pCO2 Data — Survey CE18007 INFOMAR Seabed Mapping

pCO2 is the partial pressure of CO2 in a liquid or gas. In oceanography, it is used to investigate carbon dioxide (CO2) dissolved in the surface layers of the ocean in order to better understand changes in ocean carbon chemistry and ocean acidification due to enhanced atmospheric CO2. The RV Celtic Explorer has a pCO2 Underway System. pCO2 data was collected as part of the CE18007 INFOMAR Seabed Mapping survey of the Celtic Sea on board the RV Celtic Explorer in April"May 2018. Instrument information: - SST (± 0.001 deg C): SST was measured with a thermosalinograph from Seabird (SBE21) with an external SBE38 which was installed close to the seawater intake. Both instruments were calibrated approximately every 12 months. -Equilibrator temp (±0.05 °C): Equilibrator temperature is measured by a Fluke Hart 1523, wich is known to be stable over a longer period. It was calibrated in 2016. -SSS (± 0.5 PSU): SSS was measured with a thermosalinograph from Seabird (SBE21) which was calibrated approximately every 12 months. -Atmospheric press. (± 0.1 mbar): Atmospheric pressure was measured using a Druck barometer with a precision of 0.2%. The sensor is installed at approximately 5m height and pressure is corrected to sea level. -Equilibrator press (± 2 mbar): The equilibrator is open to the atmosphere. Since no absolute pressure sensor was installed the pressure from the atmospheric pressure sensor was used. A SETRA difference pressure sensor is attached to the equilibrator. -pCO2"fCO2 (±2µatm): Accuracy of pCO2"fCO2 data was recalculated to be better than 2 µatm. IR sensor: Licor 7000, calibrated with 3 non-zero standard gases. Standard gases: Manufactued - Air Products, Calibrated - Mace Head Research Station (198.29 399.28 606.52]) Water flow rate: 2-3 L min-1 Gas flow rate: 80 - 220 mL min-1 (equilibrator gas flow was 220 mL min-1) A General Oceanics pCO2 system (model 8050) was used for pCO2 measurements. The system is described in detail in Pierrot et al.(2009). Surface water is pumped continuously from the intake to the equilibrator. The equilibrator contains a water spray head, and as the water flows through it the dissolved CO2 equilibrates with the headspace. The headspace is dried and xCO2 is determined by an infrared sensor. Calculations were performed following Pierrot (2009) and are described in detail in Steinhoff (2010). Collect pC02 data (partial pressure of CO2 in a liquid or gas) to investigate carbon dioxide (CO2) dissolved in the surface layers of the ocean which contributes towards our understand of changes in ocean carbon chemistry and ocean acidification due to enhanced atmospheric CO2.二氧化碳分压（pCO₂，partial pressure of CO₂）指液体或气体中的二氧化碳分压。在海洋学研究中，该指标被用于探究海洋表层溶解的二氧化碳（CO₂），以期更深入理解因大气CO₂浓度升高引发的海洋碳化学变化与海洋酸化现象。 "RV Celtic Explorer"（凯尔特探险家号）搭载了走航式pCO₂观测系统。本次pCO₂数据采集工作，是2018年4月至5月期间在"RV Celtic Explorer"上开展的CE18007 INFOMAR凯尔特海海底测绘航次的组成部分。 仪器信息： - 海表温度（Sea Surface Temperature，SST，±0.001 ℃）：采用海鸟公司（Seabird）的SBE21型流动式温盐计进行测量，配套安装了靠近海水取水口的SBE38外置传感器。两台仪器每约12个月校准一次。 - 平衡器温度（±0.05 ℃）：由福禄克哈特1523型（Fluke Hart 1523）设备测量，该设备长期稳定性优异，校准工作于2016年完成。 - 海表盐度（Sea Surface Salinity，SSS，±0.5 PSU）：采用海鸟公司（Seabird）的SBE21型流动式温盐计进行测量，每约12个月校准一次。 - 大气压力（±0.1 mbar）：采用Druck品牌气压计测量，精度为0.2%。该传感器安装于约5米高度，测量压力需修正至海平面标准大气压。 - 平衡器压力（±2 mbar）：平衡器与大气相通，因未安装绝对压力传感器，故采用大气压力传感器的读数。系统配备了Setra差压传感器。 - pCO₂/fCO₂（±2 µatm）：经重新计算，pCO₂/fCO₂数据的精度优于2 µatm。 - 红外传感器：采用Licor 7000型，使用3种非零点标准气体进行校准。 - 标准气体：由空气产品公司（Air Products）生产，校准工作由梅斯黑德研究站（Mace Head Research Station）完成，校准值分别为198.29、399.28、606.52 µatm。 - 水流速率：2~3 L min⁻¹ - 气体流速：80~220 mL min⁻¹（平衡器气体流速为220 mL min⁻¹） 本次pCO₂测量采用通用海洋学家公司（General Oceanics）的pCO₂系统（型号8050），该系统的详细说明参见Pierrot等人（2009年）的研究成果。表层海水通过取水口连续泵送至平衡器，平衡器内置喷水头，水流经喷水头时，溶解的CO₂与顶空气体达到气液平衡。顶空气体经干燥处理后，通过红外传感器测定xCO₂。计算过程遵循Pierrot（2009年）的方法，详细步骤参见Steinhoff（2010年）的研究。 本数据集采集pCO₂数据（即液体或气体中的二氧化碳分压），以探究海洋表层溶解的二氧化碳，助力我们理解因大气CO₂浓度升高引发的海洋碳化学变化与海洋酸化现象。