Impacts of Atlantic sea surface temperature anomalies on Indo-East Asian summer monsoon-ENSO relationship

Abstract

In this study, the effect of the tropical North Atlantic (TNA) sea surface temperature (SST) variation in inducing the circulation anomaly in the Indo-East Asian monsoon (IEAM) region is investigated through the observational analysis and numerical modeling. The observational analysis shows that the TNA summer SST is positively correlated with the preceding winter Niño3 SST and is simultaneously correlated with the circulation in the IEAM region. The simultaneous circulation pattern resembles that of the ENSO-decaying summer. The positive correlation between the TNA SST and the Niño3 region SST is primarily ascribed to the surface latent heat flux and short wave radiation anomalies induced by the ENSO teleconnection. Coupled general circulation model experiments show that, while including the air-sea coupling in the Atlantic, the model can reproduce the main features of the IEAM circulation, such as an anomalous anticyclone over the western North Pacific (WNP) and southerly anomalies over southeast China. While the climatological Atlantic SST is prescribed, the circulation over the WNP displays a significantly different pattern, with an eastward migration of the WNP anticyclone and the associated northerly anomalies over southeast China. It is argued that anticyclonic shear and Ekman divergence associated with the atmospheric Kelvin wave response to the TNA warm SSTA forcing is the primary mechanism for the generation of the anomalous anticyclone in WNP. The results presented in this study provide a teleconnection pattern between TNA and short-term climate variability in IEAM region. ENSO, Indian monsoon, East Asian monsoon, western North Pacific anticyclone, Atlantic Citation:Rong X Y, Zhang R H, Li T. Impacts of Atlantic sea surface temperature anomalies on Indo-East Asian summer monsoon-ENSO relationship.

Plausible influence of Atlantic Ocean SST anomalies on winter haze in China

“…Additionally, the anomalous westerly airflow from the tropical Atlantic to Africa-Indian Oceansouthern China and the two abnormal anticyclonic circulations across the tropical Indian Ocean may be related to the significant westerly airflow anomalies over southern China. Previous studies documented the relationship and physical processes linking the South Atlantic SST and the aforementioned circulation anomalies (Xie and Tanimoto 1998;Haarsma et al 2003;Robertson et al 2003;Rong et al 2010). These wave trains found in the anomalous horizontal winds that accompany SAI in the previous autumn (Fig.…”

A dynamical‐statistical forecast model for the annual frequency of western Pacific tropical cyclones based on the NCEP Climate Forecast System version 2

“…It has been suggested previously that the positive SST anomalies of the tropical North Atlantic are mainly due to the Pacific ENSO teleconnection at both interannual and decadal time scales [e.g., Enfield and Mayer, 1997;Chang et al, 1997;Huang et al, 2002;Liu et al, 2004;Hu et al, 2011]. More importantly, the tropical North Atlantic SST forcing is the main cause of the WNP anomalous anticyclones associated with reduced convections [Lu and Dong, 2005;Rong et al, 2010]. Thus, the interannual variations of WNP TCs are likely resulted from the changes in the planetary-scale atmospheric circulation associated with ENSO [Chan, 2007], which is consistent with the previous finding that there is no strong local correlation between the SST anomalies and TC activity over the WNP [e.g., Wang and Chan, 2002;Chan and Liu, 2004].…”

Enhanced relationship between the tropical Atlantic SST and the summertime western North Pacific subtropical high after the early 1980s

“…However, a remarkable change occurred in P2 (Figure 3b): first, the negative correlation with the EEP-SST shifted toward the central Pacific (5°S-5°N, 170°E-120°W); second, the SSTs in the NIO/WNP (0°N-20°N, 50-150°E) and TA (0°N-20°N, 25-80°W) became positively correlated with the WNPSH index. Previous studies [e.g., Yang et al, 2007;Wu et al, 2010] emphasized that the NIO-SST [e.g., Yang et al, 2007;Xie et al, 2009;Wu et al, 2010] and TA-SST [e.g., Enfield and Mayer, 1997;Alexander et al, 2002;Huang et al, 2002;Lohmann and Latif, 2007;Rong et al, 2010] tended to rise in response to the remote forcing by El Niño that started in preceding winter. However, the sliding (21 years window) correlation coefficients between the ENSO index (i.e., averaged SSTA over 5°S-5°N, 170°E-120°W) in previous winter and the TA-SST index and the NIO-SST index in boreal summer (Figure 4) show that the ENSO's lagged impact on heating the NIO-SST increase gradually and becomes more significantly after late 1970s.…”