a Civil Engineering Department, Pandit Deendayal Petroleum University, Gandhinagar. b Indian Meteorological Department, Meteorological Centre, Ahmedabad. c Space Application Centre, Indian Space Research Organization, Ahmedabad. d Institute of Rural Management, Anand, Gujarat 388001, India. e Alpha College of Engineering and Technology, Ahmedabad.
There is a global change in the climate and cities are looked as the key culprits of this change. India will undergo an immense urbanization in the coming decades, doubling its urban population by 2050. Thus it is very important to understand the dynamics of the changing urban climate of Indian cities. With this background, the present urban climate change study is conducted for the Vadodara city located in the state of Gujarat, India using the hourly Dry Bulb Temperature (DBT) and Wet Bulb Temperature (WBT) available at 00-hr, 03-hr, 06-hr, 09-hr, 12-hr, 15-hr, 18-hr and 21-hr for a period of 37 years (1969-2006). The hourly DBT and WBT for the 12 months were bunched on hourly-monthly basis (thereby having 192 specific bunches) for the study period which were then analyzed using the Mann-Kendall trend test at different confidence limits (90%, 95% and 99%). The findings reveal that there is an overall increase in the temperature of the city as for 78% of the time the DBT had an increasing trend and 52% of the time WBT had an increasing trend. For the first half of the day (03-hr to 12-hr) both the DBT and WBT had an overall increasing trend while in the second half of the day (15-hr to 0-hr) DBT had an overall increasing trend and WBT had an overall decreasing trend. This contrasting behavior of the DBT and WBT was specifically seen in the months of May-July which are largely the monsoon months. For both DBT and WBT, the month of February had the overall maximum increasing trend while the month of August had the overall maximum decreasing trend. The present study statistically quantifies the changing urban climate of Vadodara city and these findings would not only add to the pool of knowledge to understand the dynamics of the changing urban climate but will be of ready reference for the policy makers to initiate appropriate measures for mitigation and adaptation.