Aurin Dirk, Mannino Antonio, Lary David J
NASA Goddard Space Flight Center (USRA), Greenbelt, MD 20771, USA.
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA;
Appl Sci (Basel). 2018;8(12):2687. doi: 10.3390/app8122687. Epub 2018 Dec 19.
A Global Ocean Carbon Algorithm Database (GOCAD) has been developed from over 500 oceanographic field campaigns conducted worldwide over the past 30 years including in situ reflectances and coincident satellite imagery, multi- and hyperspectral Chromophoric Dissolved Organic Matter (CDOM) absorption coefficients from 245-715 nm, CDOM spectral slopes in eight visible and ultraviolet wavebands, dissolved and particulate organic carbon (DOC and POC, respectively), and inherent optical, physical, and biogeochemical properties. From field optical and radiometric data and satellite measurements, several semi-analytical, empirical, and machine learning algorithms for retrieving global DOC, CDOM, and CDOM slope were developed, optimized for global retrieval, and validated. Global climatologies of satellite-retrieved CDOM absorption coefficient and spectral slope based on the most robust of these algorithms lag seasonal patterns of phytoplankton biomass belying Case 1 assumptions, and track terrestrial runoff on ocean basin scales. Variability in satellite retrievals of CDOM absorption and spectral slope anomalies are tightly coupled to changes in atmospheric and oceanographic conditions associated with El Niño Southern Oscillation (ENSO), strongly covary with the multivariate ENSO index in a large region of the tropical Pacific, and provide insights into the potential evolution and feedbacks related to sea surface dissolved carbon in a warming climate. Further validation of the DOC algorithm developed here is warranted to better characterize its limitations, particularly in mid-ocean gyres and the southern oceans.
全球海洋碳算法数据库（GOCAD）是根据过去30年在全球范围内开展的500多次海洋学实地考察数据开发而成，这些数据包括现场反射率和同步卫星图像、245 - 715纳米范围内的多光谱和高光谱发色溶解有机物（CDOM）吸收系数、八个可见光和紫外波段的CDOM光谱斜率、溶解有机碳和颗粒有机碳（分别为DOC和POC），以及固有光学、物理和生物地球化学特性。利用现场光学和辐射数据以及卫星测量数据，开发了几种用于反演全球DOC、CDOM和CDOM斜率的半分析、经验和机器学习算法，对其进行了全球反演优化并验证。基于这些最可靠算法的卫星反演CDOM吸收系数和光谱斜率的全球气候学滞后于浮游植物生物量的季节性模式，这与一类水体假设不符，并在大洋盆地尺度上追踪陆地径流。卫星反演的CDOM吸收和光谱斜率异常的变化与厄尔尼诺 - 南方涛动（ENSO）相关的大气和海洋条件变化紧密耦合，在热带太平洋的大片区域与多变量ENSO指数强烈共变，并为变暖气候下与海表溶解碳相关的潜在演变和反馈提供了见解。有必要进一步验证此处开发的DOC算法，以更好地描述其局限性，特别是在大洋中涡和南大洋。
