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Banaras Hindu University (2015)

Some studies on trends and variability of extreme temperature and precipitation over India

Some studies on trends and variability of extreme temperature and precipitation over India

Titre : Some studies on trends and variability of extreme temperature and precipitation over India

Auteur : Srivastava,Abhay Kishor

Université de soutenance : Banaras Hindu University

Grade : Doctor of Philosophy (PhD) 2015

Résumé
There has been a lot of discussion and research in the scientific and political realm about the evidence of climate change in connection to the green house effect and expected global warming over the globe. Present work mainly focused on the annual, seasonal and monthly variability and trend in temperature/ extreme temperature as well as mean rainfall /extreme rainfall over Indian region in the recent decades. Sen’s non-parametric estimator of slope has been used to estimate the magnitude of trend, while statistical significance was assessed by the Mann–Kendall test. The trends significant at ≤ 5% significance level are considered as significant trend in the present work. The mean monthly temperature data has been taken from IITM (Indian Institute of Tropical Meteorology) website (http://www.tropmet.ac.in) in the period of 1975-2007over seven homogeneous temperature regions (i.e. western Himalaya (WH), Northwest (NW), North Central (NC), North East (NE), Interior peninsula (IP), East coast (EC) and West coast (WC) and India as a whole. Similarly, daily observed data of maximum and minimum temperature of the period of 1975-2007 is obtained from IMD for the wide spread 23 stations over different climatic subdivisions over India. The above mentioned data is utilized to detect the trend and variability in maximum temperature, minimum temperature mean temperature, highest maximum temperature, lowest minimum temperature, diurnal temperature range and mean temperature over large aggregate region as well as over different subdivisions over Indian region The trends and variability of the temperature indices hot/cold days and night is also worked out

On the basis of analysis of temperatures, the mean temperature of India as a whole is found to be 24.50C with an inter-annual variability of 1.1%. On seasonal scale, the monsoon season (JJAS) illustrated highest mean temperature in all the homogeneous zones except IP and EC region where it occurred during pre-monsoon season (MAM). The mean temperature is highly fluctuating during winter season (JF) in all the homogeneous zones and over India as a whole and least during monsoon season. Most significant upward trend in mean temperature over the country as a whole is observed only during winter and monsoon season at the rate of 0.16 0C and 0.28 0C/ decade respectively. Most significant warming trend in mean temperature during all the seasons is observed over WH and WC region.

Présentation et version intégrale (Shodhganga)

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