Impact of the Atlantic Multidecadal Oscillation on the Asian summer monsoon

Abstract

[1] The impact of the Atlantic Multidecadal Oscillation (AMO) on the Asian summer monsoon is investigated using a coupled atmosphere-ocean global general circulation model by imposing the AMO-associated sea surface temperature anomalies in the Atlantic as boundary forcing, and allowing atmosphere-ocean interactions outside the Atlantic. The positive AMO phase, characterized by anomalous warm North Atlantic and cold South Atlantic, leads to strong Southeast and east Asian summer monsoons, and late withdrawal of the Indian summer monsoon. These changes of monsoons are mainly through coupled atmosphere-ocean feedbacks in the western Pacific and Indian Oceans and tropospheric temperature changes over Eurasia in response to the imposed forcing in the Atlantic. The results are in agreement with the observed climate changes in China corresponded to the AMO phases. They suggest a non-local mechanism for the Asian summer monsoon variability and provide an alternative view to understanding its interdecadal variation during the twentieth century.

Decadal to multi-decadal scale variability of Indian summer monsoon rainfall in the coupled ocean-atmosphere-chemistry climate model SOCOL-MPIOM

“…All these studies indicate inconsistent results over Indian region. Lu et al (2006) found enhancement of precipitation over the Southeast Asia (Myanmar) in Hadley Centre Coupled Model version 3 (HadCM3) which is consistent with the four model simulations of this study for southern part of Myanmar. They found that the warm phase of AMO causes positive SST anomalies over the eastern Indian Ocean and Maritime continent.…”

“…They attributed this warming to the limitation in the observational data owing to dearth of long instrumental records. Other climate models also show a similar kind of warming over the Indian Ocean (see, Lu et al 2006;Msadek et al 2011).…”

“…Using Bergen Climate Model (BCM) Luo et al (2011) found enhanced rainfall over central India and Indian Peninsula; however, they identified an opposite pattern over north India for JJA over the time period 1850-1999. Some other studies based on climate models by Sutton and Hodson (2007), Knight et al (2006), and Lu et al (2006) showed increased rainfall over north India but reduced rainfall over central India during positive phase of AMO. All these studies indicate inconsistent results over Indian region.…”

“…Whether the AMO is caused by internal processes or related to external forcings is currently under discussion (see, Otterå et al 2010;Booth et al 2012;Zhang et al 2013). The observational, paleoclimate, and simulated datasets show increased (decreased) ISMR during positive (negative) phase of the AMO (see, Gupta et al 2003;Zhang and Delworth 2006;Goswami et al 2006b;Lu et al 2006;Feng and Hu 2008;Li et al 2008;Wang et al 2009;Msadek and Frankignoul 2009;Joshi and Pandey 2011;Joshi and Rai 2015;Luo et al 2011;Krishnamurthy 2014, 2015). In contrast to the AMO, the PDO, the leading mode of SSTs in the North Pacific Ocean with periodicities of 15-25 years and 50-70 years (e.g., Mantua and Hare 2002), is suggested having an opposite effect on ISMR (see, Krishnan et al 2003;Roy et al 2003;Krishnamurthy and Krishnamurthy 2013).…”

Solar Arctic-Mediated Climate Variation on Multidecadal to Centennial Timescales: Empirical Evidence, Mechanistic Explanation, and Testable Consequences

“…Several important and related consequences and connections of multidecadalto centennial-scale variations of the Atlantic MOC/THC have recently been pointed out by Dong et al (2006), Goswami et al (2006), Knight et al (2006), Lu et al (2006), Li and Bates (2007), Sutton and Hodson (2007), Timmermann et al (2007), Chang et al (2008), Denton and Broecker (2008), Feng and Hu (2008), Li et al (2008), Ting et al (2008), and Wang et al (2009).…”