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Bay of Bengal Boundary Layer Experiment or BoBBLE

Topics Covered: Bilateral, regional and global groupings and agreements involving India and/or affecting India’s interests.

Bay of Bengal Boundary Layer Experiment or BoBBLE

What to study?

For Prelims: Key processes in BoB region, about BoBBLE.

For Mains: Significance of the experiment and how BoB affects monsoon.

Context: A team from Indian Institute of Science in Bengaluru and UK based University of East Anglia have created a blueprint for accurate prediction of monsoon, tropical cyclones and other weather-related forecast under the Bay of Bengal Boundary Layer Experiment or BoBBLE.


BoBBLE is a joint India-UK project.

It seeks to examine the impact of ocean processes in the Bay of Bengal (BoB) on the monsoon system.

It is is a project funded by Union Ministry of Earth Sciences and the Natural Environment Research Council of UK.

The Bay of Bengal (BoB) plays a fundamental role in controlling the weather systems that make up the South Asian summer monsoon system.

 Key processes in the southern BoB:

  • The saline Southwest Monsoon Current (SMC), a major control on the salt and SST distribution of the BoB, is shown to be controlled by both local (wind stress curl) and remote (equatorial wave propagation) factors, strongly linked to subseasonal variability over the wider Indian Ocean basin.
  • The high salinity core (HSC) of the SMC is shown to have its origins in the western equatorial Indian Ocean, reaching the BoB via the Somali Current, the Equatorial Undercurrent and the SMC.
  • Seasonal reversals that occur at the Somali Current and SMC junctions act as ‘railroad switches’ diverting water masses to different basins in the northern Indian Ocean.
  • Barrier layer formation and erosion in the southern BoB are found to be largely controlled by differential advection and resulting mixing driven by shear stress.
  • Chlorophyll in the southern BoB is strongly influenced by mixed layer processes and barrier layer strength.

 What are monsoons?

Monsoons are seasonal winds which reverse their direction with the change of season. The monsoon is a double system of seasonal winds. They flow from sea to land during the summer and from land to sea during winter.

  • Monsoons are peculiar to Indian Subcontinent, South East Asia, parts of Central Western Africa etc.
  • Indian Monsoons are Convection cells on a very large scale. They are periodic or secondary winds which seasonal reversal in wind direction.
  • Monsoons are also often associated with conditions like ‘El Nino’ (Spanish for ‘Little Boy’) that occurs every 2 to 7 years and La Nina.


Significance for India:

Monsoon is the lifeline of Indian economy as 2/3rd of it depends on farm income and rain is the only source of irrigation for over 40% of the country’s cropped area. Over 70% of India’s annual rainfall occurs in July-September monsoon season. A good monsoon increases crop productivity, raises farm income and drives the economy while, a weak monsoon inflates food prices and harms the economy.

Insta Links:

Prelims Link:

  1. Countries in BoB region.
  2. Objectives and members of BoBBLE.
  3. What is southwest monsoon?
  4. Factors affecting monsoon in Indian Ocean region.

Sources: AIR.