Will the South Asian monsoon overturning circulation stabilize any further?

Krishnan, R. ; Sabin, T. P. ; Ayantika, D. C. ; Kitoh, A. ; Sugi, M. ; Murakami, H. ; Turner, A. G. ; Slingo, J. M. ; Rajendran, K. (2013) Will the South Asian monsoon overturning circulation stabilize any further? Climate Dynamics, 40 (1-2). pp. 187-211. ISSN 0930-7575

Full text not available from this repository.

Official URL: https://link.springer.com/article/10.1007/s00382-0...

Related URL: http://dx.doi.org/10.1007/s00382-012-1317-0

Abstract

Understanding the response of the South Asian monsoon (SAM) system to global climate change is an interesting scientific problem that has enormous implications from the societal viewpoint. While the CMIP3projections of future changes in monsoon precipitation used in the IPCC AR4show major uncertainties, there is a growing recognition that the rapid increase of moisture in a warming climate can potentially enhance the stability of the large-scale tropical circulations. In this work, the authors have examined the stability of the SAM circulation based on diagnostic analysis of climate datasets over the past half century; and addressed the issue of likely future changes in the SAM in response to global warming using simulations from an ultra-high resolution (20 km) global climate model. Additional sensitivity experiments using a simplified atmospheric model have been presented to supplement the overall findings. The results here suggest that the intensity of the boreal summer monsoon overturning circulation and the associated southwesterly monsoon flow have significantly weakened during the past 50-years. The weakening trend of the monsoon circulation is further corroborated by a significant decrease in the frequency of moderate-to-heavy monsoon rainfall days and upward vertical velocities particularly over the narrow mountain ranges of the Western Ghats. Based on simulations from the 20-km ultra high-resolution model, it is argued that a stabilization (weakening) of the summer monsoon Hadley-type circulation in response to global warming can potentially lead to a weakened large-scale monsoon flow thereby resulting in weaker vertical velocities and reduced orographic precipitation over the narrow Western Ghat mountains by the end of the twenty-first century. Supplementary experiments using a simplified atmospheric model indicate a high sensitivity of the large-scale monsoon circulation to atmospheric stability in comparison with the effects of condensational heating.

Item Type:Article
Source:Copyright of this article belongs to Springer Verlag.
Keywords:South Asian Monsoon; Global Climate Change; Stability of Monsoon Circulation; Orographic Precipitation Response; Western Ghats
ID Code:109356
Deposited On:01 Feb 2018 10:15
Last Modified:01 Feb 2018 10:15

Repository Staff Only: item control page