Publications

Lu, HY; Bai, Y; Chen, XY; Gong, F; Zhu, QK; Wang, DF (2017). Satellite remote sensing of the aquatic pCO(2) in the basin of the South China Sea. REMOTE SENSING OF THE OCEAN, SEA ICE, COASTAL WATERS, AND LARGE WATER REGIONS 2017, 10422, UNSP 1042218.

Abstract
The South China Sea (SCS) is one of the largest marginal seas in the world, and the air-sea CO2 flux in the SCS may contribute significantly to the global air-sea CO2 flux. In the past decade, many researches on the aquatic pCO(2) and air-sea CO2 flux mainly in the north SCS were carried out based on the underway measurement of the pCO(2), and the results revealed that the SCS is a source of the CO2 as a whole in the annual scale. However, the air-sea CO2 flux is high spatial variability in the SCS, for example, the north shelf of the SCS is a CO2 sink while the basin is a source. To monitor the spatial and temporal variations of the air-sea CO2 flux in the SCS, few satellite remote sensing algorithms have been developed to estimate the aquatic pCO(2) in the north SCS. However, these algorithms are all the empirical models which depend on the training dataset from the in situ measurement. In this study, we apply the semi-analytical algorithm MeSAA to retrieve the aquatic pCO(2) in the SCS basin. The MeSAA algorithm was proposed by the Bai et al. (2016) and was evidenced to be widely applicable to the different marginal seas including the East China Sea and Bering Sea. Based on the underway measured aquatic pCO(2) and water temperature, we found that the variation of the pCO(2) in the SCS basin is mainly controlled by the temperature. In addition, the increase of the atmosphere pCO(2) can also contribute the systematical increase of the aquatic pCO(2). Therefore, we established a semi-analytical algorithm for the aquatic pCO(2) retrieval in the SCS basin, which considers the thermodynamic effect and air-sea CO2 fluxes. The results showed that the thermodynamic effect in the SCS basin was consistent with the theoretical result with the aquatic pCO(2) increasing 4.23% for the 1 degrees C rising of the water temperature. Moreover, the satellite-retrieved aquatic pCO(2) match well with the in situ pCO(2). Based on the established algorithm, the monthly time-series of the aquatic pCO(2) in the SCS basins from 2003 to 2016 were generated from the MODIS datasets from both the Aqua and Terra satellite, and the long-term trends of the aquatic pCO(2) in the different parts of the SCS basin were analyzed.

DOI:
10.1117/12.2278057

ISSN:
0277-786X