Influence of Atlantic Sea Surface Temperature patterns on Asian Summer Climate

Are the linkages between Atlantic variability and South/East Asia climate sensitive to the Sea Surface Temperature (SST) anomaly patterns in either the North Atlantic or elsewhere?

Atlantic Sea Surface Temperature Graph

Our new paper in the Journal of climate addresses this issue.

Our findings show that the Atlantic multidecadal oscillation (AMO) influences the summer climate of East Asia through an extratropical atmospheric circulation pathway (i.e. Rossby wave train), whereas South Asian summer monsoon precipitation is linked to the AMO partly via a tropical pathway (i.e. a change in the Intertropical Convergence Zone). 

These tropical and extratropical pathways that cause a response of the South and East Asia summer climate to the AMO are sensitive to the pattern of AMO SST anomalies, and to whether they are confined to the North Atlantic/Arctic or outside the North Atlantic. Even those SST anomalies outside the North Atlantic may still be associated with the AMO.

Overall in the South and East Asia region, temperature has a linear response to the strength and sign of the AMO North Atlantic SST anomaly, but the precipitation response is nonlinear—particularly when comparing across the negative and positive phases of the AMO.

The results obtained in this study help in understanding further the potential for the AMO to generate multidecadal variability in South and East Asian climate.

Find out more:

Ratna, S. B., T. J. Osborn, M. Joshi, and J. Luterbacher, 2020: The Influence of Atlantic Variability on Asian Summer Climate Is Sensitive to the Pattern of the Sea Surface Temperature Anomaly. J. Climate, 33, 7567–7590, https://doi.org/10.1175/JCLI-D-20-0039.1.