Electronic Theses and Dissertation

Penelitian ini bertujuan untuk memetakan sebaran dan menganalisis perubahan tutupan mangrove di Pulau Weh, Kota Sabang, menggunakan citra satelit Sentinel-2A pada dua periode, yaitu tahun 2019 dan 2023. Sebanyak 11 lokasi area mangrove ditetapkan sebagai objek penelitian berdasarkan hasil digitasi manual dan verifikasi lapangan. Metode yang digunakan menggabungkan indeks vegetasi NDVI (Normalized Difference Vegetation Index) dan NDWI (Normalized Difference Water Index), yang kemudian diklasifikasikan secara logika biner untuk membedakan antara piksel mangrove (nilai 1) dan non-mangrove (nilai 0). Proses klasifikasi dilakukan secara terpisah untuk masing-masing tahun, kemudian dianalisis menggunakan metode raster calculator dan zonal histogram di ArcMap 10.8 untuk mengidentifikasi tiga kategori perubahan: kehilangan mangrove (–1), tetap mangrove (0), dan pertambahan mangrove (+1). Hasil analisis menunjukkan peningkatan luas mangrove sebesar +3,51 hektar dalam kurun waktu 2019–2023, dengan laju perubahan 0,68 ha/tahun. Pertambahan terbesar terjadi di lokasi 09 (Desa Iboih) sebesar +1,62 ha, sedangkan penurunan terbesar terjadi di lokasi 10 (Desa Batee Shoek) sebesar –0,03 ha. Luasan mangrove tertinggi pada 2023 tercatat di lokasi 09 seluas 42,79 ha. Lokasi lainnya menunjukkan perubahan yang tidak signifikan, mencerminkan kondisi ekosistem yang relatif stabil. Temuan ini menunjukkan bahwa penggunaan citra Sentinel-2A efektif dalam memantau perubahan tutupan mangrove secara spasial dan temporal, serta berpotensi mendukung perencanaan konservasi dan pengelolaan sumber daya pesisir berbasis bukti ilmiah.
Kata kunci : mangrove, Pulau Weh, Sentinel-2A, NDVI, NDWI, perubahan tutupan,
penginderaan jauh, klasifikasi spasial

This study aims to map the distribution and analyze changes in mangrove cover on Weh Island, Sabang City, using Sentinel-2A satellite imagery for two periods, namely 2019 and 2023. A total of 11 mangrove areas were designated as research sites based on manual digitization and field verification. The method used combines the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI), which were then classified using binary logic to distinguish between mangrove pixels (value 1) and non-mangrove pixels (value 0). Classification was conducted separately for each year, followed by change detection analysis using the raster calculator and zonal histogram methods in ArcMap 10.8 to identify three categories of change: mangrove loss (–1), unchanged mangrove (0), and mangrove gain (+1). The results showed an overall increase in mangrove area of +3.51 hectares from 2019 to 2023, with a rate of change of 0.68 ha/year. The most significant gain occurred at location 09 (Iboih Village), with an increase of +1.62 ha, while the largest decrease was recorded at location 10 (Batee Shoek Village) with –0.03 ha. The highest total mangrove area in 2023 was observed at location 09, covering 42.79 ha. Other locations showed insignificant changes, indicating relatively stable ecosystem conditions during the observation period. These findings suggest that Sentinel-2A imagery is effective for monitoring spatial and temporal changes in mangrove cover and supports evidence-based decision-making in coastal resource management and conservation planning. Keywords : mangroves, Weh Island, Sentinel-2A, NDVI, NDWI, cover change, remote sensing, spatial classification