ABSTRACT
Coastal islands across the globe are under threat due to recurring water logging conditions caused by climatic extremes (cyclones), local topographic conditions, human interventions, an unprecedented wave actions enhancing the regional exposure and hampering livelihood of the habitants. IPCC 2014 emphasises about the coastal inundations due to sea-level rise, anthropogenic activities, and extreme climatic conditions. Sagar a coastal island located in South 24 Pargana district and part of Sundarbans mangrove forests in the mid1800s, this island has seen a largescale transformation in the landscape with now supporting human habitations, agriculture, socio-economic activities, goods, and services, etc. The island has witnessed super cyclones, unprecedented tidal variations, continually rising sea levels, etc. causing socio-economic complications. The current research aims to visualize and model (connected N8 model) the exposure conditions by using recent high-resolution remote sensing data of spatial resolution of 2.5m, 5m, and 10m along with secondary data using advanced geospatial techniques. Increasing paved surfaces in the island show a strong relationship with increasing human habitation in this island due to the submergence of the neighbouring islands. Long-term assessment of temperature and rainfall events depicts an increasing trend in annual average temperature and increasing high rainfall events in the pre and post-monsoon seasons indicating rising instances of cyclonic hazards. Assessment of long-term observation of Sea level rise demonstrates an increasing sea level of 0.46m by 2050. The results indicate that the southern and eastern portion of the island is exposed to inundation due to the sea level rise, as well as surge. Analysis of SAR data about cyclonic events Yaas and Amphan demonstrate most parts of the Island on North, South, and East are more affected by Cyclonic hazards. The assessment provides both awareness and knowledge helping to focus on investigations and preparedness levels to different water inundation levels relative to climatic circumstances.
