Collaborative Research: Surface pCO2 and the effects of Winter Time Overturning in the Drake Passage

拟议的项目将扩大观测套件，并延长R/VIB L.M.上德雷克海峡正在进行的表面溶解二氧化碳（pCO 2）测量断面的现有时间序列。古尔德 其他观测包括氧气、营养物和总CO2（TCO 2）浓度，以及TCO 2的13 C与12 C比率。 持续和扩大的时间序列将有助于实现两个主要科学目标：量化德雷克海峡四个主要水团状况中表层二氧化碳种类的空间和时间变异性和趋势，以及了解导致德雷克海峡表层二氧化碳分压变化和由此产生的海气二氧化碳通量的主要过程和这些过程的变化。 扩大后的方案还将包括对TCO 2的14 C/12 C的分析和对一次短期冬季巡航观测结果的具体研究，目的是检验德雷克海峡表层沃茨中溶解的二氧化碳是由冬季混合程度决定的这一假设。鉴于现在和将来可能影响南大洋深水通风的两种情况，这一点具有特别重要的意义：随着纬向风的增加，水柱分层减少，或者由于降水量增加和气候变化引起的变暖而增加分层。如果冬季混合决定了德雷克海峡的年平均pCO 2，那么大气pCO 2的增加趋势对海面pCO 2的影响应该很小。

The proposed project will expand the suite of observations and lengthen the existing time series of underway surface dissolved carbon dioxide (pCO2) measurements transects across the Drake Passage on the R/VIB L.M. Gould. The additional observations include oxygen, nutrients and total CO2 (TCO2) concentrations, and the 13C to 12C ratio of TCO2. The continued and expanded time series will contribute towards two main scientific goals: the quantification of the spatial and temporal variability and the trends of surface carbon dioxide species in four major water mass regimes in the Drake Passage, and the understanding of the dominant processes and changes in those processes that contribute to the variability in surface pCO2 and the resulting air-sea flux of CO2 in the Drake Passage. The expanded program will also include the analysis of the 14C/12C of TCO2 and the specific study of the observations on one short wintertime cruise, with the objective of testing the hypothesis that the dissolved carbon dioxide in surface waters of the Drake Passage is determined by the degree of winter mixing. This is of special significance in light of two scenarios that may be affecting the ventilation of Southern Ocean deep water now and in the future: a decrease in water column stratification with the observations of higher zonal winds, or an increase in stratification due to higher precipitation and warming from climate change. If winter mixing determines the mean annual pCO2 in the Drake Passage, the increasing trend in atmospheric pCO2 should have little effect on sea surface pCO2.