Mean sea level in Bangladesh

Abstract

This article focuses mainly on variations in mean sea level along the coast of Bangladesh. Six tidal stations along the coast of Bangladesh were selected for this study. The monthly, annual, and 5‐year variations of mean sea level for the period 1977–1990 are presented. The monthly mean at all six stations with respect to the 14 years average are taken into account. The study shows that there are strong seasonal variations in the monthly mean sea level. The sea level is highest in June, July, or August, which coincides with the rainy or monsoon season in Bangladesh and is the time of maximum discharge in all rivers. The sea level is lowest during January, February, or March, due to the dry winter season. Large fluctuations due to weather conditions tend to balance through the years, and the periodic seasonal changes are mostly eliminated when annual averages are calculated for the same six stations. The annual sea levels have been smoothed by taking a 5‐year running average to show the trend. The data are not adequate to draw any conclusion on the long‐term changes of the sea level. This study also discusses the difficulties of maintaining data suitable for the study of long‐term changes in the sea level, and gives direction for future improvements.