Spring Arctic Sea Ice impacting the East Asia summer precipitation

The paper Mechanism on how the spring Arctic sea ice impacts the East Asian summer monsoon has been published in Theoretical and Applied Climatology jointly between scientists at the Nansen-Zhu International Research Center in Beijing, the Nansen Center in Bergen and the Bjerknes Centre. Observational analysis and purposely designed numerical experiments with the coupled atmosphere–ocean (AOGCM) and atmosphere only (AGCM) models has been performed to investigate a new mechanism describing how spring Arctic sea ice impacts the East Asian summer monsoon (EASM). Consistent with previous studies, analysis of observational data from 1979 to 2009 show that spring Arctic sea ice is significantly linked to the EASM on inter-annual timescales (see Figure).Correlations between the precipitation and EASM (a) and between precipitation and the spring Arctic sea ice area (b). Note their opposite sign.Correlations between the precipitation and EASM (a) and between precipitation and the spring Arctic sea ice area (b). Note their opposite sign.

Observational analysis reveal that sea surface temperature (SST) changes in the North Pacific play a mediating role for the inter-seasonal connection between spring Arctic sea ice and the EASM. Large-scale atmospheric circulation and precipitation changes are consistent with the SST changes. The mechanism found in the observational data is confirmed by the numerical experiments and can be described as follows: spring Arctic sea ice anomalies cause atmospheric circulation anomalies, which, in turn, cause SST anomalies in the North Pacific. The SST anomalies can persist into summer and then impact the summer monsoon circulation and precipitation over East Asia. 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.

Sitation: Guo, D., Gao, Y.Q., Bethke, I., Gong, D.Y., Johannessen, O.M., Wang, H.J. 2013 Mechanism on how the spring Arctic sea ice impacts the East Asian summer monsoon. Theoretical and Applied Climatology, DOI: 10.1007/s00704-013-0872-6.

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