IMOS - SOOP Ocean Carbon Dioxide Data from RV Aurora Australis voyage AA1213V4 (Hobart-Hobart)

This data was collected in February - March 2013 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Aurora Australis (IMOS platform code: VNAA) voyage AA1213V4.\n\nDeparted: \tHobart, Tasmania, February 28, 2013\nArrived: Hobart, Tasmania, March 14, 2013\n\nCO2 System Overview:\nThe fugacity of carbon dioxide (fCO2) in surface seawater was measured using a General Oceanics Inc. automated system (Model 8050; Pierrot et al 2009). Seawater is sprayed into an equilibration chamber and CO2 in the headspace gas equilibrates with the seawater. The headspace gas is pumped through a thermoelectric condenser followed by a nafion drying tube before flowing through a Licor 7000 non-dispersive infrared gas analyser used to measure the CO2 mole fraction (XCO2) of the dried air. The gas flow is stopped temporarily for the CO2 measurements, which are made at atmospheric pressure. A set of four CO2 standards that cover the range of CO2 values expected in the ocean are analysed about every three hours to calibrate the gas analyser. Atmospheric XCO2 (dry) is measured after the standards by pumping clean outside air from an intake on the forward mast of the ship. \n\nSeawater intake and ancillary data:\nThe seawater intake is at about 6 m depth. A remote temperature sensor (Seabird Electronics SBE38) located at the intake is used to measure sea surface temperature (SST). Sea surface salinity is measured using a thermosalinograph (Seabird Electronics SBE21) mounted in the oceanographic lab next to the pCO2 system. The travel time between the intake and CO2 system is typically about 70 seconds with warming usually less than 0.7ºC in cold waters near freezing. The thermosalinograph water is from the same intake and supply line. \n\nMeteorological data, salinity, SST, and ships position and time are taken from the ship’s logging system.

本数据集由海洋综合观测系统（Integrated Marine Observing System，IMOS）船舶走航式CO₂测量研究小组，于执行航次AA1213V4的“极光南方号”（RV Aurora Australis）科考船上完成采集，该船的IMOS平台代码为VNAA，数据采集时间为2013年2月至3月。

起航地点：塔斯马尼亚州霍巴特，2013年2月28日
返航地点：塔斯马尼亚州霍巴特，2013年3月14日

CO₂系统概述：
表层海水二氧化碳逸度（fCO₂）的测量采用通用海洋学公司（General Oceanics Inc.）的自动化系统（型号8050；Pierrot等，2009年）。具体流程为：将海水喷入平衡舱，顶空气体中的CO₂与海水达到气液平衡；顶空气体经热电冷凝器后，再通过纳菲隆干燥管进行干燥，随后流入Licor 7000型非色散红外气体分析仪，以测定干燥空气中的CO₂摩尔分数（XCO₂）。CO₂测量过程中会暂时停止气流，且所有测量均在大气压下完成。每约3小时分析一组覆盖海洋中预期CO₂浓度范围的4种CO₂标准气体，用于校准气体分析仪。完成标准气体校准后，通过船舶前桅的进气口抽取清洁外部空气，以测定大气干燥态XCO₂。

海水取水口及辅助观测数据：
海水取水口位于约6米水深处。取水口处安装有西贝尔电子（Sea-Bird Electronics）SBE38型远程温度传感器，用于测量海表温度（SST）。海表盐度通过安装在海洋学实验室中、毗邻pCO₂系统的西贝尔电子SBE21型热盐深仪测得。取水口至CO₂系统的输水耗时通常约70秒，在接近冰点的冷水中，输水过程中水温升高通常低于0.7℃。热盐深仪的取水水源与CO₂系统取自同一取水口及输水管道。

气象数据、盐度、海表温度、船舶位置及时间信息均来自船舶日志系统。