In what may be interpreted as another sign of climate change, the maximum April temperature in Pune for the past three years has failed to cross the 40 degrees Celsius mark. This, scientists from both India Meteorological Department (IMD) and Indian Institute of Tropical Meteorology (IITM), say could be the reason for the lack of proper pre-monsoon thundershowers in the city in these few years.
The past 10 years, ie from 2003-2013 (till April 28), shows that barring the past two years and till date for this year, the highest temperature recorded in April has been over 40 degrees Celsius.
The mean temperature of April recorded between 2003-2012 hovered between 37 and 38 degrees Celsius over the year. The highest temperature recorded both in 2011 and 2012 has been in the range of 38 and 39 degrees Celsius. This year till date, the highest recorded temperature for April was 39.7 (on April 12). The highest-ever April temperature recorded in Pune was 43.3 degrees Celsius on April 30, 1897.
Although, the mean temperature has not changed much, the drop in the highest temperature has affected the pre-monsoon showers in the city.
While talking about this trend, Dr R Krishnan, senior scientist of IITM, said the lower temperature is due to the low level of "heat" during April in the city. Normally summer is supposed to be at its peak in Pune during April, with the highest seasonal temperatures often being recorded in April.
"The heat coefficient, which determines the temperature in the area, might have been lower for the past two to three years, which is reflected in mercury not rising above the 40-degree mark," he said.
Local climatological factors like wind direction and moisture content could also be behind this trend.
An important fallout of this trend has been the absence of substantial pre-monsoon showers in the city.
An IMD research has shown that pre-monsoon showers have become spare this year. Other than negligible rains in the first week of April, no pre-monsoon showers have been witnessed in the city.
For thundershowers to develop, proper temperature and moisture content in the wind are necessary. "Maybe the temperature or the moisture level have not been high enough for thundershowers to develop in the past few years,," Dr Krishnan suggested.
