Archive for the ‘Journal of Hydrometeorology’ Category

The 2010 Pakistan Flood and Russian Heat Wave: Teleconnection of Hydrometeorologic Extremes

September 3, 2011 Comments off

The 2010 Pakistan Flood and Russian Heat Wave: Teleconnection of Hydrometeorologic Extremes (PDF)
Source: Journal of Hydrometeorology

In this paper, we present preliminary results showing that the two record setting extreme events during 2010 summer, i.e., the Russian heat wave/wild fires and Pakistan flood were physically connected. We find that the Russian heat wave was associated with the development of an extraordinary strong and prolonged extratropical atmospheric blocking event, and excitation of a large-scale atmospheric Rossby wavetrain spanning western Russia, Kazakhstan, and northwestern China/Tibetan Plateau region. The southward penetration of upper level vorticity perturbations in the leading trough of the Rossby wave was instrumental in triggering anomalously heavy rain events over northern Pakistan and vicinity in mid-to-late July. Also shown are evidences that the Russian heat wave was amplified by a positive feedback through changes in surface energy fluxes between the atmospheric blocking pattern and an underlying extensive land region with below- normal soil moisture. The Pakistan heavy rain events were amplified and sustained by strong anomalous southeasterly flow along the Himalayas foothills and abundant moisture transport from the Bay of Bengal in connection with the northward propagation of the monsoonal intraseasonal oscillation.


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