exploring decadal to century scale variability and changes ...folk.uio.no/kkv/24. aug/15.15 -...
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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)
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SIA
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East Asia Summer Monsoon (EASM) vs. Arctic Sea Ice
Precipitation & Arctic Sea Ice
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(b) Corr. Precip.&SIAI
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150 E
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105 E 135
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(b) Corr. Precip.&SIAI
150 E
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105 E 135
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30 N
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(a) Corr. Precip.&EASMI
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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
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120 E 180
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(b)Pr.SeaIce AOGCM JJA
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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 !