Seasonal Variation of Temperature in Dhaka Metropolitan City, Bangladesh

The present study aims to analyze the impact of global climate change on the basis of seasonal variation of temperature in Dhaka city, Bangladesh. The daily data on temperature from the years 1953-2009 were used and collected from the Meteorological Department, Bangladesh. Pearson correlation analysis, least significant difference techniques and ratio to trend method were used to analyze the data. The results revealed that the temperature of pre-monsoon and winter seasons exhibited an insignificant positive correlation between the periods ‘1953-1971 and 1972-1990’, ‘1972-1990 and 1991-2009’, and ‘1953- 1971 and 1991-2009’. However, the monsoonal and post-monsoonal temperature exhibited insignificant negative correlation between the periods ‘1953-1971 and 1991-2009’, and positive correlation between the periods ‘1953-1971 and 1972-1990’, ‘1972-1990 and 1991-2009’. The least significant difference technique identified the significant differences between the periods ‘1953-1971 and 1972-1990’, ‘1972-1990 and 1991-2009’, ‘1953-1971 and 1991-2009’ during monsoon and winter seasons. It also identified the significant difference in all the periods of four seasons except the periods 1953-1971 and 1972-1990 during pre-monsoon season and the periods 1972-1990 and 1991-2009 during post-monsoon season. Again, the ratio to trend method identified that the lowest average temperature in January, it gradually increased until June, fluctuated in July-October, and then decreased until December.