RISE IN RAINFALL, Temperature change is a common phenomenon we’re acquainted with. Over the last few years, a distinct change could be observed in the weather. Especially in Kerala, Tamil Nadu and Telangana, a considerable rise in precipitation during monsoon seasons have been recorded between 2000 and 2017.
These particular states differ in their rainfall patterns.
Kerala experiences a humid tropical wet climate during Southwest monsoons from June to October. Kerala is a situated tropical region on the South Western coast of India, off the Arabian Sea.
Tamil Nadu receives rainfall during winter due to Northeast trade winds covering months of October to December. It’s along the coast of the Bay of Bengal.
Telangana has the longest season of summer and it also receives rain due to Southwest winds from June to September.
Recently a study was taken up by Centre for Earth, Ocean, and Atmospheric Sciences of the University of Hyderabad. The study led by Dr. Karumuri Ashok mainly focused on the reason behind the increase in rainfall in the southern states of India in the past few years. They owe the reason behind the rise in rainfall by 20-25% to the growth in urbanization in these areas.
Due to the very different location and reasons for rainfall, it was difficult to pinpoint one cause behind the rise in rainfall.
The change in Land Use Land Cover in all three states is the only factor in common. The whole research team including the Ph.D. student Boyaj not only gathered LULC data from ISRO (Indian Space Research Organization) but also carried out simulation experiments of 2 km resolution over 12 heavy rainfall events in these three areas and recorded distinct LULC changes in these areas which resulted in deeper and moist boundary areas and higher surface temperature.
Due to the aforementioned conditions, a relatively higher convective available potential energy was recorded and consequently, heavier rainfall.
CAPE is the upward work that buoyancy would perform on a mass of air that is rising upwards. It is basically the amount of energy available for conventions. The higher the CAPE, the higher is the chance of severe weather.
Quarterly Journal of Royal Meteorological Society, published on 18th May 2020 records these findings. The work was done by Dr. Ashok and Mr. Boyaj, the Ph.D. student in collaboration with Dr. Hari Prasad Dasari and Dr. Ibrahim Hoteit of KAUST, Saudi Arabia.
Heavy Urbanization in the southern states of India could be held responsible for the August 2018 floods of Kerala, heavy rainfall in Telangana, and adjoining areas in 2016, September, and Chennai’s severe flash flood during 2015.