• Elucidating intra-seasonal characteristics of Indian summer monsoon. Part-I: Viewed from remote sensing observations, reanalysis and model datasets

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    • Keywords


      Intra-seasonal phases of the monsoon; structure of the monsoon; kinematic and dynamical features of the monsoon phases

    • Abstract


      In this study, we examine the transitions in the monsoon phases (onset, active, break and the withdrawal) during an entire monsoon season. This makes use of a host of observational tools that come from GPM (Global Precipitation Measurement) and TRMM (Tropical Rainfall Measuring Mission) satellites for precipitation estimates, the vertical structure of rain, hydrometeors and cloud types from TRMM and CloudSat datasets. During onset, the mean moisture convergence, especially over west and south-west coast of India is $2 \times 10^{-4} \rm{kg m^{-1} s^{-1}}$; however, it carries much higher value of >$4 \times 10^{-4 }\rm{kg m^{-1} s^{-1}}$ during the active phase over central eastern India. Much lesser moisture convergence (<$1 \times 10^{-4} \rm{kg m^{-1} s^{-1}}$) is noted over Western Ghats area during the break phase. However, there are northeasterly moisture fluxes present over southern part of India during withdrawal phase. The tall cumulonimbus clouds that extend out to 16 km are illustrate during onset, the active phase is dominated by alto stratus and nimbostratus type clouds that are somewhat shallower. In general, we noted an absence of such clouds during the break and the withdrawal phases. Those structures were consistent in a number of derived fields such as the moisture convergence, moisture fluxes, the energy conversions between the rotational and the divergent kinetic energy and the corresponding phases of the intra-seasonal oscillations.

    • Author Affiliations



      1. Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL 32306, USA.
      2. RMSI Pvt. Ltd., A-8, Sector-16, Noida, Uttar Pradesh 201301, India.
      3. Department of Environmental Engineering, Texas A&M University, Kingsville, TX 78363, USA.
    • Dates

  • Journal of Earth System Science | News

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