Measurements of ozone-depleting substances at the Cape Verde Observatory

该项目将扩大我们在佛得角天文台（CVO）的大气卤碳气相色谱-质谱测量，以包括更广泛的现有和新出现的消耗臭氧物质。该学生还将在佛得角收集新的空气和海水VSLS氯测量值，以调查和参数化现场海洋生产。该学生将测试并协调与其他小组使用的柱组合，以便比较新卤代烃物种的相对保留时间，通过相互比较程序为CVO以前未测量过的化合物建立校准刻度，并建立一个每月在CVO逆风海水采样程序，通过吹扫和捕集气相色谱-质谱法测量CH2Cl2， CHCl3和其他主要是天然的VSLS。同时分析海水中CFC-11的浓度，可以计算过量的CH2Cl2和CHCl3的“饱和异常”，这是评估海洋是否正在发生原位生产所必需的。这些饱和度异常将分析与叶绿素- a、有色溶解有机物质和溶解有机碳丰度等相关的模式和趋势，以便将这些排放扩大到热带海洋。因此，该项目将确定新出现的人为消耗臭氧物质的形态和趋势，并更好地限制《蒙特利尔议定书》未管制的短寿命消耗臭氧化合物的自然排放。

This project will expand our atmospheric halocarbon GC-MS measurements at the Cape Verde Observatory (CVO) to include a wider range of established and emerging ozone depleting substances. The student will also collect new air and seawater VSLS chlorine measurements at Cape Verde to investigate and parametrise in situ ocean production. The student will test and harmonise column combinations with those used by other groups to allow comparison of relative retention times for new halocarbon species, establish calibration scales for compounds not previously measured at CVO via an intercomparison programme, and establish a program of monthly seawater sampling upwind of the CVO for measurements of CH2Cl2, CHCl3 and other, predominantly natural, VSLS by purge and trap GC-MS. Simultaneous analysis of CFC-11 concentrations in seawater will allow calculation of the excess CH2Cl2 and CHCl3 "saturation anomalies", required to assess whether in-situ oceanic production is occurring. These saturation anomalies will be analysed for patterns and trends that correlate with, for example, chlorophyl-A, coloured dissolved organic material and dissolved organic carbon abundances, to allow scale-up of these emissions to the tropical ocean. Thus, the project will determine patterns and trends in emerging anthropogenic ozone depleting substances and better constrain natural emissions of short-lived ozone depleting compounds not controlled under the Montreal Protocol.