Summer Convective Afternoon Rainfall Simulation and Projection Using WRF Driven by Global Climate Model. Part II: Over South China and Luzon

Abstract

This study is the second of a two-part investigation into summer convective afternoon rainfall (CAR) simulation and projection over the East Asian continents. In Part I, we examined the CAR activity over Taiwan. In this study we focus on CAR activity over South China and Luzon using the WRF (Weather Research and Forecasting Model) driven by HiRAM (High Resolution Atmospheric Model) (i.e., WRF-HiRAM). These examinations focus on two time-sliced simulations assuming the climate conditions at present (1979 -2003, historical run) and at the end of the 21 st century (2075 -2099, RCP 8.5 scenario). The results show that WRF-HiRAM is capable of simulating the spatial-temporal variation in CAR activity over South China and Luzon close to the recorded observations. In the future projections, WRF-HiRAM predicts that CAR events over most of South China and eastern Luzon will become fewer but stronger. Conversely, CAR events over western Luzon will become more frequent and stronger. Analyses also indicate that the projected change in CAR amount over most of South China (except for the coastal regions) and Luzon will be dominated by the change in CAR rate, not the change in CAR frequency. As for the cause of change in CAR rate, WRF-HiRAM projects that atmospheric humidity over South China and Luzon will increase significantly in the future. This will lead to an increase in local CAR rate. In contrast, the projected change in CAR frequency over South China and Luzon is suggested to be greatly modulated by the change in daytime surface wind convergence and thermal instability. Examinations were also performed to document the characteristics and causes of the projected change in CAR activity extracted from HiRAM.

The Taiwan Climate Change Projection Information and Adaptation Knowledge Platform: A Decade of Climate Research

“…The time period between 1960-2005 was used as a historical baseline, and data between 2006-2100 underwent statistical downscaling, which was carried using spatial interpolation and bias correction using the ECDF methods utilized in the previous project phase. For dynamical downscaling, in addition to the MRI model, a high-resolution atmospheric model (HiRAM C384) [21][22][23][24][25][26][27][28][29][30][31] developed by the Geophysical Fluid Dynamics Laboratory (GFDL) was also used for cross-comparison, with a resolution of 25 km, baseline period of 1979-2003, simulating projections during 2039-2065 and 2075-2099 using the RCP8.5 scenario. These models were coupled with WRF to assess the impact of extreme and typhoon events in the context of topics such as flooding and landslides.…”

Advantages of GSMaP Data for Multi‐Timescale Precipitation Estimation in Luzon

“…In contrast, satellite‐based rainfall estimation (SRE) with high spatial coverage can monitor a wider spatial range of rainfall variations (Da Silva et al., 2021; Huang et al., 2023). Therefore, SRE is often used for various research purposes (e.g., climate studies, validating model performance, and other studies) (Huang et al., 2016; Huang, Liu, Hsu, et al., 2021; Huang, Hsu, et al., 2022; Koralegedara et al., 2023).…”