• Seasonal prediction of summer monsoon rainfall over cluster regions of India

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    • Keywords


      SNN cluster; effective strength index; rainfall clusters over India.

    • Abstract


      Shared nearest neighbour (SNN) cluster algorithm has been applied to seasonal (June–September) rainfall departures over 30 sub-divisions of India to identify the contiguous homogeneous cluster regions over India. Five cluster regions are identified. Rainfall departure series for these cluster regions are prepared by area weighted average rainfall departures over respective sub-divisions in each cluster. The interannual and decadal variability in rainfall departures over five cluster regions is discussed. In order to consider the combined effect of North Atlantic Oscillation (NAO) and Southern Oscillation (SO), an index called effective strength index (ESI) has been defined. It has been observed that the circulation is drastically different in positive and negative phases of ESI-tendency from January to April. Hence, for each phaseof ESI-tendency (positive and negative), separate prediction models have been developed for predicting summer monsoon rainfall over identified clusters. The performance of these models have been tested and found to be encouraging.

    • Author Affiliations


      S B Kakade1 Ashwini Kulkarni1

      1. Indian Institute of Tropical Meteorology, Pune 411 008, India.
    • Dates

  • Journal of Earth System Science | News

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      Posted on July 25, 2019

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