Authors:

Fangxing Fan,¹*  Xiao Dong,¹ Xianghui Fang,² Feng Xue,¹ Fei Zheng¹ and Jiang Zhu¹

¹ International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China

² Institute of Atmospheric Sciences, Fudan University, Shanghai, China

*Correspondence to: F. Fan, International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. E-mail: fanfangxing@mail.iap.ac.cn

Abstract:

Based on the observational and reanalysis data, El Ni？o warming patterns associated with the South Asian summer monsoon droughts are investigated. While the inverse relationship between the eastern Pacific (EP) type of El Ni？o-Southern Oscillation (ENSO) and the Indian monsoon rainfall weakened significantly, the correlation between the central Pacific (CP) type of ENSO and the monsoon rainfall strengthened after the late 1970s. Moreover, the drought-producing El Ni？o warming pattern also exhibits a notable decadal modulation associated with the climate shift. The analysis results indicate that both the EP type of El Ni？o with positive sea surface temperature (SST) anomalies extended to the date line and the CP type of El Ni？o with the maximum warming located in the central equatorial Pacific may produce severe droughts over the Indian subcontinent. Although the CP warming is more effective in driving anomalous rising motion in the central equatorial Pacific and consequently producing anomalous subsidence over South Asia, the position and strength of the anomalous ascending and descending branches of the Walker circulation are sensitive to the detailed distributions of tropical SST anomalies and determined by the competing effects of the CP and EP warming.

Key words:

South Asian summer monsoon; eastern Pacific El Ni？o; central Pacific El Ni？o; El Ni？o warming pattern; decadal transition

Citation:

Fangxing Fan, Xiao Dong, Xianghui Fang, Feng Xue, Fei Zheng and Jiang Zhu: Revisiting the relationship between the South Asian summer monsoon drought and El Ni？o warming pattern, Atmos. Sci. Let.18: 175–182 (2017), Published online in Wiley Online Library, (wileyonlinelibrary.com) DOI:10.1002/asl.740