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Dynamics of Indian summer monsoon in different phases

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Abstract

Better understanding on the phases of Indian summer monsoon i.e., onset, progress and withdrawal helps in the decision making and proper management. In this paper, date of onset of monsoon (DOM) and date of withdrawal of monsoon (DWM) is estimated using the long-term daily rainfall data observed by the India Meteorological Department (IMD) and cumulative rainfall anomaly concept, as the onset/withdrawal represents a signature of rainfall transition. The results are promising with a better match between the estimated DOM and IMD announced DOM over Kerala. The length of monsoon season variability is also analysed. The concept of onset at grid point (OGP) in India is also evaluated and progress of monsoon is monitored by considering the latitudinal variation, persistent & strength of rainfall in the continental India. The zonal classification of the spread of monsoon in terms of the intensity and time (duration) is presented. Zone wise pentad analysis of onset clearly signifies the progress of monsoon and its dependency on various physical factors like SST, OLR, TTG, ITCZ, Energy budget and wind circulation. The impact of ENSO on the OGP is brought out, which clearly shows that DOM, DWM and progress is almost influenced by the largescale processes. The intensity–duration–frequency analysis quantified the actual ISM length, seasonal rainfall and rainy days at all locations in India. This study will help modellers in better understanding of onset and progress of monsoon dynamics in India and can be integrated with NWP for the accurate and advance prediction of DOM and the progress.

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Acknowledgements

The author SL acknowledges CSIR and RD acknowledges UGC for the fellowships. The authors are thankful to Nikhilauma P for computational help.

Funding

The work is funded by a project under National Mission on Himalayan Studies (NMHS) of Ministry of Environment, forest and climate change (MoEFCC), Govt. of India for the project funding support (grant no: GBPNI/NMHS-2019-20/MG/315). The funds received under ICPS mission project of Department of Science and Technology, Govt. of India also used in this study.

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Authors and Affiliations

  1. CSIR Fourth Paradigm Institute, Wind Tunnel Road, 37, Bangalore, India

    Smrutishree Lenka, Krushna Chandra Gouda & Rani Devi

  2. Department of Physics, Dayananda Sagar College of Engineering, Bangalore, India

    Smrutishree Lenka & C. M. Joseph

  3. Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India

    Krushna Chandra Gouda & Rani Devi

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  1. Smrutishree Lenka
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Conceptualization: KCG and SL; analysis and investigation: SL, KCG and RD; writing-original draft preparation: SL, KCG, RD and JCM; Supervision: KCG.

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Correspondence to Krushna Chandra Gouda.

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Lenka, S., Gouda, K.C., Devi, R. et al. Dynamics of Indian summer monsoon in different phases. Clim Dyn 62, 473–495 (2024). https://doi.org/10.1007/s00382-023-06925-1

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