exploring decadal to century scale variability and changes ...folk.uio.no/kkv/24. aug/15.15 -...

East Asia DecCen: Exploring Decadal to Century Scale Variability and Changes in the East Asian

Climate during the last Millennium A multi-disciplinary study of observed and modelled variations in climate in East Asia, in response to the RCN’s call Climate change – research collaboration with

China

Project leaders: Prof. Tore Furevik, Geophysical Institute and Bjerknes Centre for Climate Research, University

of Bergen, Norway (BCCR-UoB) Prof. Hui-Jun Wang, Institute of Atmospheric Physics/Chinese Academy of Sciences, Beijing,

China

Main objective: To identify regional and remote causes for variations

in temperature, drought and flooding patterns over East Asia, and to

reduce the level of uncertainty in climate projections.

Budget: 7.1 MNOK (7,8 MCNY) for Jul 2009 – Mar 2013

• Module 1 – Project management and coordination Responsible: Yongqi Gao (NERSC/BCCR) and Jianqi Sun (IAP/CAS)

• Module 2 – Reconstructed and observed decadal to centennial variability in East Asia and Northern Hemisphere climate Responsible: Atle Nesje (UoB), Meixue Yang (CAREERI)

• Module 3 – Modelled climate variability in East Asia Responsible: Odd Helge Otterå (BCCR-UNI) and Tian-Jun Zhou (IAP/CAS)

• Module 4 –Exploring concerted climate variability over North Atlantic-East Asia Responsible: Yvan Orsolini (NILU), Shuanglin Li (IAP/CAS), and Nils Gunnar Kvamstø (BCCR-UoB)

• Module 5 – Synthesis Responsible: Eystein Jansen (BCCR-UNI), Hui-Jun Wang (IAP/CAS), and Tore Furevik (BCCR-UoB)

Modules and module responsible

Teleconnection and External Forcing of Asian Monsoons

Towards a better understanding and prediction of

Asian Monsoons

Yongqi Gao1,2,4,5 and co-authors1,2,3,4,5

1 Nansen Environmental and Remote Sensing Centre 2 University of Bergen

3 Uni Research 4 Bjerknes Centre for Climate Research

5 Nansen-Zhu International Research Centre, Beijing, China

Outline

Background

Asian Monsoon and High Latitude Forcing

Asian Monsoon and Atlantic Forcing

High-and-lower-latitude forcings

Conclusions and discussions

Indian Summer Monsoon

http://www.aau.ac.in/dee/Monsoon.php

http://www.pinterest.com/pin/508203139172175846/

East Asia Summer Monsoon: Shift in Precipitation

Xinhua

Factors Impacting Asia Monsoons Eurasian land surface temperature, including Tibet Plateau

ENSO and PDO

Siberian snow cover

Vegetation

Upper troposphere cooling

North Atlantic SST

Antarctic Oscillation

Indian Ocean SST

Arctic Oscillation

Arctic Sea Ice

Asian Monsoon and Northern High Latitude Forcing: Arctic Sea

Ice and Arctic Oscillation

Arctic Sea Ice and Climate (Weather)

• Bodikova (2009)

• Bader et al. (2011)

• Vihma (2014)

• Cohen et al. (2014)

• Gao et al. (2015)

• Overland et al. (2015)

• Jung et al. (2015)

-0.4

-0.2

0

0.2

0.4

Sep

.

Oct.

No

v.

Dec.

Ja

n.

Fe

b.

Ma

r.

Ap

r.

Ma

y.

Ju

n.

Ju

l.

Au

g.

Co

rrela

tio

ns

-2

0

2

AS

MI

ASMI

1980 1985 1990 1995 2000 2005

-2

0

2

SIA

In

dex F

MA

SIA

East Asia Summer Monsoon (EASM) vs. Arctic Sea Ice

Precipitation & Arctic Sea Ice

150 E

60 N

120 E

45 N

30 N

105 E 135

E

15 N

(b) Corr. Precip.&SIAI

150 E

45 N

105 E 135

E 120

E

30 N

15 N

60 N

(a) Corr. Precip.&EASMI

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

150 E

60 N

120 E

45 N

30 N

105 E 135

E

15 N

(b) Corr. Precip.&SIAI

150 E

45 N

105 E 135

E 120

E

30 N

15 N

60 N

(a) Corr. Precip.&EASMI

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Guo, D., Gao, Y.Q., Bethke, I., Gong, D.Y., Johannessen, O.M., Wang, H.J., 2014. TAC

Bergen Climate Model (v2) (Otterå et al., 2009)

• ARPEGE – Resolution: T42, ~2.8x2.8, 31 layers

– Volcanic aerosols implemented

• MICOM – Resolution: ~2.4x2.4, 35 isopycnic

layers

– Reference pressure at 2000 m

– Incremental remapping for tracer advection (better conservation)

• Thermodynamic and dynamic sea-ice module (GELATO) – Multi-ice categories

• No carbon cycle or vegetation!

ARPEGE

MICOM

Arctic Sea Ice & Precipitation

150 E

60 N

120 E

45 N

30 N

105 E 135

E

15 N

(b) Corr. Precip.&SIAI

150 E

45 N

105 E 135

E 120

E

30 N

15 N

60 N

(a) Corr. Precip.&EASMI

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0.5 0.1

0.3

0.3

0.1

-0.10.1

0.1

-0.1

120 E 180

E

15 N

30 N

45 N

150 E

60 N

(b)Pr.SeaIce AOGCM JJA

·

Gong, D.Y., Yang, J., Kim, S.J., Gao, Y.Q. Guo, D., Zhou, T.J., Hu, M. 2011, Climate Dynamics

Spring Arctic Oscillation and East Asia Summer Monsoon

Conclusions

• The SST in North Pacific bridge the spring Arctic sea ice cover and the East Asian summer monsoon precipitation

• The mediating role of SST changes is highlighted by the result that only the AOGCM, but not the AGCM, reproduces the observed sea ice-EASM linkage

AO and East Asia Winter Monsoon

Li, F., Wang, H,J, Gao, Y,Q. 2014, Journal of Climate

Sea Ice Impact: Eurasian Cooling (CAM3)

Li, F., Wang, H,J, Gao, Y,Q. 2014, Journal of Climate

Conclusion

• Autumn Arctic sea ice reduction leads to Eurasian cooling. It in turn results in westward extension of EAJS and bridge the AO and EAWM

Li, F., Wang, H,J, Gao, Y,Q. 2014, Journal of Climate

Asia Monsoon and Atlantic Forcing

Inter-decadal Shift in Precipitation in East China

1978-1995 minus 1958-1977 differences of JJA precipitation (mm/d)

Wang, T., Wang, H.J., Otterå, O.H., Gao, Y.Q., Suo, L.L., Furevik, T., Yu, L. 2013, ACPD

ISM and NAO:External Forcing

NAO and ISM is Under-Debate

Inverse relationship (Dugam et al., 1997)

Positive relationship (Goswomi et al, 2006)

No relationship (Li, et al., 2008)

NAO and ISM from Reconstructed Data

NAO and Rainfall (Model)

Indian Rainfall and Volcanic Eruptions

ISM and Volcanic Eruptions

NAO and Volcanic Eruptions

Volcanic eruptions typically led to strengthened ISM circulation and ISM rainfall at the 3rd year after volcanic eruptions;

External forcing factors, by affecting both the Indian Ocean SST and the winter NAO, could likely produce a stronger statistical but not causal relationship between the winter NAO and the ISM rainfall on inter-decadal timescale.

Conclusions

Cui, X.D., Gao, Y.Q., Sun,J.Q., Guo, D., Li, S.L., Johannessen, O.M. 2014

Asia Monsoons: high-and-lower latitude forcings

Li, F., Wang, H.J., Gao, Y.Q., 2015

Extratropical Ocean Warming and Winter Arctic Sea Ice Cover

since the 1990s

Arctic Sea Ice (winter): Predictability

Heat and moisture transport

Pre-seasonal reduction

Inflows of Atlantic and Pacific water

Ice export

Motivation (a) E T-S S T E O F1 (1870-2012)

(b) E T-S S T P C 1

The period from 1994 to 2013

Extra-tropical (ET) SST and Arctic sea ice (observation)

Teleconnection of ET warming (detrended) Arctic sea ice cover Air temperature at 2 m

NCAR-CAM3 Experimental design (Exp.1)

1 CAM3 is forced by climatological and monthly-mean SST and sea ice (1979–2010) 2 For extra-tropical oceans (20°N–70°N), the model is forced by the observed 35-yr (from January 1979 to December 2013, 35 × 12 months). 3 10 members

Simulated quantities regressed to ET-SST PC-1 during 1994–2013

Surface air temperature 850-hPa horizontal heat flux

NCAR-CAM3 Experimental design (Exp.2, 3 and 4)

Exp.2, control simulations in which CAM3 is forced by climatological monthly mean SST and sea ice (1979–2010)

Exp.3, sensitivity simulations in which CAM3 is forced by perturbed winter ET-SST (20°N–70°N)

Exp.4, sensitivity simulations in which CAM3 is forced by perturbed winter NP-SST (110°E–110°W, 20°–70°N);

Simulated impact of ET-SST (Exp.3 minus Exp.2)

Simulated impact of NP-SST (Exp.4 minus Exp.2)

Conclusion There is a statistical linkage between the

extra-tropical warming and winter Arctic sea ice from 1994 to 2013.

The winter extra-tropical warming (in particular, the warming in the Pacific) can influence the winter Arctic sea ice cover by strengthening the polar vortex and modulating the near surface atmospheric heat transport.

Discussions Interaction between the Arctic and

lower latitude climate and the response to external forcing

Asian monsoon predictability: Arctic versus tropical forcings

Thank you !