‘Urban heat island effect’ triggering heavy rains in Hyd

Hyderabad: The continuous expansion of Hyderabad in terms of area together with pollution caused by lakhs of vehicles are leading to the ‘urban heat island effect’, which consequently is triggering heavy rains in the city. The heat has a magnetic drawing effect on moisture from neighbouring districts. This is one of the main reasons that the city is witnessing heavy rains late in the evenings this monsoon.

The city has received an excess rainfall of 27 per cent during this monsoon starting from June 1. What is baffling the citizens is that heavy rains are lashing the city in the evenings and are concentrated more in the city’s core areas and not the adjoining districts.

The IMD officials have come up with the reasons for such a phenomenon.

Senior meteorologist in IMD, GNRS Srinivas Rao told The Hans India that skyscrapers and expansion that stretches up to 30 to 40 sq. km are generating massive heat.

“As per our forecast and analysis, it should have rained even in Vikarabad, Sangareddy, Meak, Mahabubnagar and Yadadri.

However, what is happening every evening is that moisture is coming into the city from the districts due to which we are noticing huge development of cumulonimbus clouds. In scientific parlance, this is called the ‘urban heat island effect’,” he said.

Lakhs of vehicles, extensive use of air-conditioners and pollution caused by industries are increasing the city’s temperature by four to five degrees compared to the neighbouring districts. We witnessed a phenomenon of high temperature all over the state compared to the previous monsoon season, he added.

The IMD official said that the lower stratum of air is harder than the upper air. The colder, denser air is heavier and tends to sink, while warmer and the less dense air is lighter and creates lower pressure. The denser air pushes the colder and starts to move up thereby forming a low relative pressure. “Initially scattered cumulonimbus clouds were developed in the outskirts.

Later they transformed into clouds leading to unexpected heavy rains. This is a phenomenon that we have observed this year,” said Srinivas Rao.

The city on Monday experienced intense rainfall, with some areas like Banjara Hills recording 103.8 mm, while Srinagar Colony and Khairatabad received 97.8 mm and 87.8 mm, respectively.