Monsoon Prediction for Central Indian Region

Why in news?

A study by independent meteorologists has predicted a decline in rainfall over the Central Indian region.

What is the finding?

Low Pressure Systems (LPS) usually bring rain to this area.
But there is a declining trend in the number of these Low Pressure Systems (LPS).
The region will witness a 45% decline in the frequency of LPS activity.
About 50 years from now, the monsoon over central Indian region is expected to reduce.
This could result in lesser rainfall in this heavily rain-fed agrarian belt.
This is expected to be realised during the decades spanning between 2065 and 2095.
The study also highlights a 10% increase in the instances of LPS forming over land.
This would eventually lead to extreme rainfall over the North Indian plains.

How do LPSs work?

Low Pressure Systems (LPS) originate in the Bay of Bengal.
They travel landwards in a southeast-northwest direction.
It crosses Odisha, Andhra Pradesh, Telangana, Chhattisgarh, Jharkhand, Madhya Pradesh, Maharashtra and Uttar Pradesh.
This region is known as the core monsoon zone.
Most LPS pass by this region during the June to September monsoon season.
This makes it a very crucial region to understand the monsoon.
A new test-bed facility is being set up on the outskirts of Bhopal to study these key rain-bearing systems.

Why is the decline?

One of the main reasons for decrease in rainfall could be the large-scale decrease in the moist westerly winds.
These winds, called monsoon circulations, travel from the Arabian Sea along India’s west coast onto the mainland.
In addition, these are observed to have shifted northwards from their normal track during their forward propagation.
Climate change effect on the monsoon, especially over the core monsoon zone, is seen as inevitable.
With the rise in global temperature, the atmosphere would have a much higher moisture holding capacity.
But at a certain point this capacity would collapse, leading to extreme rainfall events and absence of consistent rainfall.
Extreme rainfall events are already found to be increasing in recent years.

Source: Indian Express