Pakistan's two-stage monsoon and links with the recent climate change

Shih Yu Wang, Robert E. Davies, Wan Ru Huang, Robert R. Gillies

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Meteorological conditions related to the Pakistan floods of 2010 were examined in the context of monsoon dynamics and large-scale circulations. Case and climatological analyses suggest that summer precipitation in northern Pakistan comprises two distinct phases: (1) a premonsoon trough phase (July) whose rainfall is more episodic and intense, occurring prior to arrival of the monsoon trough, and (2) a monsoon trough phase (August) whose rainfall is persistent, yet less episodic, driven by northward migration of the monsoon trough. Analyses of conditional instability, moisture flux, and circulation features support a persistent increase in conditional instability during the July premonsoon trough phase, accompanied by increased frequency of heavy rainfall events. Conversely, evidence does not support intensification of the August monsoon trough phase. The increased convective activity during the premonsoon trough phase agrees with the projected increase in the intensity of heavy rainfall events over northern Pakistan. Large-scale circulation analysis reveals an upper-level cyclonic anomaly over and to the west of Pakistan-a feature empirically associated with weak monsoon. The analysis also suggests that the anomalous circulation in 2010 is not sporadic but rather is part of a long-term trend that defies the typical linkage of strong monsoons with an anomalous anticyclone in the upper troposphere.

Original languageEnglish
Article numberD16114
JournalJournal of Geophysical Research Atmospheres
Volume116
Issue number16
DOIs
Publication statusPublished - 2011 Jan 1

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Pakistan
monsoons
climate change
troughs
Climate change
Rain
trough
monsoon
rain
rainfall
Troposphere
Moisture
anticyclones
Fluxes
moisture flux
anticyclone
troposphere
summer
linkages
moisture

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Pakistan's two-stage monsoon and links with the recent climate change. / Wang, Shih Yu; Davies, Robert E.; Huang, Wan Ru; Gillies, Robert R.

In: Journal of Geophysical Research Atmospheres, Vol. 116, No. 16, D16114, 01.01.2011.

Research output: Contribution to journalArticle

Wang, Shih Yu ; Davies, Robert E. ; Huang, Wan Ru ; Gillies, Robert R. / Pakistan's two-stage monsoon and links with the recent climate change. In: Journal of Geophysical Research Atmospheres. 2011 ; Vol. 116, No. 16.
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