Variabilitas Iklim Musiman dan Hubungannya dengan Dinamika Luas dan Kondisi Kanopi Mangrove di Belitung Timur

Abstract

Variabilitas iklim musiman dapat berkaitan dengan perubahan kondisi hidroklimatologis dan respons kanopi mangrove. Penelitian ini menganalisis karakteristik iklim, dinamika luas area mangrove terdeteksi, kondisi kanopi, serta hubungan temporal di antara keduanya di Kabupaten Belitung Timur. Data iklim harian 2010-2025 dianalisis bersama citra Sentinel-2 Level-2A 2019-2025. Area mangrove diidentifikasi menggunakan Mangrove Vegetation Index (MVI) dengan ambang yang dikalibrasi terhadap Peta Mangrove Nasional 2024, sedangkan Normalized Difference Vegetation Index (NDVI) digunakan untuk mengklasifikasikan kondisi kanopi. Curah hujan lebih berfluktuasi dibandingkan suhu udara, dengan rata-rata curah hujan 8,88 mm/hari, suhu 26,66 °C dan hujan harian maksimum mencapai 232,3 mm. Juni-Agustus 2019 merupakan musim terkering dengan 160,8 mm hujan, 12 hari hujan, dan 40 consecutive dry days (CDD), sedangkan September-November 2022 merupakan periode terbasah. Rata rata luas mangrove berdasarkan MVI mencapai 9.133,15 ha, maksimum 10.686,75 ha pada September-November 2020 dan minimum 7.068,75 ha pada September November 2023, kanopi lebat mendominasi 82,11% area dengan NDVI valid. CDD satu musim sebelumnya menunjukkan hubungan temporal terkuat dengan kejadian penurunan luas dengan (R² = 0,704), sedangkan curah hujan maksimum satu hari paling lemah. Perubahan area MVI dan NDVI merupakan respons penginderaan jauh dan tidak dapat membuktikan kehilangan tegakan, kesehatan ekologis, atau hubungan kausal tanpa validasi lapangan.

Seasonal climate variability may be associated with hydroclimatic changes and mangrove canopy responses. This study analyzed climate characteristics, detected mangrove area dynamics, canopy condition, and their temporal relationships in East Belitung. Climate data from 2010-2025 were analyzed with Sentinel-2 Level-2A imagery from 2019-2025. Mangrove areas were identified using the Mangrove Vegetation Index (MVI), with thresholds calibrated against the 2024 National Mangrove Map, while the Normalized Difference Vegetation Index (NDVI) classified canopy condition. Rainfall fluctuated more strongly than air temperature, with daily rainfall averaging 8.88 mm/day, temperature 26.66 °C, and maximum daily rainfall reached 232.3 mm. June-August 2019 was the driest season, with 160.8 mm rainfall, 12 rainy days, and 40 consecutive dry days (CDD), whereas September-November 2022 was the wettest season. Mean MVI-detected mangrove area was 9,133.15 ha, reaching 10,686.75 ha in September-November 2020 and 7,068.75 ha in September-November 2023 within dense canopy dominated 82.11% of the NDVI-valid area. One-season-lagged CDD showed the strongest temporal relationship with detected area-decline events (R² = 0.704), whereas maximum one day rainfall was weakest. MVI and NDVI changes represent remotely sensed responses and could not demonstrate physical stand loss, ecological health, or causality without field validation.