The Role of the Intertropical Discontinuity Region and the Heat Low in Dust Emission and Transport Over the Thar Desert, India: A Premonsoon Case Study

U. C. Dumka, D. G. Kaskaoutis, D. Francis, J. P. Chaboureau, A. Rashki, Suresh Tiwari, Sachchidanand Singh, E. Liakakou, N. Mihalopoulos

Research output: Contribution to journalArticlepeer-review

Abstract

A severe dust storm occurred over north India during 12–16 June 2018 is analyzed using satellite observations, reanalysis, ground-based measurements, and model (Meso-NH) simulations focusing on the dynamic processes that caused the dust-storm generation, uplift, and propagation as well as its impacts on air quality. The initial dust emission was triggered by strong near-surface southwesterlies (~15–20 m s−1) associated with the monsoon flow advancing northward, in response to the deepening of the thermal low over the Thar desert. The convergence between the northwesterlies and the monsoon flow along the Intertropical Discontinuity region caused high dust accumulation over northwest India in an area of weak winds. Convective mixing during daytime favors the vertical transport of dust to higher altitudes above the monsoon flow, but the towering Himalayas and the associated return northerly flow aloft play a blocking role leading to dust accumulation at heights between 1 and 3 km over northwest India. The prevailed northwesterlies in the middle troposphere favor the eastward transport of the dust plumes along the Ganges valley, helping to evacuate the dust toward east India. Based on Meso-NH model simulations, the dust storm was associated with dust loads higher than 30 gm−2 and AODs higher than 3, in agreement with MODIS observations. The impact of the dust storm on the spatial-temporal evolution of the PM10 and PM2.5 mass concentrations is studied using data from 23 air-quality stations over northern India, indicating daily PM10 peaks reaching at ~900 μg m−3, implying a severe degradation of air quality.

Original languageEnglish (US)
Pages (from-to)13197-13219
Number of pages23
JournalJournal of Geophysical Research: Atmospheres
Volume124
Issue number23
DOIs
StatePublished - Dec 16 2019

Keywords

  • Meso-NH model
  • Thar desert
  • dust storm
  • intertropical front
  • monsoon flow
  • thermal low

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

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