Mr. Shahid Mehmood (PhD Candidate)

Computational Earth Sciences Group (CESG), Computational Sciences and Engineering Division (CSED), Oak Ridge National Laboratory, USA ;
Research Center for Environmental Changes (RCEC), Taiwan International Graduate Program (TIGP), Taiwan

Lagrangian based moisture back tracking algorithm is used toinvestigate the major oceanic and terrestrial regions that contribute moistureto winter precipitation, through winter westerly disturbance (WD), over HighAsian Mountains spanning Himalaya, Karakorum, Pamir and Tien Shen mountains;collectively called High Mountains of Asia (HMA) in this manuscript.Inter-annual variations in precipitation depends upon the WD activity, which isinfluenced by global atmospheric variability and tropical-extra-tropicalforcing known as teleconnection patterns. Few of these teleconnections havedirect influence on the HMA precipitation variability and we investigated thevariations in the moisture contribution from prime moisture suppliers duringthe positive and negative phases of few major teleconnections. Sometimes,different phases of the remote forcings are concurrently present, which canpotentially enhance or mute the impact of each other. We investigated thebehavior of each major moisture source by untangling remote teleconnectionsthrough Partial Correlation (PC) statistical technique and identified their individualcontribution to the HMA precipitation. Through PC, we found that the NorthAtlantic regions is negatively correlated to the precipitation during NorthAtlantic Oscillation (NAO), which is contrary to published literature.Although, the relationship between these modes of climate variability andprecipitation over HMA region is complex in nature but robust negativeprecipitation trend over the Karakoram region emphasizes the dire importance tounderstand the regional precipitation linkage with the teleconnections tominimize the uncertainty surrounding the Asian water towers in perspective tofuture climate change.