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Role of External Forcing Factors in Modulating the Indian Summer

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Role of External Forcing Factors in Modulating the Indian Summer Teleconnection and External Forcing of Asian Monsoons Yongqi Gao1,2, Xuedong Cui2 1 Nansen Environmental and Remote Sensing Center, Bergen, Norway 2 Nansen-Zhu International Research Center, Beijing, China Indian Summer Monsoon http://www.aau.ac.in/dee/ http://www.pinterest.com/pin/50 Monsoon.php 8203139172175846/ 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 High Latitude Forcing: Arctic Sea Ice and Arctic Oscillation East Asia Summer Monsoon (EASM) vs. Arctic Sea Ice 0.4 0.2 0 -0.2 Correlations -0.4 Jul. Oct. Jan. Feb. Mar. Apr. Jun. Sep. Nov. Dec. May. Aug. 2 -2 0 0 ASMI -2 2 SIA Index FMA FMA SIAIndex 1980 1985 1990 1995 2000 2005 ASMI SIA Precipitation & Arctic Sea Ice (a) Corr. Precip.&EASMI (b) Corr.(b) Precip.&SIAI Corr. Precip.&SIAI (a) Corr. Precip.&EASMI 1 1 60 N 60 N 60 N 0.8 60 0.8 N 0.6 0.6 0.4 0.4 45 N 45 N 45 N 45 N 0.2 0.2 0 0 -0.2 -0.2 30 N 30 N 30 N 30 N -0.4 -0.4 -0.6 -0.6 15 N -0.8 15 N 15-0.8 N 15 N -1 -1 105 E 120 E 135 E 150 E 105 E 105 120 E E 120 135 E E 135 150 E E 150 E 105 E 120 E 135 E 150 E Guo, D., Gao, Y.Q., Bethke, I., Gong, D.Y., Johannessen, O.M., Wang, H.J., 2014. TAC Spring Arctic Oscillation and East Asia Summer Monsoon · Gong, D.Y., Yang, J., Kim, S.J., Gao, Y.Q. Guo, D., Zhou, T.J., Hu, M. 2011, Climate Dynamics Arctic Oscillation and Tropical Indian Ocean Precipitation R(AO,CMAP)= + 0.56; R(AO,OLR)= - 0.61 Gong, D.Y., Gao, Y.Q., Guo, D., Mao, R., Yang, J., Hu, M., Gao, M.N. 2013 Climate Dynamics 9 East Asia Summer Monsoon (EASM) vs. Arctic Sea Ice He, S.P., Gao Y.Q., Furevik T. et al. Submitted to AAS Asia Monsoon and Atlantic Forcing Reduced AMOC and Asia Summer Monsoons Precipitation Yu, L., Gao, Y.Q., Wang, H.J., Guo, D., Li, S.L, 2009. Chin. Sci. Bull. ISM and NAO:External Forcing Aerosols and Atlantic SST (Booth et al., 2012 Nature) Simulated AMOC Response Strengthened AMOC in post-volcano years (pvy) Otterå, O.H., Bentsen, M., Drange, H., Suo, L.L. 2010, Nature Geosci. Courtesy of Odd Helge Otterå Volcano and PDO Wang, T., Otterå, O.H., Gao, Y.Q., Wang, H.J., 2012 Climate Dynamics Aerosol and 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, ACP PDO (1901-2015) http://ds.data.jma.go.jp/tcc/tcc/products/elnino/decadal/pdo_doc.html NAO and ISM is Under- Debate Inverse relationship (Dugam et al., 1997) Positive relationship (Goswomi et al, 2006) No relationship (Li, et al., 2008) Indian Rainfall and Volcanic Eruptions NAO and ISM from Reconstructed Data Conclusions 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. Cui, X.D., Gao, Y.Q., Sun,J.Q., Guo, D., Li, S.L., Johannessen, O.M. 2014 .
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