Trends in surface temperature variability over Mumbai

Abstract

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Observational evidence points to a warming trend in surface temperatures over the globe. This paper focuses on the trends in Maximum and Minimum temperatures over Mumbai. The temperature trends were investigated at different temporal scales from decadal to daily. The seasonal series were also investigated for trends in frequency of occurrences of extreme events. In general an increasing trend is observed over Mumbai, with the increase in Maximum temperatures more than the Minimum temperatures and statistically significant at 95% confidence level.  A seasonal distinction is evident with the warming more in the Winter and Post Monsoon seasons as compared to the Pre Monsoon and Monsoon seasons at both the inter-annual and intra-seasonal scales of investigation. The seasonal distinction was also evident in the extreme temperature analysis. The frequency of occurrences in the hot days and hot nights were more pronounced in the Pre Monsoon and Monsoon seasons as compared to the Winter and Post Monsoon seasons. Symmetric warming trend was observed for both the daytime and nighttime temperatures at both the stations in all the seasons though the variations at Santacruz are statistically insignificant in the Post-Monsoon season