Probability distribution analysis of extreme rainfall events in a flood-prone region of Mumbai, India

Parchure, Amit Sharad; Gedam, Shirish S.

doi:10.1007/s12517-019-4473-2

Cited by 9 publications

(1 citation statement)

References 54 publications

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“…The west coast of India receives more monsoonal rainfall than any part of monsoonal South Asia except Meghalaya, averaging about three times as much as the rest of the region (Krishnamurthy and Shukla, 2000; Rajeevan et al ., 2006). As a result, this region is prone to periods of extremely heavy rainfall (e.g., Venkatesh and Jose, 2007; Deb et al ., 2008; Tawde and Singh, 2015; Mishra and Shah, 2018; Hunt and Menon, 2019; Lakshmi et al ., 2019; Parchure and Gedam, 2019), which are exaggerated in scale and impact by the presence of the Western Ghats (WGs)—a thin mountain range near the coast, orientated almost perpendicular to the monsoon westerlies. There is thus a pressing need to explore the modes and timescales of variability that drive this rainfall, the understanding of which will improve its predictability.…”

Section: Introductionmentioning

confidence: 99%

Modes of coastal precipitation over southwest India and their relationship with intraseasonal variability

Hunt

Turner

Stein

et al. 2020

Quart J Royal Meteoro Soc

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The west coast of India, dominated by the Western Ghats mountain range, is among the rainiest places in the Tropics. The interaction between the land-sea contrast of the coast, the monsoonal westerlies, and the oblique mountains is subject to complex intraseasonal variability, which has not previously been explored in depth. This study investigates that variability from the perspective of the land-sea contrast, using empirical orthogonal function analysis to discern regimes of onshore and offshore rainfall over southwest India and the eastern Indian Ocean. Locally, it is found that the rainfall is most sensitive to midtropospheric humidity: when this is anomalously high, deep convection is encouraged; when this is anomalously low, it is suppressed. A moisture-tracking algorithm is employed to determine the primary sources of the anomalously wet and dry midtropospheric air. There are important secondary contributions from low-level vorticity and cross-shore moisture flux. The dominant control on intraseasonal variability in coastal precipitation is found to be the Boreal Summer Intraseasonal Oscillation (BSISO): over 75% of the strongest offshore events occur during phases 3 and 4; and about 40% of the strongest onshore events occur during phases 5 and 6. The location of monsoon low-pressure systems is also shown to be important in determining the magnitude and location of coastal rainfall.

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