Key findings:
The CBR-PSO model incorporating Sentinel-1, Sentinel-2, and ALOS-2 PALSAR-2 data estimated the mangrove soil organic carbon (SOC) ranging from 44.74 to 91.92 Mg ha−1 (average = 68.76 Mg ha−1).
The proposed model yielded a satisfactory accuracy (R2 = 0.809, RMSE = 9.30 Mg ha−1) and outperformed the RF, the SVM, and the XGBoost models
Multisensor optical and SAR combined with the CBR-PSO model can be accurately estimated the mangrove SOC in the Red River Delta, Vietnam.
Key findings:
The XGBR-GA model incorporating Sentinel-2, Sentinel-1, and ALOS-2 PALSAR-2 data to estimate the mangrove above-ground biomass (AGB), including small and shrub mangrove patches was proposed
The proposed model yielded a promising result (R2 = 0.683, RMSE = 25.08 Mg·ha−1) and outperformed the four other ML models
Multisource optical and SAR combined with the XGBR-GA model can be used to estimate the mangrove AGB in North Vietnam.
Key findings:
The XGBR model produced a promising result with R2 = 0.805, RMSE = 28.13 Mg ha-1, and produced the highest prediction performance among the five machine learning models.
The XGBR model estimated mangrove AGB ranging between 11 and 293 Mg ha-1 (average = 106.93 Mg ha-1).
A fusion of Sentinel-2 MSI and ALOS-2 PALSAR-2 sensors combined with the XGBR model can accurately estimate mangrove AGB in the tropics.
RoF produced the highest overall accuracy than those of RF and CCF algorithms in mapping mangrove species and seagrass meadow
The potential use of Sentinel multispectral and SAR data together with ensemble-based machine learning techniques to map mangrove species
Key findings
Willingness to pay (WTP) is elicited by single-bound dichotomous choice model.
Perceptional factors influencing the WTP of respondents are examined.
Socio-demographic factors influencing the WTP for mangrove restoration are evaluated.
The annual mean WTP per household is estimated as VND 192,780 (US$ 8.6).
Highlights
Overview of Earth Observation data, machine learning and state-of-the-art deep learning techniques used to quantify above-ground carbon, below-ground carbon, and soil carbon stocks of mangroves, seagrasses and saltmarshes ecosystems;
Key limitations and future directions for the potential use of data fusion combined with advanced machine learning, deep learning, and metaheuristic optimisation techniques for quantifying blue carbon stocks are also highlighted.
Highlights
Overview and summary of the key studies undertaken from 2010 onwards on remote sensing applications for mapping and monitoring BC ecosystems
Optical imagery, such as multispectral and hyper-spectral data, is the most common for mapping BC ecosystems
Highlights
Overview of the techniques that are currently being used to map various attributes of mangroves
Key future directions for the potential use of remote sensing techniques combined with machine learning techniques
ALOS-2 PALSAR-2 for 2015 achieves an overall accuracy of 85% and the kappa coefficient of 0.81, compared with those of 81% and 0.77, respectively from the ALOS PALSAR for 2010.
Mangrove forest areas in the Cat Ba Biosphere Reserve, Vietnam decreased by 15% from 2010 to 2015.