Region
Presenter: Thabo Elias Makgoale P131
Co-Author(s): Sylvia Sullivan
Advisor(s): Dr. Sylvia Sullivan
1Hydrology & Atmospheric Sciences
Cloud microphysics plays an important role in modulating precipitation efficiency εp, the percentage of atmospheric condensate that reaches the surface as precipitation. Precipitation intensity can be scaled as the product of this efficiency and an integrated condensation rate. With the availability of storm-resolving models (SRMs), atmospheric ascent rates and hence integrated condensation rates are more reliably simulated, meaning that constraint of precipitation efficiencies is becoming increasingly important. Precipitation efficiency has been quantified at coarse resolutions from the CMIP6 and RCEMIP ensembles, but not yet from full-complexity SRMs. In this study, output of the Dynamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains (DYAMOND) initiative is used to study characteristics of εp We calculate εp over a South Asian domain during the monsoon with the DYAMOND Summer data, using the ratio of surface precipitation intensity to column-integrated cloud water content (Li et al. 2022). For one of the models, εp is additionally calculated as the ratio of surface precipitation to the integrated condensation rate. The outcomes of this analysis reveal qualitatively different spatial patterns of precipitation efficiency between different SRMS over the Asian Monsoon Region with GEOS-5 exhibiting the highest efficiency on average and NICAM exhibiting the lowest. Additionally, a shift toward higher precipitation efficiency occurs in most models for extreme events. All models indicate elevated precipitation efficiency in mountainous regions where topography significantly contributes to the forced ascent of moist air, resulting in orographic precipitation. Furthermore, the models exhibit strong land-sea contrast in their efficiency distribution. The models show diurnal cycles in precipitation efficiency of varying magnitude.