Abstract The surface fugacity of CO2 (fCO2) has been measured hourly at a mooring at 8°N, 38°W, using a spectrophotometric CO2 sensor, from June to October 2013. In September 2013, the fCO2 and the sea surface salinity (SSS) decrease significantly. The high precipitation due to the presence of the Intertropical Convergence Zone (ITCZ) and the propagation of low salinity waters from the Amazon River plume explain the decrease of SSS. Indeed, in fall, the retroflection of the North Brazil Current (NBC) feeds the North Equatorial Counter Current (NECC) and transports Amazon waters to the eastern part of the tropical Atlantic. Simulations from a three dimensional physical and biogeochemical model and observations at the mooring show that the Amazon plume reached the mooring in September 2013. The decrease of fCO2 is associated with a moderate peak of chlorophyll. Over the period of the CO2 observations, the site is a source of CO2 to the atmosphere of 0.65 ± 0.47 mmol m−2 day−1. Although the wind speed is at its lowest intensity in September 2013, the flux over the whole period would be about 14% higher without this month. Every month of September from 2006 to 2017, the model simulates a decrease of dissolved inorganic carbon corresponding to the SSS minimum.

中文翻译：

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2013 年 9 月，北纬 8 度、西纬 38 度的二氧化碳减少证明了亚马逊河的传播

摘要 2013 年 6 月至 10 月，使用分光光度法 CO2 传感器在 8°N、38°W 的系泊处每小时测量了 CO2 的表面逸度 (fCO2)。2013 年 9 月，fCO2 和海面盐度 (SSS) ) 显着下降。由于热带辐合带 (ITCZ) 的存在和亚马逊河羽流中低盐度水的传播导致的高降水解释了 SSS 的减少。事实上，在秋季，巴西北部洋流 (NBC) 的逆反射为北赤道逆流 (NECC) 提供能量，并将亚马逊水域输送到热带大西洋东部。三维物理和生物地球化学模型的模拟以及系泊处的观测表明，亚马逊羽流于 2013 年 9 月到达系泊处。fCO2 的降低与叶绿素的中等峰值有关。在 CO2 观测期间，该站点是大气中 0.65 ± 0.47 mmol m-2 day-1 的 CO2 来源。虽然风速在 2013 年 9 月处于最低强度，但如果没有这个月，整个时期的通量将增加约 14%。从 2006 年到 2017 年的每个 9 月，该模型都会模拟与 SSS 最小值相对应的溶解无机碳的减少。