基于卫星遥感的南海海-气CO2通量研究.

The ocean is the most important carbon pool in the surface environment. Accurate estimation of CO2 exchange between the sea and the atmosphere is of great significance to further clarify the mechanism of its change process. Using a variety of remote sensing inversion data of sea surface temperature, wind speed, and sea level pressure in the South China Sea (SCS) from 2011 to 2020, a remote sensing estimation model of air-sea CO2 flux was developed based on the air-sea partial pressure difference algorithm, and its temporal and spatial variation characteristics were analyzed. It was shown that: (1) the remote sensing estimation model was highly applicable across the SCS. Compared with the measured regional data, the average absolute error and root mean square error of the estimation results were 1.04 and 1.37 mmol · m-2 · d-1, respectively. The recognition accuracy for identifying source and sink areas was 90.63%. (2) Seasonal variation of CO2 flux in the SCS exhibited higher values in summer and autumn, while lower values were observed in winter and spring. Additionally, there were significant spatial differences between the northern and southern regions of the SCS. The northern area consistently served as a high-value carbon sink, particularly during winter, while the southeastern area of the Indochina Peninsula acted as a carbon source during summer, shifting to the northeast of the SCS during autumn. (3) The CO2 fluxes in three distinct areas of the SCS, namely the northern shelf and slope, central basin, and southern slope, exhibited a decreasing trend over time, with the highest rate of decrease observed in the northern region. From 2011 to 2020, the average annual net carbon release from the SCS to the atmosphere was 1.51 × 107 tons; however, this release exhibited a decreasing trend at a rate of 2.03 × 106 tons per year. Consequently, the overall intensity of the SCS as a carbon source has weakened, suggesting the need for considering these research results when formulating carbon emission and carbon trading policies. [ABSTRACT FROM AUTHOR]