Summer rainfall India: A review of monsoonal and extramonsoonal aspects ‐ II

Chakravarti, A. K.

doi:10.1080/00046973.1968.9676553

Cited by 6 publications

(3 citation statements)

References 2 publications

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“…Chakravarti [, ] advanced two important insights related to synoptic characteristics of the WDs. First, he stipulated the governing role of the Indian Himalayas in WD dynamics, and second, he noted that WDs that lead to precipitation are initially generated and travel in upper atmospheric flow patterns.…”

Section: Wds: Synoptic Scalementioning

confidence: 99%

“…Further characterization of WDs by Datta and Gupta [1967] indicated that they move at a speed of 8 to 10°longitude per day (e.g., 10-12 m s À1 ) except during the formation and dissipation stages when the movement is comparatively slow with a life-cycle duration of 3-4 days. Chakravarti [1968aChakravarti [ , 1968b advanced two important insights related to synoptic characteristics of the WDs. First, he stipulated the governing role of the Indian Himalayas in WD dynamics, and second, he noted that WDs that lead to precipitation are initially generated and travel in upper atmospheric flow patterns.…”

Section: Wds: Synoptic Scalementioning

confidence: 99%

See 1 more Smart Citation

Western Disturbances: A review

Dimri

Niyogi

Barros

et al. 2015

Reviews of Geophysics

354

216

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Cyclonic storms associated with the midlatitude Subtropical Westerly Jet (SWJ), referred to as Western Disturbances (WDs), play a critical role in the meteorology of the Indian subcontinent. WDs embedded in the southward propagating SWJ produce extreme precipitation over northern India and are further enhanced over the Himalayas due to orographic land-atmosphere interactions. During December, January, and February, WD snowfall is the dominant precipitation input to establish and sustain regional snowpack, replenishing regional water resources. Spring melt is the major source of runoff to northern Indian rivers and can be linked to important hydrologic processes from aquifer recharge to flashfloods. Understanding the dynamical structure, evolution-decay, and interaction of WDs with the Himalayas is therefore necessary to improve knowledge which has wide ranging socioeconomic implications beyond short-term disaster response including cold season agricultural activities, management of water resources, and development of vulnerability-adaptive measures. In addition, WD wintertime precipitation provides critical mass input to existing glaciers and modulates the albedo characteristics of the Himalayas and Tibetan Plateau, affecting large-scale circulation and the onset of the succeeding Indian Summer Monsoon. Assessing the impacts of climate variability and change on the Indian subcontinent requires fundamental understanding of the dynamics of WDs. In particular, projected changes in the structure of the SWJ will influence evolution-decay processes of the WDs and impact Himalayan regional water availability. This review synthesizes past research on WDs with a perspective to provide a comprehensive assessment of the state of knowledge to assist both researchers and policymakers, and context for future research.

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Section: Wds: Synoptic Scalementioning

confidence: 99%

Section: Wds: Synoptic Scalementioning

confidence: 99%

Western Disturbances: A review

Dimri

Niyogi

Barros

et al. 2015

Reviews of Geophysics

354

216

View full text Add to dashboard Cite

show abstract

“…The TD tracking algorithm does not make this distinction, so these events-five in all satisfying our remaining criteria-were removed. Several studies have highlighted the importance of these WD-born TDs (Pisharoty and Desai 1956;Chakravarti 1968;Loe et al 2005), but to what extent they are genuinely ''tropical'' remains an open question.…”

Section: Discussionmentioning

confidence: 99%

How interactions between tropical depressions and western disturbances affect heavy precipitation in South Asia

Hunt

Turner

Schiemann

2021

Monthly Weather Review

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Interactions over South Asia between tropical depressions (TDs) and extratropical storms known as western disturbances (WDs) are known to cause extreme precipitation events, including those responsible for the 2013 floods over northern India. In this study, existing databases of WD and TD tracks are used to identify potential WD–TD interactions from 1979–2015; these are filtered according to proximity and intensity, leaving 59 cases which form the basis of this paper. Synoptic charts, vorticity budgets, and moisture trajectory analyses are employed to identify and elucidate common interaction types among these cases. Two broad families of interaction emerge. Firstly, a dynamical coupling of the WD and TD, whereby either the upper- and lower-level vortices superpose (a vortex merger), or the TD is intensified as it passes into the entrance region of a jet streak associated with the WD (a jet-streak excitation). Secondly, a moisture exchange between the WD and TD, whereby either anomalous moisture is advected from the TD to the WD, resulting in anomalous precipitation near the WD (a TD-to-WD moisture exchange), or anomalous moisture is advected from the WD to the TD (a WD-to-TD moisture exchange). Interactions are most common in the post-monsoon period as the subtropical jet, which brings WDs to the subcontinent, returns south; there is a smaller peak in May and June, driven by monsoon onset vortices. Precipitation is heaviest in dynamically-coupled interactions, particularly jet-streak excitations. Criteria for automated identification of interaction types are proposed, and schematics for each type are presented to highlight key mechanisms.

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Western Disturbances – Structure

Dimri

Chevuturi

2016

Western Disturbances - An Indian Meteorological Perspective

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Summer rainfall India: A review of monsoonal and extramonsoonal aspects ‐ II

Cited by 6 publications

References 2 publications

Western Disturbances: A review

Western Disturbances: A review

How interactions between tropical depressions and western disturbances affect heavy precipitation in South Asia

Western Disturbances – Structure

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