IMOS - SOOP Ocean Carbon Dioxide Data from RV Aurora Australis voyage AA1112V1 (Hobart-Hobart)

This data was collected in July/August 2011 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Aurora Australis (IMOS platform code: VNAA) voyage AA1112V1.

Departed: Hobart, Tasmania, July 19, 2011
Arrived: Hobart, Tasmania, August 05, 2011

CO2 System Overview:
The 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.

Seawater intake and ancillary data:
The 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.

Meteorological data, salinity, SST, and ships position and time are taken from the ship’s logging system.

本数据集由综合海洋观测系统（Integrated Marine Observing System，IMOS）机遇船舶走航CO₂测量研究小组，于2011年7月至8月期间在"极光南极号"科考船（RV Aurora Australis，IMOS平台代码：VNAA）的AA1112V1航次中采集完成。

启航：塔斯马尼亚州霍巴特港，2011年7月19日
抵达：塔斯马尼亚州霍巴特港，2011年8月5日

二氧化碳测量系统概况：
本研究采用通用海洋设备公司（General Oceanics Inc.）型号为8050的自动化系统（Pierrot等，2009），对表层海水二氧化碳分压（fCO₂）进行测定。具体测定流程如下：将海水喷入平衡舱，使顶空气体中的二氧化碳与海水达到气液平衡；随后将顶空气体泵送至热电冷凝器，经纳菲恩干燥管除湿后，流经Licor 7000型非分散红外气体分析仪（non-dispersive infrared gas analyser），以测量干燥空气的二氧化碳摩尔分数（XCO₂）。测量过程将暂时暂停气体流动，在大气压条件下完成CO₂浓度测定。每间隔约3小时，会使用一套覆盖海洋预期CO₂浓度范围的4组标准CO₂气体对气体分析仪进行校准。完成标准气体校准后，通过船舶前桅的进气口抽取清洁室外空气，以测定大气干燥态XCO₂。

海水取水与辅助观测数据：
海水取水深度约为6米。取水口处安装有Seabird Electronics SBE38型远程温度传感器，用于测量海表温度（Sea Surface Temperature，简称SST）。紧邻pCO₂测量系统的海洋学实验室中，搭载了Seabird Electronics SBE21型热盐计（thermosalinograph），用于测定海表盐度。取水口至CO₂测量系统的输水时长通常约70秒，在接近冰点的冷水域中，输水过程中的水温升高通常低于0.7℃。热盐计的取水水源与CO₂测量系统取自同一取水口及输水管道。

气象数据、盐度、海表温度、船舶位置与时间信息均取自船舶自带的日志系统。