Responses of atmospheric circulation to sea surface temperature anomalies in the South China Sea

M P Zhou,G H Wang

doi:10.5194/os-11-873-2015

Abstract

Abstract. The sea surface temperature (SST) anomalies in the South China Sea (SCS) and their influences on global atmospheric circulation were studied. The results of a simple atmospheric model suggested that the SCS SST anomalies can induce several barotropic wave trains from the SCS to other regions such as North America, high latitudes of the Southern Hemisphere and the Mediterranean. The baroclinic stream function anomalies from the simple model showed an anticyclonic vortex pair in the Asian continent and the northern and southern Indian Ocean and a cyclonic vortex in the North Pacific and the southwestern Pacific. It is suggested that the spatial pattern of SST anomalies in the SCS can affect the magnitude of stream function anomalies, although it cannot affect the spatial pattern of atmospheric circulation.

Highlights

The South China Sea (SCS, 0–25◦ N, 100–125◦ E) is the largest marginal sea in the northwestern Pacific
The first one is from the SCS to North America through the northwestern Pacific, which is somewhat similar to the classical Pacific– North American (PNA) pattern (Wallace and Gutzler, 1981; Nitta, 1986; Huang, 1984)
The second one is from the SCS to high latitudes of the Southern Hemisphere across the Equator

Summary

Introduction

The South China Sea (SCS, 0–25◦ N, 100–125◦ E) is the largest marginal sea in the northwestern Pacific. The diabatic heating anomaly over the central equatorial Pacific during ENSO (El Niño–Southern Oscillation) can excite a stationary barotropic Rossby wave train propagating into extratropical regions This teleconnection is known as the Pacific– North American (PNA) pattern (Wallace and Gutzler, 1981) in the Northern Hemisphere. Nitta (1987) found another teleconnection between abnormal convective activity over the tropical, western North Pacific and atmospheric circulation anomalies over the mid-latitudes of East Asia in summer, which was named the Pacific–Japan (PJ) pattern. These studies mostly discussed how the SST in the SCS affected the local climate.

Data and method

Atmospheric model

Experiment setup

Influence of SST anomalies in the meridional direction

Influence of SST anomalies in the zonal direction

Summary and discussion