Processed CO2/O2 Float data from 4 deployments near Cape Verde Island (11/2010 - 06/2011)

In recent years, profiling floats, which form the basis of the successful international Argo observatory, are also being considered as platforms for marine biogeochemical research. This study showcases the utility of floats as a novel tool for combined gas measurements of CO2 partial pressure (pCO2) and O2. These float prototypes were equipped with a small-sized and submersible pCO2 sensor and an optode O2 sensor for highresolution measurements in the surface ocean layer. Four consecutive deployments were carried out during November 2010 and June 2011 near the Cape Verde Ocean Observatory (CVOO) in the eastern tropical North Atlantic. The profiling float performed upcasts every 31 h while measuring pCO2, O2, salinity, temperature, and hydrostatic pressure in the upper 200 m of the water column. To maintain accuracy, regular pCO2 sensor zeroings at depth and surface, as well as optode measurements in air, were performed for each profile. Through the application of data processing procedures (e.g., time-lag correction), accuracies of floatborne pCO2 measurements were greatly improved (10-15 µatm for the water column and 5 µatm for surface measurements). O2 measurements yielded an accuracy of 2 µmol/kg. First results of this pilot study show the possibility of using profiling floats as a platform for detailed and unattended observations of the marine carbon and oxygen cycle dynamics.

近年来，作为成熟的国际Argo观测网（Argo observatory）核心载体的剖面浮标（profiling float），也被视作海洋生物地球化学研究的新型观测平台。本研究论证了浮标作为新型工具，可同步开展二氧化碳分压（pCO₂）与氧气（O₂）的联合气体测量。该浮标原型搭载了小型可潜式pCO₂传感器与光学溶解氧传感器（optode O₂ sensor），用于表层海洋的高分辨率观测。2010年11月至2011年6月期间，研究团队在热带北大西洋东部的佛得角海洋观测站（Cape Verde Ocean Observatory, CVOO）附近完成了4次连续布放。该剖面浮标每31小时完成一次剖面上浮，在此过程中采集水体上层200米内的pCO₂、O₂、盐度、温度与静压力数据。为保障测量精度，每次剖面观测均需在深水与表层对pCO₂传感器进行零点校准，并在空气中完成光学溶解氧传感器的标定。通过应用数据处理流程（如时间延迟校正），浮载式pCO₂测量的精度得到显著提升：水体测量精度可达10~15微大气压（µatm），表层测量精度可达5微大气压。氧气测量的精度可达2微摩尔每千克（µmol/kg）。本先导性研究的初步结果证实，剖面浮标可作为观测平台，实现海洋碳氧循环动态的精细化、无人值守观测。