ALGORITHMS DEVELOPMENT OF THE FIELD MANGROVE CHLOROPHYLL-a BIOMASS, CARBON BASED ON SENTINEL-2A DATA AT CAWAN ISLAND, SUMATERA, INDONESIA

Agus HARTOKO , Aulia RAHIM, Nurul LATIFAH

DOI: 10.21163/GT_2022.172.11

ABSTRACT: The study develop of algorithms for the tropical mangrove chlorophyll-a, biomass and carbon based on the field data measurements at Cawan Island Sumatera Indonesia and Sentinel-2A satellite data. Samples of mangrove leaf were used for chlorophylla-a measurements using spectrometry method. Field sampling data using purposive sampling method. Data of mangrove tree diameter at breast height (DBH) was processed using allometric equation to estimate the mangrove biomass and carbon content. Algorithms were developed after performing a series of polynomial regressions of field and Sentinel-2A satellite data and then select the highest correlation coefficient. The dominant mangrove is Rhizophora apiculata. The field mangrove leaf chlorophyll-a content ranged from 14.03-15.77 mg.ml^-3, while the estimated chlorophyll-a from algorithm is in the range of 13.714-16 mg.ml^-3. Calculated field mangrove biomass is in the range of 66.31-85.05 tons.ha^-1, while the value from algorithms is in the range of 51-90 tons.ha-1. The highest biomass and carbon storage is in the trunks. This study produces the algorithm of mangrove leaf chlorophylll-a = 0.0002((B₄ + B₂)/2)² – 0.057((B₄ + B₂)/2) + 16.79, with RMSE of 0.072 mg.m^-3. Algorithm for mangrove biomass = 24.69(B₄/Band₂)² - 47.41(B₄/B₂) + 36.06, with RMSE of 0.337 tons/0.2ha and algorithm for mangrove carbon = 10.071(B₄/B₂)² – 23.159(B₄/B₂) + 44.233; with RMSE of 0.235 tonsC/0.2ha. The new insight in this study is that the algorithm developments can be applied for mangrove chlorophyll-a content, biomass and carbon content estimation using any optical satellite data based on its relevant spectral range. This algorithm development is an open approach method based on highest correlation coefficient on regression equation of the field and the satellite spectral value. The algorithms resulted from this study can be applied over wide and in any area in the tropics.

Keywords: Mangrove, Chlorophyll-a, Biomass, Carbon, Sentinel-2A, Algorithm

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