Regional Climate Downscaling under CORDEX Southeast Asia and the Southeast Asia Regional Climate Change Information System (SARCCIS)

This Workshop will be co-organized by the Ramkhamhaeng University Center of Regional Climate Change and Renewable Energy (RU-CORE) and the Center for Earth Sciences and Environment, the National University of Malaysia. It provides an overview of the regional climate downscaling conducted in the Southeast Asia (SEA) under the CORDEX Southeast Asia and its key findings. It also introduces the CORDEX Southeast Asia data portal, coined as the Southeast Asia Regional Climate Change Information System (SARCCIS) (http://www.rucore.ru.ac.th/SARCCIS). Information on what kind of data, its format and how to access the portal will be discussed. A total of 12 General Circulation Models (GCMs) have been downscaled using 7 Regional Climate Models (RCMs) to a resolution of 25 km x 25 km over the SEA domain (85.5o E – 146.5o E, 15o S – 27o N) for two different Representative Concentration Pathways (RCP) scenarios, RCP4.5 and RCP8.5.

The GCMs were selected on the basis of their performances in simulating the regional monsoon circulation and inter-annual variability in the SEA Region. The ensemble members were selected based on their performances in simulating the observed climatology for the historical period of 1976 – 2005. Based on 14 members, a simple equal-weighted ensemble was constructed to evaluate the SEA mean precipitation changes. The ensemble mean shows appropriate reproduction of the SEA mean spatial precipitation pattern with systematic wet biases, which originated largely from RegCM4 simulations.

For future changes of the 21st century, we consider early century (2011-2040), mid-century (2041-2070) and late century (2071-2100). Wetter conditions are projected throughout the century over Indochina and eastern Philippines during December-January- February (DJF) while over the Maritime Continent a drying tendency prevails. Over Myanmar, northern Thailand and Laos, rainfall increases as much as 20% are projected, while 5-10% increases are projected over northern Vietnam and eastern Philippines. For June-July- August (JJA), the projected condition is predominantly drier, particularly over the Indonesian region with rainfall decreases up to 20% in most regions (> 20% in Java).

In Myanmar rainfall increases up to 10% are projected, making it a region with projected increase of rainfall in both seasons. Examination of responses of individual members shows prominent inter-model variations, reflecting uncertainty in the projection that must be taken into account. Generally, the projected drier and wetter conditions coincide with areas of enhanced subsidence (divergence) and rising motion (convergence). The presentation continues on explaining the data available in SARCCIS, their format, how to access and process will be discussed.

Date: 03rd October 2019

Time: 4:30 PM. – 7:00 PM

Resource People

Asst. Prof. Dr. Jerasorn Santisirisomboon

Ramkamhaeng University
Center of Regional Climate Change and Renewable Energy
(RU-CORE)
Thailand

Dr. Kamphol Promjirapawat

Ramkamhaeng University
Center of Regional Climate Change and Renewable Energy
(RU-CORE)
Thailand

Mr. Ratchanan Srisawadwong

Ramkamhaeng University
Center of Regional Climate Change and Renewable Energy
(RU-CORE)
Thailand

Dr. Fredolin Tangang

Universiti Kebangsaan Malaysia
Malaysia