• Momentum transport of wave zero during March: A possible predictor for the Indian summer monsoon

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    • Keywords


      Momentum transport; zonal waves; zone of westerlies; Indian monsoon rainfall.

    • Abstract


      Analysis of monthly momentum transport of zonal waves at 850 hPa for the period 1979 to 1993, between 30°S and 30°N for January to April, using zonal (𝑢) and meridional (𝜐) components of wind taken from the ECMWF reanalysis field, shows a positive correlation (.1% level of significance) between the Indian summer monsoon rainfall (June through September) and the momentum transport of wave zero TM(0) over latitudinal belt between 25°S and 5°N (LB) during March. Northward (Southward) TM(0) observed in March over LB subsequently leads to a good (drought) monsoon season over India which is found to be true even when the year is marked with the El- Nino event. Similarly a strong westerly zone in the Indian Ocean during March, indicates a good monsoon season for the country, even if the year is marked with El-Nino. The study thus suggests two predictors, TM(0) over LB and the strength of westerly zone in the Indian Ocean during March.

    • Author Affiliations


      S M Bawiskar1 V R Mujumdar1 S S Singh1

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

  • Journal of Earth System Science | News

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