Recent interdecadal shift in the relationship between Northeast China’s winter precipitation and the North Atlantic and Indian Oceans

Abstract

This study documents an interdecadal change in the interannual relationship between Northeast China’s winter precipitation (NECWP) and the sea surface temperature (SST) in the North Atlantic and Indian Oceans in the 1990s. It is revealed that the NECWP shows a significant simultaneous correlation with the SST anomalies in the North Atlantic (SST_Atlantic)/tropical Indian Ocean (SST_Indian) during 1996–2013/1961–1990. Generally, the NECWP anomaly is concurrent with apparent Eurasian wave pattern during 1961–1990 whereas anomalous Okhotsk high and East Asia trough during 1996–2013. It is found that, before the 1990s, the warming SST anomalies in the tropical Indian Ocean could stimulate the Eurasian wave pattern via inducing significant anomalous upper-level convergence over the northern Europe, which tends to favor a positive NECWP anomaly. During 1996–2013, the SST_Indian-NECWP connection is disrupted. Instead, the North Atlantic tri-polar SST anomaly pattern exerts a dominant impact on the NECWP through triggering a stationary Rossby wave that originates from the North Atlantic and propagates eastward to Northeast Asia and further modulates the Okhotsk high and East Asia trough. Further analyses indicate that the weakened connection between the tropical SST_Indian anomalies and the northern Ferrell circulation likely contributes to the weakening of the NECWP–SST_Indian relationship after the 1990s. However, the eastward shift and the enlarged anomalous magnitudes of the North Atlantic Oscillation might favor the strengthening of the NECWP–SST_Atlantic relationship after the mid-1990s. It is therefore suggested that the strengthened variability of the SST_Atlantic anomalies after the 1990s might partially contribute to the intensification of the interannual variability of the NECWP.