milan米兰体育官网 用于反演中国湖泊溶解有机碳浓度的卫星算法

引用

Liu D、Spyrakos E、Tyler A、Shi K 和 Duan H (2024) 用于反演中国湖泊溶解有机碳浓度的卫星算法。整体环境科学，955，艺术。编号：177117。https://doi.org/10.1016/j.scitotenv.2024.177117

摘要
Water quality and the carbon cycle in lakes are strongly related to the concentration of dissolved organic carbon (DOC). Several regional algorithms have been proposed to remotely retrieve lake DOC concentration at a regional scale, but further efforts are needed to reliably retrieve DOC concentration over a large area. Based on bio-optical measurements from 55 lakes across China, this study investigates feasible satellite algorithms for retrieving DOC concentrations from OLCI/Sentinel-3 imagery. The results revealed that the bio-optical characteristics of DOC were different in freshwater and saline lakes. Compared to saline lakes, freshwater lakes had lower DOC concentrations (9.89 ± 3.97 mg/L vs. 32.97 ± 42.07 mg/L) but similar levels of colored dissolved organic matter as indicated by its absorption coefficient at 280 nm (aCDOM(280), 12.8 ± 6.94 1/m vs. 17.15 ± 22.97 1/m). Moreover, DOC concentrations in freshwater lakes were exponentially related to aCDOM(280) (r = 0.74) and linearly correlated with red-to-green reflectance ratios. However, DOC concentration in saline lakes was linearly related to aCDOM(280) (r = 0.93) and exponentially correlated with red-to-blue reflectance ratios. Then, although we discriminated freshwater and saline lakes with a conductivity threshold of 2000 μs/cm, the three commonly used linear regression methods for estimating DOC concentrations still obtained mean absolute percent difference (MAPD) of 55.68–66.44 %. Alternatively, we developed a hybrid machine learning algorithm (MAPD = 18.16 %), that used water reflectance and lake/basin properties to model DOC concentrations in freshwater and saline lakes, respectively. Satellite monitoring of 370 large lakes (>20 km2)表明我国DOC浓度西北高、东南低。这项研究对于利用卫星图像动态监测湖泊中 DOC 浓度具有重要意义。

关键字
生物光学特性；溶解有机碳；卫星监测；时空变化；驱动因素

期刊
整体环境科学：第 955 卷