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Title: Dominating Controls for Wetter South Asian Summer Monsoon in the Twenty-First Century

This study analyzes a suite of global climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) archives to understand the mechanisms behind a net increase in the South Asian summer monsoon precipitation in response to enhanced radiative forcing during the twenty-first century. An increase in radiative forcing fuels an increase in the atmospheric moisture content through warmer temperatures, which overwhelms the weakening of monsoon circulation and results in an increase of moisture convergence and therefore summer monsoon precipitation over South Asia. Moisture source analysis suggests that both regional (local recycling, the Arabian Sea, the Bay of Bengal) and remote (including the south Indian Ocean) sources contribute to the moisture supply for precipitation over South Asia during the summer season that is facilitated by the monsoon dynamics. For regional moisture sources, the effect of excessive atmospheric moisture is offset by weaker monsoon circulation and uncertainty in the response of the evapotranspiration over land, so anomalies in their contribution to the total moisture supply are either mixed or muted. In contrast, weakening of the monsoon dynamics has less influence on the moisture supply from remote sources that not only is a dominant moisture contributor in the historical period butmore » is also the net driver of the positive summer monsoon precipitation response in the twenty-first century. Finally, the results also indicate that historic measures of the monsoon dynamics may not be well suited to predict the nonstationary moisture-driven South Asian summer monsoon precipitation response in the twenty-first century.« less
 [1] ;  [1] ;  [1] ;  [2] ;  [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division. Climate Change Science Inst.
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Atmospheric Sciences and Global Change Division
  3. Univ. of Arizona, Tucson, AZ (United States). Dept. of Atmospheric Sciences
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC05-00OR22725; AC05-76RL01830
Accepted Manuscript
Journal Name:
Journal of Climate
Additional Journal Information:
Journal Volume: 28; Journal Issue: 8; Journal ID: ISSN 0894-8755
American Meteorological Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES climate models; climate variability