Anatomy of Indian heatwaves

Ratnam, J. V., Behera, Swadhin K., Ratna, Satyaban B., Rajeevan, M. and Yamagata, Toshio (2016) Anatomy of Indian heatwaves. Scientific Reports, 6. ISSN 2045-2322

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    Abstract

    India suffers from major heatwaves during March-June. The rising trend of number of intense heatwaves in recent decades has been vaguely attributed to global warming. Since the heat waves have a serious effect on human mortality, root causes of these heatwaves need to be clarified. Based on the observed patterns and statistical analyses of the maximum temperature variability, we identified two types of heatwaves. The first-type of heatwave over the north-central India is found to be associated with blocking over the North Atlantic. The blocking over North Atlantic results in a cyclonic anomaly west of North Africa at upper levels. The stretching of vorticity generates a Rossby wave source of anomalous Rossby waves near the entrance of the African Jet. The resulting quasi-stationary Rossby wave-train along the Jet has a positive phase over Indian subcontinent causing anomalous sinking motion and thereby heatwave conditions over India. On the other hand, the second-type of heatwave over the coastal eastern India is found to be due to the anomalous Matsuno-Gill response to the anomalous cooling in the Pacific. The Matsuno-Gill response is such that it generates northwesterly anomalies over the landmass reducing the land-sea breeze, resulting in heatwaves.

    Item Type: Article
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    Related URLs:
    Depositing User: Pure Connector
    Date Deposited: 04 May 2017 06:11
    Last Modified: 16 Aug 2018 00:52
    URI: https://ueaeprints.uea.ac.uk/id/eprint/63389
    DOI: 10.1038/srep24395

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