Observing the influences of climatic and environmental variability over soil salinity changes in the Noakhali Coastal Regions of Bangladesh using geospatial and statistical techniques

Abstract

Climate change is an intensive threat to the coastal areas of Bangladesh. Low-lying coastal areas suffer from salinity intrusion, especially in the geomorphologically active central coastal areas of Bangladesh (CAB). The intrusion of soil salinity has been particularly evident from studies on the CAB, which exhibits the effects of climate change and salinity changes along the coast. On a local scale, studies like these are essential, but current, when dealing with climate-driven changes considering the field of study, it is rarely observed and recorded in the literature. Therefore, this present study focuses on observing the influence of climate and environmental variability over soil salinity changes trend in the Noakhali coastal regions (NCR) of Bangladesh using geospatial and statistical techniques. To achieve this goal, the present study analyzed the historical climatic data of Bangladesh Meteorological Department (BMD) from 1987 to 2018, which showed that there were irregularities with deviation from normal distribution of temperature and rainfall data in the region. The study also shows maximum temperature raise of about 3°C and 1500 mm annual rainfall in the area. In addition, amplification of tides have been observed in the east and decreases in the west coast. On the other hand, the study suggested a significant reduction of about 22 dS/m in soil salinity data analysis from 1996 to 2019, which was a maximum of 2.27 dS/m in 2019 compared to 25 dS/m in 1996. However, in-depth observations of temperature and rainfall data revealed strong seasonal control over soil salinity levels. Abundance of rainfall is negatively correlated where tidal level is positively correlated with soil salinity level of the study area. There is a positive correlation between the soil salinity level and a minimum level of temperature change. The present study systematically focuses on the change in soil salinity of the NCR on climate and environmental changes, which provides information on historical influence. Finally, the study confirms that rainfall and tides are the main and temperature as the secondary soil salinity controlling factors of the CAB. The results of this study might be used scientifically to attain the sustainable agricultural practices, coastal development and regional planning of the country.