Session-5: CORDEX-Asia ESD
16:00-16:20 5-1 Koji Dairaku“Hi-Resolution Multi-Ensemble Statistical Downscaling Regional
Climate Scenarios”

16:20-16:40 5-2 Nuzba Shaheen
Performance Evaluation and Statistical Downscaling of CORDEX
RCMs for Impact Assessment Studies in South Asia and South
East Asia

16:40-17:00 5-3 Shaukat Ali
Future Projections of Climate Extremes over Pakistan using QM,
DQM and QDM Statistical Downscaling/Bias-Correction

17:00-17:20 5-4 Ashwini Aniruddha Kulkarni
Statistical Downscaling for South Asian Region

17:20-17:40 5-5 Seonae Kim
Statistical Downscaling for Daily Precipitation in Korea using
Combined PRISM RCM，and Quantile Mapping: Part 1.
Methodology and Evaluation in Historical Simulation.
Follow-up discussions at Dinner Meeting on 3rd and Planning Meeting on 4th

Hi-resolution multi-ensemble statistical
downscaling regional climate scenarios
and CORDEX Asia ESD
Koji DAIRAKU
National Research Institute for Earth Scienceand Disaster Resilience, Japan
2-4th Oct 2017, Tsukuba

Backgrounds of developing regional climate scenarios The Asia-Pacific region are increasingly threatened by large scale
natural disasters. Growing concerns that loss and damages ofnatural disasters are projected to further exacerbate by climatechange and socio-economic change.
 The Paris Agreement dealing with greenhouse gas emissions
mitigation and adaptation entered into force in 2016. National
Plan for Adaptation to the Impacts of Climate Change wasendorsed by the Japan Cabinet in 2015. Sustainable
Development Goals(SGDs) set targets of 17 goals (includeclimate action) to be achieved over the next 15 years in 2015.
 Fundamental regional climate information is indispensable forunderstanding changing climate and making decisions on whenand how to act.
 Spatio-temporal comprehensive and consistent information isnecessary and useful for decision making.

CORDEX (Coordinated Regional Climate Downscaling Experiment)
Scientific Vision: To advance and coordinate the science andapplication of regional climate downscaling through globalpartnerships

 Scientific Challenges: Added value, Human element,
Coordination of regional coupled modelling, Precipitation,
Local wind systems

 Flagship Pilot Studies (FPS) 2016- (Selection: 3 times/year）• SAM: Extreme precipitation events• EUR+MED: Convective phenomena• EUR: Impact of Land use changes on climate• MED: Role of the natural and anthropogenic aerosols• MED: Role of air-sea coupling and small scale ocean processes on theregional climate

CORDEX (Coordinated Regional Climate Downscaling Experiment) Climate Service
・Partnership with World Meteorological Organization (WMO) Global Framework for Climate Services (GFCS)・Climate Service Center Germany
Site-characteristic Climate-Fact-Sheet
Climate Signal Maps
Web-based climate service productwww.atlas.impact2c.eu

・Earth System Grid Federation (ESGF) regional nodes: Japan,India （Under developing: Korea, Thai）

What is downscaling?
 A lot of regional downscaling research activities
CORDEX, PRUDENCE, ENSEMBLES, PIRCS, NARCCAP, MRED,RMIP, S5-3, SOUSEI, SI-CAT, CCSN, etc.

 Dynamical downscaling+ Based on physics, Output variables are physically consistent,physical interpretation.
- relatively large bias (effects of systematic errors in the driving large
scale fields), computationally expensive.

 Statistical downscaling+ relatively accurate, simple, computationally economical, provide
specific local information by tailored model (e.g., points, catchments).
- Not based on physics, assumption of stable climate (cannot accountfor possible systematic changes or feedback processes), lessconsistency between different variables.
Dynamical and statistical downscaling methods are complementary.

Multi-model ensemble experiment• Ensemble downscaling experiment by multiregional climate models to investigate therange of structural uncertainty

e.g., Iizumi et al., JGR 2011, Ishizaki et al., JMSJ, 2012, 2012b, Iizuka, Dairaku et al., JMSJ, 2012, Iizumi et al.,
JGR, 2012, Sasaki et al., JMSJ, 2012, Tsunematsu et al., JGR, 2013; Nayak, Dairaku, HRL, 2017; Nayak,Dairaku et al., Clim. Dyn. in print.
CORDEX-EA(RMIP)： Tang et al., Int. J. Clim., 2016; Li et al., Int. J. Clim., 2016, Niu et al., Int. J. Clim., accepted.

Future scenario of extreme precip.
 Future projected changes of
the Clausius-Clapeyron(CC) relationship overJapan by using multi-model
ensemble downscaling
experiments(3RCMsx3GCMs, RCP4.5)
 Peaks pf extreme
precipitation linked totemperatures(19-22℃).
 The peak of extreme
precipitation intensities withtemperatures is projected toshift about 2℃(20℃→22℃).
 Insufficient water vapor
supply for saturation at
higher temperatures cancause less formation ofclouds and extreme
precipitation.
Nayak, Dairaku et al., Clim. Dyn. in print.

(Dec2015-Mar2020)

Develop multi-model ensemble nearterm regional climate scenarios with
1km horizontal grid-spacing over Japanby dynamical and statistical
downscaling methods to support
various regional adaptation measures

ESD Output Sample(BCSD, Wood et al. 2002, Wood et al. 2004, Maurer et al. 2008)
MIROC5 Original
1degree Regridded

Bias corrected

Downscaled10Projected future change of annual precipitation（pr, Daily）
Ensemble average
37 models (CMIP5, RCP8.5, 2026-2050)

Standard Deviation

Ratio of models ofincrease/decrease change11

 Each model projected different responses because of structural differences.
 The most models show increase of precipitation (qualitative consistentency) .
 Working on multi-methods ensemble
Dairaku, in prep.

Probability map of 2m air temperature
Mean temp.

90%ileOver 2K

RCP8.5
40GCMsOver 4KJJA

DJF

Very high probability of a temperature increase in excess of 2K (Over 90%)High probability (50-80%) of 4K excess in most areas by the end of the 21stcentury (using Regression Method：Elastic Net)
(Ishizaki, Dairaku, Ueno, HRL, 2017)

ΔT>2K

ΔT>4K

Future(A1b)-PresentProbability map of 2m Temperature (2069-2098)-（1969-1998)

JanJulAnnualContributed to the report by the Ministry of Foreign Affairs in Japan for G7 Working
Group on Climate Change and Fragility (Sep 6th 2017 press release)Establish CORDEX Asia EmpiricalStatistical downscaling (ESD) group
Background & Motivation• Regional climate information and service isrequired for risk assessment on sub-national scale
for climate change adaptation and IPCC AR6.
• Dynamical downscaling and Empirical-Statisticaldownscaling (ESD) can complement each other.
• Establish ESD group for well coordinateddownscaling activities in Asia to find additional
strength to support for what we are doing inisolation.
• What are the key needs? What is driving ourscience at current.

CORDEX Asia Empirical-Statistical downscaling (ESD) group
Current Members of CORDEX Asia-ESD group
Group Leader: Koji Dairaku (NIED, JAPAN)

2016/11/23

China: Ailikun (Co-chair: ITP/CAS), Lianhua Zhu(NUIST), Lijun Fan (IAP/CAS)
India: Ashwini Kulkarni (IITM)
Indonesia: Ardhasena Sopaheluwakan (BMKG),
Muhammad Ridho Syahputra (ITB)
Japan: M. Nishimori (NIAES), N. Endo (NIAES),
A. Yatagai (APHRODITE-2, Hirosaki Univ.)
Korea: Hyunhan Kwon (Chonbuk Nati. Univ.)
Malaysia: Liew Juneng (Malaysia National Univ.),
Ester Salimun (Univ. of Malaysia)
Pakistan: Nuzba Shaheen, Shaukat Ali (GCISC)
Philippines: Francia B. Avila (Ateneo de Davao Univ.)
Singapore: Bertrand Timbal (CCRS)
Sweden: Iréne Lake (SMHI)
Taiwan: Cheng-Ta Chen (NTNU), Chao-Tzuen
Cheng, (NCDR)
Thailand: Jerasorn Santisirisomboon(Ramkhamhaeng Univ.), Chakrit Chotamonsak(Chiang Mai Univ.)
Vietnam: Quang Dinh (VNCWE)• Integrating the science and application of downscaling activities in Asia
(EA,SEA,SA etc.) to provide regional climate information and service forrisk assessment and IPCC AR6.
• A common benchmark for investigating uncertainty of regional climate
scenarios and risk analyses.

Main possible activities and goals ofthe CORDEX Asia ESD group
Produce regional climate statistical downscaling information basedon common protocols for a common benchmark for investigating
uncertainty of regional climate scenarios.
Case studies in small domain for developing and improving themethods where sufficient observation is available (e.g., city, coastal
areas, agricultural lands, etc.) and for obtaining best/good practices ofco-production /coordination with IAV community.
Improve reference data for improving ESD and DDS skills bycollecting better observational data and its update.
Training workshops to share and exchange knowledge andtechniques.

Enhance well-coordinated downscaling activities in Asia toprovide regional climate information and service which isrequired for risk assessment on sub-national scale for climatechange adaptation and IPCC AR6.

Discussions

How can we move forward from “Garbage in – garbageout” to “Garbage in or Excellence in - excellence out”?
 Added Value:
ESD from the parent global model should be used as the benchmark(control) with which dynamic downscaling would have to improve on.
(e.g., Iizumi et al., JGR, 2011)

 Scale dependence of downscaling
Downscaling over complex terrain/coastal areas/land cover wheredynamics and physics interact.

 Implications of future scenario
Is the current assumption: “invariance of model bias under climatechange” valid? Model bias is larger in higher temperature.
What are deterministic and statistical metrics? Should we conserve“trend”?

 Convection permitting (cloud resolving model)
be panacea for regional climate downscaling, in particular on subdaily time-scale? ESDs can add values?

Summary and Issues
Multi-model ensemble downscaling experiments inJapan and CORDEX-EA.
Added values, Extreme events, Future projection, Uncertainty, etc.

Develop Hi-resolution large ensemble statistical
downscaling and probabilistic regional climate
information
Uncertainty in climate scenario ensemble experiments.

Bottom-up process and risk-based approach(SI-CAT)
Include more regional stakeholders to develop regional climate
scenarios for policy-relevance.

Establish CORDEX Asia ESD group.
・A common benchmark and stocktake for a rich diversity ofmulti-model/method ensembles and for investigating uncertainty ofclimate scenarios and climate risks.
・Reduce a timeline gap from CMIP6 to regional risk analyses forpossible interlink of IPCC with national/regional climate adaptation.