本研究以CFC-12数据为基础，基于 “转移时间分布”方法开展苏禄海上层水体的通风过程及时间尺度研究，并估算苏禄海人为碳含量，并采用一维平流扩散模式和瞬时稳态理论探讨研究海域的垂直扩散率和上升速率。估算结果表明苏禄海在2011年人为碳储量为81 Tg（误差范围：66-98 Tg），水柱人为碳储量为39 mol∙m^-2（误差范围：30-49 mol∙m^-2）。不过相较太平洋而言，其储存人为碳的能力较低，主要原因在于苏禄海没有深层水生成的机制，人为碳信号无法大量进入深层水体。通过与反算法得到的结果进行比较，表明反算法高估了苏禄海的人为碳数值。基于“瞬时稳态”概念，结合人为碳数据，我们估算出苏禄海的混合层以深垂直扩散率下限值为1.1×10^-4 m² s^-1 (误差范围：0.7-1.8×10^-4 m² s^-1)。相关文章《Ventilation and Anthropogenic CO2 in the Sulu Sea》于2017年1月发表于海洋学SCI期刊《Journal of Marine Systems》。

Abstract:

The Sulu Sea, a semi-enclosed deep marginal basin, has limited exchange of deep water and poorly constrained ventilation time-scales. Here we use observations of the transient tracer CFC-12 to calculate the ventilation time-scale and the concentration of anthropogenic CO₂ (C_ant) in the Sulu Sea based on the transient time distribution (TTD) method. We found that CFC-12 has penetrated the entire water column in the Sulu Sea and the mean ages increase with depth monotonically and exceed 400 years below the depth of about 2500 m. The mean ages derived from CFC data in the Sulu Sea below about 500 meter are lower than those in the South China Sea (SCS) at the same depth, indicating that the ventilation time of deep water is shorter in the Sulu Sea than the SCS. The mean column inventory of C_ant in the Sulu Sea is 39 mol m^-2 (error range (ER): 30-49 mol m^-2) for the deeper part and the estimated total C_ant inventory in 2011 is 81 Tg (ER: 66-98 Tg). By applying the Transient Steady State approximation on the C_ant data we calculated the lower limit of the diapycnal diffusivity, K_z, to 1.1×10^-4 m² s^-1 (ER: 0.7-1.8×10^-4 m² s^-1) for the Sulu Sea below the surface mixed layer.