Examining the application of CMIP6 General Circulation Models in regional flood projections for the Mekong River Delta, Viet Nam

In the 21st century, the Mekong River Delta (MRD), in Viet Nam, is projected to experience intensified extreme precipitation events due to global warming. General Circulation Models (GCMs) offer possible future climate estimations globally that adeptly capture large-scale features of precipitation extremes under different scenario settings. However, challenges persist in replicating detailed regional flood patterns within the MRD. This study focuses on the application of CMIP6 models, including European Centre for Medium-Range Weather Forecasts Reanalysis v5—ERA5, Situ-Based Data Set of Temperature and Precipitation Extremes—HadEX3, and Rainfall Estimates on a Gridded Network—REGEN. Before it can be applied for the future flood assessment for the study area, this study compared annual maximum daily precipitation, derived from CMIP6, Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), and ground-based precipitation records, from 1978 to 2012, and identified the relationships between annual maximum daily precipitation and flooded area. Accordingly, this study projects precipitation and flooded areas for the near future (2026–2050), mid-future (2050–2075), and far future (2075-2100). The preliminary results will be presented in this meeting. In light of the persistent global warming trend, the expected rise in flooding within the MRD and variations in heavy precipitation patterns emphasize the importance of the findings in this study. These results play a crucial role in mitigating adverse effects and fortifying resilience to global warming and climate change in the MRD.

KEY WORDS: CMIP6, CHIRPS, flood, extreme precipitation, global warming.