Agri Business

Monsoon logs a double-digit surplus as season concludes

Vinson Kurian Thiruvananthapuram | Updated on September 30, 2019 Published on September 30, 2019

Researchers and scientists not only here but even abroad have had a tough time predicting the whimsical course of the monsoon year after year.

A rare depression that developed early on Monday morning had moved 110 km north-west of Ahmedabad by the afternoon

The South-West monsoon has returned a surplus of 10 per cent on its last day, with a depression drenching Gujarat and a lesser endowed cyclonic circulation wiping out the rain deficit in Uttar Pradesh and Bihar.

That leaves only Haryana-Chandigarh-Delhi with any significant deficit (42 per cent), followed at some distance by West Uttar Pradesh (27 per cent); Nagaland-Manipur-Mizoram-Tripura (22 per cent); and the plains of Bengal (20 per cent).

Positive IOD role

The monsoon had a poor outing in June, and fared only slightly better in July but came back strongly in August and September, riding the twin advantage of a positive phase of the Indian Ocean Dipole (IOD) and a benign tropical Pacific.

The positive phase of the IOD sees the western basin of the Indian Ocean warm up relative to the East, which is beneficial for a concurrent monsoon. The Pacific was found to oblige by turning in only weak El Nino conditions.

The play of the positive IOD in the monsoon scheme of things was evident in the manner in which it swamped Central India even while North-West India and the South Peninsula went on to make considerable gains.

 

The latest rain driving feature over land is a rare depression that developed early on Monday morning and moved 110 km northwest of Ahmedabad (Gujarat) and 90 km southwest of Deesa (Gujarat) by the afternoon.

It should maintain the intensity of a depression for Monday night, continue to move East-North-East and weaken as a well-marked low-pressure area by Tuesday afternoon while pouring down its contents along the way. Slow-moving systems such as this — it does not really matter whether it is a conventional ‘low’ or has intensified twice over to become a depression — can drop sustained heavy rain under their footprint, creating flooding conditions.

The IMD has forecast fairly widespread to widespread rainfall with isolated heavy to very heavy and extremely heavy falls very likely over Saurashtra, Kutch, North Gujarat and South-East Rajasthan into Tuesday. Scattered to fairly widespread rainfall with isolated heavy falls has also been forecast over West Rajasthan during this period.

East India flooded

Towards the East, a cyclonic circulation in combination with a trough it was linked to, was principally responsible for setting massive floods over Bihar over the past three days. The circulation persisted over South-East Uttar Pradesh on Monday while the trough extended from a counterpart circulation over Punjab and ran further East-South-West to South Assam.

Published on September 30, 2019
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