Climatology of the premonsoon Indian dryline

  • Nasreen Akter, Kazuhisa Tsuboki
  • International Journal of Climatology, December 2016, Wiley
  • DOI: 10.1002/joc.4968

Premonsoon Dryline

What is it about?

The dryline with intense dew point gradient of 1°C/10 km along the east coast of India in premonsoon season is differing from the classical dryline. Deep, hot, dry air and warm, shallow, moist air forms an inclined moisture gradient from the east at a level of approximately 700 hPa over the Bay of Bengal to the west at the surface of the eastern coast of India. During the entire premonsoon season, surface dryline exhibits diurnal oscillatory motion in the zonal direction with an average displacement of 100 km, and the eastward movement is almost three times faster than the westward movement.

Why is it important?

The Indian dryline is directly responsible for the formation of severe thunderstorms in the premonsoon. Many other atmospheric events i.e. formation of tropical cyclone and monsoon onset are also influenced by the premonsoon dryline. Therefore, it is essential to understand the dryline position, its longevity, and along-dryline variability.


DR Nasreen Akter
Bangladesh University of Engineering and Technology

During the premonsoon, dryline causes severe local convective storms (Nor’wester) and tornadoes in the northeastern Indian subcontinent including Bangladesh which results a massive property damage and a large number of injuries and deaths each year. This study will provide sustainable assistants in taking plan, action and step towards disaster managements and will save millions of lives.

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The following have contributed to this page: DR Nasreen Akter