Climate Change Scenario Analysis in Climate Change Scenario Analysis in the Future Over the Future Over western of China

Ying Xu Xuejie Gao Yun Gao

National Climate Centre, China

AIACC workshop, PhilippinesNov. 04, 2004

Outline• Part I: Possible Climate Change in Western China due to human activities by AOGCM

• Part II: Possible Climate Change in Western China due to human activities by RegCM (1) Climate Change in the future over China due to GHG (2) Impacts of Land-use Change on Climate in China

• Part III: next step work plan

Part I : Possible Climate Change in Western China due to human

activities by GCM

NCC/IAP T63

HADL

GFDL

CCCma

CSIRO

CCSR

Author Ying Xu et al (2003)

M itchell & Johns (1997)

Haywood et al. (1997)

Boer, et al. (2000a,b)

Gordon & O’Farrell (1997)

Emori et al. (1999)

AGCM 1.875X1.875/L16

3.75×2.5/L19

R15/L9 T32/L10 R21/L9 T21/L20

OGCM .875X1.875/L30

3.75×2.5/L20

4.0×3.75/L12

1.8×1.8/L29

R21/L21 2.8×2.8/L17

Models Description

A2: SRES scenario—A2B2: SRES scenario—B2

The change of temperature over western of China in 21st century (unit:℃)

1960 1980 2000 2020 2040 2060 2080 2100-4

-2

0

2

4

6

8

10

12

14

A2

1960 1980 2000 2020 2040 2060 2080 2100-4

-2

0

2

4

6

8

10

B2

Red: 5 model mean

Dark blue: Hadley

Sky blue: CCSR

Green: CCCma

Yellow: CSIRO

Pink: NCC/IAP

For 5 models mean, the temperature will increase about 8 under A2 ℃scenario in the end of 21st century, increasing is about 5 under B2 ℃scenario.

Annual change of temperature over western China (Unit :℃)

Region China South-West North-West

SRES-A2

2011~2040 1.4 1.2 1.6

2041~2070 3.0 2.6 3.3

2071~2100 4.9 4.4 5.6

SRES-B2

2011~2040 1.5 1.2 1.8

2041~2070 2.7 2.3 3.1

2071~2100 3.6 3.3 4.0

The change of precipitation over western of China in 21st century (unit:%)

1960 1980 2000 2020 2040 2060 2080 2100-30

-20

-10

0

10

20

30

40

50

60

A2

1960 1980 2000 2020 2040 2060 2080 2100-30

-20

-10

0

10

20

30

40

50

60

B2

Red: 5 model mean

Dark blue: Hadley

Sky blue: CCSR

Green: CCCma

Yellow: CSIRO

Pink: NCC/IAP

For 5 models mean, the Pr. will increase about 10% under A2 scenario in the end of 21st century, it will increase 8% under B2 scenario.

Annual change of precipitation over westarn China (Unit :%)

Region China South-West North-West

SRES-A2

2011~2040 1.4 1.2 1.6

2041~2070 3.0 2.6 3.3

2071~2100 4.9 4.4 5.6

SRES-B2

2011~2040 1.5 1.2 1.8

2041~2070 2.7 2.3 3.1

2071~2100 3.6 3.3 4.0

The seasonal precipitation change over western of China in 21st century (unit:%)

1960 1980 2000 2020 2040 2060 2080 2100-20

-10

0

10

20

30

40

50

60

70

A2

1960 1980 2000 2020 2040 2060 2080 2100-20

-10

0

10

20

30

40

50

60

70

B2

Red: annual mean

Dark blue: Spring

Sky blue: Summer

Green: Autumn

Yellow: Winter

The Pr. increasing is greater in winter and spring, change is little in summer and autumn under A2 and B2 scenarios.

The distribution of annual mean temperature change over western of China (2070~2099) (unit:℃）

The distribution of annual mean precipitation change over western of China (2070~2099) (unit:%）

• Warming is obviously in western of China, warming is exceed China mean value .

• Compared A2 scenario with B2, it shows a majority of warming under A2 scenario than B2, So depend on different greenhouse gases emission scenario, the climate will have different change in the future.

• The annual mean precipitation will increase in the end of 21st century.

• For different season, most obvious rainfall increase occurs in winter and spring， the increase in autumn and summer are little.

• For the spacial distribution, The precipitation has an increasing trend, especially in the Western China and North-western China region, while the increase is not so obvious in the Southwestern China

Part I : Conclusions

Part II

Possible Climate Change

in Western China due to the effect of human activities by RegCM

1881 1990

2070

Observed CO2 Concentration

GCM Run

5 year RCM CTL

12 h

5 year GCM CTL

5 year RCM

12h

5 year GCM

Model output was interpolated to 160 stations of China

(1) Possible Climate Change in China

Part Ⅱ

Annual mean Ts Change in China(unit: ℃)

Increase all over the area, with a higher increase in North China, it is obviously in western of China

Part Ⅱ

Annual mean Pr Change in China (unit: %)

Increase in most

areas, higher in NW

Part Ⅱ

Change of Annual mean rain days (%)

● ： -20 ～ 0

● ： 0 ～ 10

■ ： 10 ～ 20

Part Ⅲ

Conclusions :

• Ts in China will remarkably rises by 2.5oC, with

higher increase western of China

• Pr will also increase by about 25%.

• Increase of rain days in western of China.

Part Ⅱ

(2) Impacts of Land-use Change on Climate in China

Land-use changes a lot in China for its long agriculture

history and present big population pressure

Part Ⅳ

Landuse Change in China

▼: tree →shrub

▲: tree → irrigated crop farming

●: semi desert → desert

■: tree → crop/mixed farming

◆: grass→ rop/mixed farming

Areas of no change: 2: short grass 3: evergreen needleleaf tree

5: deciduous broadleaf tree 6: evergreen broadleaf tree 7: tall grass 8: desert

Part Ⅳ

Experiment Design:

5 year RegCM2 run driven by

5 year CTL run of AOGCM

Exp 1. With potential vegetation cover

Exp 2. With present vegetation cover

Exp2-Exp1,

was thought as the impact of landuse change on climate

Plotted and analysed in 160 station positions

Part Ⅳ

Change of Annual mean Ts (℃)

● ： -1.5 ～ 0

■ ： 0 ～ 1.5

Part Ⅳ

Change of Annual mean Pr (%)

■ ： <-20%

■ ： -20% ～0

● ： 0 ～ 20%

● ： >20%

Part Ⅳ

Dotted spots are stations with change passed 90% t - test, same as below

Change of Summer Tmax ( )℃● ： -2.4 ～ 0

■ ： 0 ～ 2.4

■ ： 2.5 ～ 4.4

◆ ： >4.5

Part Ⅳ

Change of Winter Tmin ( )℃● ： <-2.4

● ： -2.4 ～ 0

■ ： 0 ～ 2.4

■ ： >2.5

Part Ⅳ

Change of Annual mean Soil moisture (%)

■ ： -20 ～ 0

● ： 0 ～ 20

Part Ⅳ

Conclusions :

Current Landuse in China, may caused:

• Less rainfall in NW; • Temperatures increasing is in Sichuan basin and part of NW a

rea;• Increasing of summer Tmax in many places, Increasing of win

ter Tmin in NW;• Decrease of Soil moisture in many places, including western of

China;• Same landuse can cause different climate effect, depends on th

e geography character in the area.

Part Ⅳ

Part III Next step work

• Using dynamical downscaling is going to coutinue simulate various episodes in 21st Century with the regional climate model with the boundary conditions provided by the global model.

• To apply the simulation results of the global and regional climate models into a hydrological model, to simulate the future hydrological cycle over the Western of China.

• To provide the projected climate change simulations over the Northwestern China to the relative research groups for impacts and adaption.

The End