Role of mesoscale low and urbanization on exceptionally heavy rainfall event of 26th July 2005 over Mumbai : Some observational evidences

Abstract

The 26^th July 2005 exceptionally heavy rainfall event over Mumbai has been mainly attributed to a mesoscale low/vortex off Konkan coast and urban heat island (UHI) effect as demonstrated by various research groups. However, these studies are limited on observational evidence regarding the existence of the mesoscale vortex and UHI prior to and during this heavy rainfall event. Hence, a study has been undertaken to examine the existence of the mesoscale low off Konkan coast, which might have triggered this exceptionally heavy rainfall over Mumbai and the possible role of UHI effect over Mumbai on this heavy rainfall event. For this purpose the additional synoptic data from Mumbai high region and daily maximum and minimum temperatures over Mumbai region have been analysed. The analysis confirms the existence of a mesoscale low pressure area and isallobaric low to the west of Dahanu during 25^th - 26^th July 2005. The analysis of daily maximum and minimum temperatures over Mumbai region confirms the UHI effect during 25^th -26^th July, 2005.