Sea Level Variations in the Bay of Bengal using Satellite Altimetry and Tide Gauge Records

Amin, M.K. and Hasan, G.M.J., 2024. Sea level variations in the Bay of Bengal using satellite altimetry and tide gauge records. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 215-219. Charlotte (North Carolina), ISSN 0749-0208. Sea-level rise (SLR) poses a significant threat to coastal and deltaic populations around the world, and Bangladesh is particularly vulnerable, as nearly half its people occupy low-lying regions which are highly exposed to flooding dangers from rising sea levels. This study aims to assess the trends of sea levels utilizing the tide gauge record, and comparing with regional and global sea level trends using satellite data over the recent past. The analysis included tide data from seven stations, which were collected from BIWTA and BWDB, spanning three coastal zones of Bangladesh. The trends of annual mean tidal water levels were estimated using both linear and non-linear methods. The average rate of SLR calculated from seven tide gauge data in the Bay of Bengal using a linear trend method varies between 1.2 and 10.1 mm/year. SLR changes were projected until 2100, based on the developed equation for the linear trend line of the historical record. This study forecasted that in 2050 and in 2100, the Bay of Bengal Sea level change will range from 60–303 mm and 160–808 mm, respectively. The study also used satellite data collected from the NOAA, where TOPEX, Jason-1, -2, and -3 satellites show that the SLR has been faster in the Bay of Bengal over the last 30 years, which is around 3.99 mm/year compared to the global average of 3.06 mm/year. This study used the Norwegian Earth System Model of CMIP6 to compare the mean SLR of regional and global trends, where Barguna and Sandwip stations out of the seven stations surpass the projections for the year 2100. The estimated non-linear trends in 2100 at Charchanga, Cox's Bazar, and Hiron Point stations satisfy the data retrieved from the IPCC AR6 report. The results of this study offer valuable insights into developing strategies to alleviate the possible negative impacts of SLR and adjust to the changing coastal surroundings.