Downscaling of CMIP-5 GCMs for Future
Climate Projection over the Area of Southeast
Asia and Thailand
Jerasorn Santisirisomboon*, Fredolin Tangang, Ester Salimun,
Jingxiang Chung, Supari, Jaruthat Santisirisombon, Waranyu
Wongsaree, Kamphol Promjirapawat, Yod Sukamongkol, Prayat
Lewan, Ratchanan Srisawadwong, Patama Singhruck, Liew
Juneng, Faye Gruz, Gemma Narisma, Phan Van-Tan, Thanh
Ngo-Duc, Edvin Aldrian, Dodo Gunawan, Nikulin Grigory,
Hongwei Yang

Ramkhamhaeng University Center ofRegional Climate Change and Renewable
Energy (RU-CORE), Bangkok, Thailand

Related activities and projectes• Projected future changes of mean precipitation and its
variability over Thailand from multi-model regional
climate simulations of CORDEX Southeast Asia
• A Study of Watershed Management under Climate
Change: A Case Study at Sirindhorn International
Environmental Park
• A comparative study on the change of hydrologicalprocesses and fluxes in the Jiulong River and Chao
Phraya River basins under changing climate

Introduction• SEACLID/CORDEX Southeast Asia is acollaborative work involving many countries
from within and outside Southeast Asia region• A number of GCMs have been downscaledinto CORDEX SEA Domain of 25 km x 25 km
resolution.
• This presentation focuses on detailed analysis
of precipitation over Thailand for historicaland projection periods

List of Simulations Carried Out under
SEACLID/CORDEX SEA

Ensemble (of opportunity) Members considered
Considering only full RCP4.5, RCP8.5 simulation and removing
unrealistic simulations of current climate and simulations
deviate significantly (drifted) from the future projected byGCMs, the list provided the final ensemble members for thisstudy
1.
2.
3.
4.
5.
6.
7.

CNRM-CM5 (RegCM4)
CSIRO-Mk3-6-0 (RegCM4)
EC-EARTH (RegCM4)
MPI-ESM-MR (RegCM4)
CNRM-CM5 (RCA4)
HadGEM2-ES (RCA4)
HadGEM2-AO (WRF)

the ensemble was created using
equal weighting approach.

Meteorological stations in Thailand• There are 123 meteorologicalstations in Thailand• Based on the definition of Thai
Meteorological Department (TMD),
there are 5 regions in Thaiand.
12080
60
40
200
1951
1954
1957
1960
1963
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
2009

No. of Station100

Map of Thailand wth 9 sub-regions

CORDEX-SEA
25 km x 25 km
Domainx: location of stations
1-9: Sub-regions according
to TMD

Comparison between station data vsgridded products

RSME and correlation between station
averaged data vs gridded products
RMSECorrelation

GPCC appears slightly better. GPCC (50 km x 50 km),others (25 km x 25 km)

Comparison between GPCC and ensemble
for annual cycle during historical period

Ensemble tends to be wetter compared with GPCC

Taylor Diagram fordry monthEnsemble tends to be betterTaylor Diagram forwet monthEnsemble tends to be better

Historical period for dry months. More wet biases over the southern region

Historical period for dry months. More wet biases over the northern region

Fairly consistent between the two scenarios. During DEC wetter
condition is projected for all periods over northern region but dry
over southern. MAR and JAN are similar which tend to be drier
during end of century period. However for FEB drier condition
tends to be dominant

RCP4.5

Projection for dry month

RCP8.5

Faily consistent between the two scenarios.
Generally drier conditions is projected for wetmonths

Projection for wet monthComparison of coefficient of variation among GPCC, GCMs,and RCMs during dry and wet months• GPCC has high interannual
variabilities during drymonths buth in GCMs andRCMs were not wellsimulated.
• During wet months theinterannual variabilities isless but not well simulated
by GCMs and RCMs.

Summary• The ensemble simulations during historical period
were reasonable but tended to produce wet biases
over Thailand• For projection periods; tendency for wetter condition
during dry months and drier during wet months• The RCMs underestimated the interannual variability
during historical. This is due to the underestimationby the GCMs.

A Study of Watershed Management under Climate Change:
A Case Study at Sirindhorn International Environmental Park

• A research collaboration
NCAR and RU-CORE.
• Funded by the Natioanl
Research Council ofThailand.

A Study of Watershed Management under Climate Change:
A Case Study at Sirindhorn International Environmental Park
Dynamical downscaling
Regional Climate Model
DomainBaseline
Future projection
Grid resolution: RegCM4: CORDEX SEA: 1970 – 2005
: 2006 – 2040
: 25 km x 25 km

Statistical downscalig
Transfer function technique : ANNArea: Two river basins
Grid resolution: 5 km x 5 km
GCM
: MPI-ESM-MR
Scenario: RCP4.5 and RCP8.5
Water Evaluation and Planning model (WEAP)

Temperature
ProjectionPrecipitation
Projection

A comparative study on the change of hydrologicalprocesses and fluxes in the Jiulong River and Chao
Phraya River basins under changing climate• A research collaboration Tsing hua university and RU-CORE• Funded by the Natioanl Research Council of Thailand.

GCMs data set
RegCM4

Bias Correction

Met data

Climate Dataset

Land use data

WEAPImpacts

Hydro data

GBEHM

Water mangmnt.

Other data

CORDEX SEA Domain and Study area

Climate data set• Dynamical Downscaling

RegCM4• Domain• Base line
• Projection

CORDEX-SEA
1970 – 2005
2006 - 2060

• Resolution• GCMs– MPI-ESM-MR– EC-Earth– GFDL-ESM-2M• Scenario

25 km x 25 km
Max Planck Institure for Meteorology

EC-Earth consortium
GFDL, USA
RCP4.5 and RCP8.5

Training/Workshop

Jiulong
River Bain

Chao Praya RiverBasin

Geomorphology-based ecohydrological model (GBEHM)

WEAP Chao Phraya Model• No. of provinces : 29
• Total area : 158,586 km2• Grid resolution : 25 km x 25 km• No. of grid : 316

Main rivers and canels
8 main rivers• Ping river• Wang river• Yom river• Nan river• Sakae Krang river• Pa Sak river• Tha Chin river• Chao Praya
16,412 branch rivers andcanels

River (8)19422011
2XXX ?!

PastNow

THANK YOU