Climate change modelling in Southeast Asia and Added values of regional climate downscaling

– Thanh Ngo-Duc, LOTUS LMI, University of Science and Technology of Hanoi (USTH, Vietnam –

Résumé :

Today, 8.6% of the world population is living in Southeast Asia (SEA). Any change in the climate system can have unequivocal impacts on the region’s socio-economic structures and living conditions. Given the high exposure and vulnerability of the region to extreme events, countries in SEA need to implement adaptation measures to lower their risk. Detailed information on future climate scenarios is thus needed. However, such information is still lacking in the region or generally based on global climate models (GCMs) that may have large uncertainties in a complex region such as SEA. In order to fill the gap, the Coordinated Regional Climate Downscaling EXperiment – Southeast Asia  (CORDEX-SEA) project was established and successfully gathered members from several countries to carry out a high-resolution multi-model regional climate downscaling experiment. Several statistical downscaling efforts have also been conducted.

In this presentation, an overview of climate change modeling activities in Southeast Asia and the recent findings of the CORDEX-SEA downscaling activities with the Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 6 (CMIP6) are first introduced. We address how the simulation of present-day extremes is influenced by the choices of various physical parameterizations to determine which schemes are well suited to simulate the climate over the region. Future projected mean climate and extreme conditions in SEA are subsequently analyzed. Lastly, we focus on a statistical downscaling approach for producing a high-resolution (10 km) climate dataset for Vietnam with the inputs from 35 CMIP6 GCMs. The new dataset is recommended for studies on climate change assessment and climate change impacts in Vietnam.