Multiple Correlation Between Different Meteorological Parameters in Pre-Monsoon and Monsoon Rainfall over Bangladesh

Abstract

In this research work we have tried to find out the multiple correlation between five meteorological parameters dry bulb temperature, wet bulb temperature, minimum temperature, maximum temperature and rainfall of pre-monsoon season with the rainfall of monsoon season over Bangladesh. Initially correlation coefficients (CC) between different parameters of pre-monsoon season and rainfall of the monsoon have been studied. The correlation coefficients between these parameters with the monthly and seasonal rainfall have been studied. In this research work we have used the data of thirty meteorological stations during 1951 to 2000 all over Bangladesh. We have collected these raw data from Bangladesh Meteorological Department (BMD). We processed these raw data and obtained the monthly and seasonal average. Using these processed data we have analyzed:

1. The average dry bulb temperature (DBT), wet bulb temperature (WBT), minimum temperature (MinT), maximum temperature (MaxT) and rainfall for the month of March, April and May and pre-monsoon season itself. 2. The average rainfall for the month of June, July, August and September and the monsoon season itself. 3. The correlation coefficients between the monthly/seasonal rainfall of monsoon season with the monthly/seasonal DBT, WBT, MinT, MaxT and rainfall of premonsoon season. The multiple correlations between the monthly/seasonal rainfall of monsoon season with the monthly/seasonal DBT, WBT, MinT, MaxT and rainfall of pre-monsoon season. The average DBT gradually increases from the northeastern to the southwestern part of the country. The southern part of the country has the maximum WBT whereas the northern part has the minimum. Starting from the central part of the country the minimum temperature increases towards south and decreases towards north during this season. The highest maximum average temperature exits at Satkhira belt and the lowest at Sylhet. Jessore and some northern part of the country have the minimum rainfall during pre-monsoon season. During monsoon season the maximum rainfall has been recorded at Teknaf, Cox's Bazar and Sylhet region and the minimum rainfall at Jessore, Chandpur and other west and north western belt. From the analysis it has been observed that the correlation coefficient between the premonsoon maximum temperature and monsoon rainfall is positive at most of the places of the central (especially Chandpur and Madaripur), southwestern and a few places of the northern part of the country. It has been found that the correlation co-efficient between the pre-monsoon WBT and monsoon rainfall is positive mostly at the southern, southwestern and the extreme northern part of the country. From this study it has been also found that the multiple correlation co-efficient between the DBT, WBT, MinT, MaxT and rainfall of pre-monsoon and the rainfall of monsoon has a positive value all over the country.