Changes in tropical cyclone-associated precipitation of highly damaging Philippine typhoons using high-resolution PGW simulations and multiple-experiment approach

Abstract. This study has investigated the changes in tropical cyclone (TC)-associated precipitation in the Philippines under past (pre-industrial) and future climate scenarios using the pseudo-global warming technique and dynamical downscaling. What is novel in this work is the use of high-resolution PGW simulations (3 km and 5 km) and a multiple-experiment approach to directly quantify TC precipitation changes over the Philippines, revealing the nonlinear response of precipitation scaling to different warming pathways. Future climate simulations project a significant increase in TC precipitation, consistent with Clausius-Clapeyron (CC) scaling expectations. However, small deviations from this expected scaling are noted, attributed to factors such as increased TC intensity and atmospheric warming. The simulated TC precipitation in the past climate is found to be lower than that in the current climate. Our convection-permitting model experiments estimate that the average TC inner-core precipitation rate changes from past to current climate conditions are 6 % and 8 % for the 5 km and 3 km, respectively. Under the SSP5-8.5 future scenario, simulations indicate a robust rise (by approximately 6 % per 1 K increase in SST relative to the current climate) in the mean precipitation rates for intense TCs such as Haiyan (2013), Bopha (2012), and Mangkhut (2018) in both the 5 km and 3 km experiments. Notably, simulations that warm only land and sea surfaces show increases exceeding CC expectations, reaching up to 13 % per 1 K increase in SST. Increases in both radial and vertical extent of rain are observed. Our analysis shows that these changes are linked to enhanced latent heating, moisture, and updrafts in the TCs’ inner-core regions, emphasizing intricate interactions between atmospheric processes and the evolving structure of TCs. Our study underscores that variations in TC intensity and structure play a crucial role in influencing the scaling relationship between sea surface temperatures and TC-associated precipitation in the Philippines.