Global sea level rise (SLR) has emerged as a pressing concern because of its impacts, especially increased vulnerability of coastal urban areas flooding. This study addresses the pressing concern of SLR and flood vulnerability in the East Coast of North Sumatra (ECNS) and Medan City. We employ a data-driven approach integrating multicriteria analysis, analytical hierarchy process (AHP)-based weighting, and spatial modeling within a geographic information system framework. The analysis considers crucial factors such as slope, land use, soil type, SLR, and land deformation. The study expands the existing framework by incorporating SLR and land subsidence, acknowledging their significant roles in exacerbating flood vulnerability. Future flood-intensity scenarios are simulated based on SLR projections. Data for spatial analysis primarily originated from multisensor satellite imagery, secondary sources from published literature, and field surveys. We validated the consistency of the variable weightings assigned for vulnerability analysis using a consistency ratio threshold (<0.1). Finally, the established flood vulnerability model was validated by comparing its predictions with recorded flood events in the ECNS and Medan City. The ECNS and Medan City areas were classified as very high and highly vulnerable to flooding, respectively.

The phenomenon of sea level rise (SLR) in Pangandaran Regency threatens the continuity of human activities such as tourism, fisheries and trade that gives value to coastal regions. The southern coast of Java directly faces the Indian Ocean and sea levels are expected to rise by 2 – 4 mm/year, leaving the Pangandaran Regency relatively vulnerable to SLR. Coastal vulnerability can be mapped using the Coastal Vulnerability Index method to determine levels of vulnerability based on six parameters which are geomorphology, elevation, tidal range, significant wave height (SWH), shoreline change and rate of SLR. The results show that the geomorphology of Pangandaran Regency is considered to be very vulnerable (Score 5) due to the number of sandy beaches present. Elevation is dominated by the vulnerable category (Score 4). Tidal range of the coastal region is considered moderately vulnerable (Score 3). SWH of the coastal region is very vulnerable (Score 5). Shoreline change is considered to be moderately vulnerable (Score 3) with overall erosion in the region. Rate of SLR is considered to be very vulnerable (Score 5). The coastal region Pangandaran Regency is leaning towards being vulnerable against sea level rise.

The melting of polar ice caps due to climate change has resulted in sea level rise that threatens coastal areas, such as the Demak Regency. The impact of tidal flooding is, exacerbated by land subsidence. This study aimed to map and predict the distribution of tidal flooding in coastal Demak and its impact on land use. The methods used included Differential Interferometry Synthetic Aperture Radar (DInSAR) for Land Subsidence (LS), supervised classification for land use, admiralty for tides, data visualization for elevation, linear regression analysis for SLR, meteorological data analysis for wind and rainfall, and spatial analysis for tidal flood inundation mapping. The results showed an LS rate of 2,74 cm/year, highest tide height of 61,93 cm, average elevation of 1,893 m above sea level, SLR rate of 0,435 cm/year, wind speed of 0,5-5,7 m/s blowing from the northwest, and average daily rainfall of 7,476 mm. The tidal flood inundation area in 2023 reached 8.954,6 hectares and is predicted to reach 11.394,5 hectares in 2031. Tidal flooding affects mangroves (523,6 hectares), ponds (3.857,9 hectares), settlements (1.095,4 hectares), industries (3.453,00 hectares), and rice fields (24,7 hectares).

The increase in ocean temperature causes the expansion of seawater volume, resulting in an increase in sea level rise. The phenomenon of land subsidence also exacerbates the occurrence of tidal floods in coastal areas of Indonesia. This has prompted the need for a study of land subsidence and the distribution of tidal floods in Tangerang as a basis for taking anticipatory steps to reduce the negative impacts. The methods used for estimating land subsidence involved the SAR Sentinel-1A. The research utilized a total of 170 data points, spanning from 2017 until 2022. Data processing was carried out using the Parallel Small Baseline Subset method. The supporting data used in this study included SRTM data, tidal range, rainfall data, wind speed and direction. The results of this study reveal that the city of Tangerang has a maximum deformation value of -10.8 cm per year in the Periuk Sub District. Meanwhile, Tangerang Regency experienced land subsidence at a rate of -8.6 cm per year in Kosambi Sub District. Significant subsidence deformations occurred on the northeast side of Tangerang District and the southeast side of Tangerang City. Based on data analysis, it is evident that the total area inundated by tidal floods in Tangerang covers 33.267 hectares, with the largest affected area being in Pakuhaji District, spanning 9,262 hectares.

Coastal flooding is the overflow of seawater during high tide causing inundation in the coastal area with low elevation. This study aimed to determine the distribution of the tidal flood area on the coast of Pandeglang Regency, Banten, using the geospatial information system method. The distribution of the flood area is obtained from the separation of land and water areas with the use of Landsat 8 OLI imagery extraction which will be adjusted to land elevation data from DEMNAS. The distribution area of the flood is also determined by other factors such as land subsidence, wind speed and direction, rainfall, and tides at the research location. The results show that in December 2020 the highest tide reached 0.736 m, the highest rainfall accumulated was 25.6 mm per day, with the wind direction dominated towards the west with a speed of 3.60 m s^–1 – 8.80 m s^–1, and the land subsidence rate varied spatially from 1-14 cm year^–1. After combining the data, the distribution of flood areas in Pandeglang Regency showed that there was 1.232 ha or 3.64% of an inundated area on the coast of Pandeglang Regency with 4 sub-districts affected by the flood.

Flood disasters have become an annual occurrence along the East Coast of North Sumatra (ECNS) and Medan City. Numerous studies have examined the causal factors flood disasters in this area, such as changes in land use, drainage issues, and population growth, but the intensity of flood disasters continues to rise. In this research, we focused on evaluating the unexplored factors of land subsidence and rising sea levels in this region. Our investigation uses multi-sensor satellite data and field surveys to conduct an assessment of the rate of land subsidence and sea level rise and assess their implications on flood disasters. This study highlights the potential of multi-sensor satellite data as a primary resource for assessing flood disasters in coastal areas and densely populated large cities. Furthermore, we propose a solution to reduce the negative impact of flood disasters by by engaging local communities and environmental enthusiasts in mangrove reforestation along the coastline.