Mechanisms for projected future changes in south Asian monsoon precipitation

Meehl, G. A.; Arblaster, J. M.
December 2003
Climate Dynamics;Dec2003, Vol. 21 Issue 7/8, p659
Academic Journal
Results are first presented from an analysis of a global coupled climate model regarding changes in future mean and variability of south Asian monsoon precipitation due to increased atmospheric CO2 for doubled (2 × CO2) and quadrupled (4 × CO2) present-day amounts. Results from the coupled model show that, in agreement with previous studies, mean area-averaged south Asian monsoon precipitation increases with greater CO2 concentrations, as does the interannual variability. Mechanisms producing these changes are then examined in a series of AMIP2-style sensitivity experiments using the atmospheric model (taken from the coupled model) run with specified SSTs. Three sets of ensemble experiments are run with SST anomalies superimposed on the AMIP2 SSTs from 1979–97: (1) anomalously warm Indian Ocean SSTs, (2) anomalously warm Pacific Ocean SSTs, and (3) anomalously warm Indian and Pacific Ocean SSTs. Results from these experiments show that the greater mean monsoon precipitation is due to increased moisture source from the warmer Indian Ocean. Increased south Asian monsoon interannual variability is primarily due to warmer Pacific Ocean SSTs with enhanced evaporation variability, with the warmer Indian Ocean SSTs a contributing but secondary factor. That is, for a given interannual tropical Pacific SST fluctuation with warmer mean SSTs in the future climate, there is enhanced evaporation and precipitation variability that is communicated via the Walker Circulation in the atmosphere to the south Asian monsoon to increase interannual precipitation variability there. This enhanced monsoon variability occurs even with no change in interannual SST variability in the tropical Pacific.


Related Articles

  • Real-time performance of a multi-model ensemble-based extended range forecast system in predicting the 2014 monsoon season based on NCEP-CFSv2. Sahai, A. K.; Chattopadhyay, R.; Joseph, S.; Mandal, R.; Dey, A.; Abhilash, S.; Krishna, R. P. M.; Borah, N. // Current Science (00113891);11/25/2015, Vol. 109 Issue 10, p1802 

    The real-time validation of any strategy to forecast the Indian summer monsoon rainfall requires comprehensive assessment of performance of the model on subseasonal scale. The CFSv2-based grand multi-model ensemble (CGMME) approach based on the NCEPCFS version 2 models, as developed and reported...

  • Characteristics of an African Easterly Wave Observed during NAMMA. Cifelli, Robert; Lang, Timothy; Rutledge, Steven A.; Guy, Nick; Zipser, Edward J.; Zawislak, Jon; Holzworth, Robert // Journal of the Atmospheric Sciences;Jan2010, Vol. 67 Issue 1, p3 

    The evolution of an African easterly wave is described using ground-based radar and ancillary datasets from three locations in West Africa: Niamey, Niger (continental), Dakar, Senegal (coastal), and Praia, Republic of Cape Verde (oceanic). The data were collected during the combined African...

  • Reproducibility and predictability of the Asian summer monsoon in the ECHAM4-GCM. Cherchi, A.; Navarra, A. // Climate Dynamics;Feb2003, Vol. 20 Issue 4, p365 

    The mean evolution of the Asian summer monsoon and its interannual variability have been studied using three simulations (from 1961 to 1994) with the ECHAM4 General Circulation Model (GCM). The results have been compared with observational data and with two reanalyses data sets: the ECMWF...

  • Heavy Precipitation Over the US: Has it Increased as Some have Predicted it Should?  // CO2 Science;8/29/2012, Vol. 15 Issue 35, p4 

    The article discusses a study which determined whether there has been a systematic change in the extreme events of precipitation. Trends of monthly precipitation were assessed for statistical significance in observations and Global Climate Model (GCM) simulations over the U.S. The study found...

  • Meteorological Effects on the Evolution of High Ozone Episodes in the Greater Seoul Area. Young Sung Ghim; Hyun Sun Oh; Young-Soo Chang, Janusz // Journal of the Air & Waste Management Association (Air & Waste M;Feb2001, Vol. 51 Issue 2, p185 

    Three high O3 episodes--7 days in 1992 (July 3-July 9), 9 days in 1994 (July 21-July 29), and another 3 days in 1994 (August 22-August 24)--were selected on the basis of morning (7:00 a.m.-10:00 a.m.) average wind direction and speed and daily maximum O3 concentrations in the greater Seoul,...

  • Mountain Torque Events at the Tibetan Plateau. Egger, Joseph; Hoinka, Klaus-Peter // Monthly Weather Review;Feb2008, Vol. 136 Issue 2, p389 

    The interaction of large-scale wave systems with the Tibetan Plateau (TP) is investigated by regressing pressure, potential temperature, winds, precipitation, and selected fluxes in winter onto the three components Toi of this massif’s mountain torque on the basis of the 40-yr ECMWF...

  • Interactive comment on "Strong summer monsoon during the cool MIS-13" by Q. Z. Yin and Z. T. Guo. Vandenberghe, J. // Climate of the Past Discussions;2007 Supplement, Vol. 3, pS683 

    The author comments on the article "Strong Summer Monsoon During the Cool MIS-13," by Q. Z. Yin and Z. T. Guo. A discrepancy between alternating warm and cold periods was mentioned in the introduction. The period prior to the mid-Brunhes event exhibited a weaker amplitude of ice volume...

  • Monitoring the Monsoon in the Himalayas: Observations in Central Nepal, June 2001. Barros, Ana P.; Lang, Timothy J. // Monthly Weather Review;Jul2003, Vol. 131 Issue 7, p1408 

    The Monsoon Himalayan Precipitation Experiment (MOHPREX) occurred during June 2001 along the south slopes of the Himalayas in central Nepal. Radiosondes were launched around the clock from two sites, one in the Marsyandi River basin on the eastern footslopes of the Annapurna range, and one...

  • Rainfall Types in the West African Sudanian Zone during the Summer Monsoon 2002. Fink, A. H.; Vincent, D. G.; Ermert, V. // Monthly Weather Review;Aug2006, Vol. 134 Issue 8, p2143 

    Enhanced surface and upper-air observations from the field campaign of the Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa (IMPETUS) project are used to partition rainfall amounts over the West African Sudanian zone during the 2002 summer monsoon season...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics