Uncertainties in Climate Change Projection –

An example of monsoon precipitation over China as simulated by 2 simulations of a RCM

GAO Xuejie

National Climate Center, China Meteorological Administration

International Conference on Climate Change Adaptation: Policy, Practice & LegislationBeijing, 2-4 July 2013

Uncertainties in the future emission scenarios

Natural variability

Incomplete knowledge of the climate and earth system which lead to the imperfect models

Incomplete knowledge of some external factors in the future: solar, volcano, etc.

More uncertainties in the regional scale: landuse, aerosol, lack of enough observation, etc.

Multi-model ensemble is a good way to address some of the uncertainties

Source of the uncertainties:

SRES scenario RCP scenario

Annual mean surface air temperature as simulated/projected CMIP5 multi-models over China ( )℃

CMIP5 ProjectionsCMIP5 Projections

Annual mean precipitation as simulated/projected CMIP5 multi-models over China (mm)

RCM: the ICTP RegCM3 in both simulations, same configurations, similar domain

FdR： Driving field: NCAR/NASA FvGCMSimulation period: presenet day 1961-1990, future 2071-2100Scenaior: SRES A2; Resolution: 20×20km

MdR： Driving field: CCSR/NIES/FRCGC MIROC3.2_hiresSimulation period: 1951-2100Scenaior: SRES A1B; Resolution: 25×25km

Period of analysis: May-June-July-Ausgus-September, Present: 1961-1990, Future: 2071-

2100 Observation: Precipitation: Xie et al. (2007), Temperature: CN05 (Xu et al., 2009)

RegCM3 simulations driven by FvGCM and MIROC: Uncertainties in monsoon precipitation projections over China: results from 2 RCM simulations

Mean precipitation in MJJAS for 1961-1990 ( ). (a) Observations; and simulations by ℃FvGCM (b), by FdR (c); by MIROC (d); by MdR (e)

Simulated changes in mean temperature (ºC) for MJJAS by (a) FvGCM; (b) FdR; (c) MIROC; (d) MdR

Agreement in the sign of projected precipitation change across model simulations. (a) between FvGCM and MIROC; (b) between FdR and MdR. Blue

(red) indicates that both models simulate a >5% increase (decrease)

ACCC RCM study for uncertainties - 2 RCM driven by 2 GCM:

HadCM3-Q0 – RegCM4

HadCM3-Q0 – PRECIS

ECHAM5 – RegCM4

ECHAM5 – PRECIS

谢 谢 !THANK YOU!