Air sampling for greenhouse gas concentrations and associated species, 1984-2006

This dataset was originally set up as a "State of the Environment" indicator - however, that application no longer functions at the Australian Antarctic Data Centre, so the data have been extracted and attached to this original metadata record for the indicator.INDICATOR DEFINITIONMeasurement of air samples for values of the primary greenhouse gases (carbon dioxide, methane and nitrous oxide) and associated species (carbon monoxide, hydrogen and isotopes of carbon dioxide) in the Southern Hemisphere atmosphere.RATIONALE FOR INDICATOR SELECTIONOver the last century the concentration of greenhouse gases has risen in the atmosphere. The average rise is about half that expected from human activities, predominantly the burning of fossil fuel. Thus observations of the concentration of these gases provides a measure of anthropogenic greenhouse forcing in the atmosphere, and for example, monitors the effectiveness of oceans and terrestrial biomes in removing the excess CO2.Measurements of long-lived trace gas levels in Antarctic air generally provide an accurate integration of global exchanges between the surface and the atmosphere. The climate-influencing gases of main interest are gases released as a result of human activity, as well as from (climate-driven) physical, chemical and biological processes in both land and oceans. The Antarctic monitoring, in concert with other global network results, exploits trace gas ratios to identify and locate globally significant exchanges.DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAMSpatial Scale: High latitude Southern Hemisphere air samples are collected from AAD sites by BoM personnel at Mawson station, Casey station and Macquarie Island, and by NOAA staff at South Pole. These complement CSIRO supervised sites at Cape Grim, Tasmania and ~7 other globally distributed locations.Frequency: Typical sites collect ~4 flasks of air per month for subsequent analysis at CSIRO.Measurement Technique: Various chemical analysis techniques (Francey et al. 1996).RESEARCH ISSUESFor global trace gas monitoring, improvements are sought in network intercalibration and in increased sampling, e.g. continuous CO2 monitoring, vertical profiles, continental sites. More generally, improved coordination of atmospheric composition modeling, surface flux measurements and atmospheric transport representations are sought to serve new 'multiple-constraint modeling frameworks'.LINKS TO OTHER INDICATORSMonthly averages of daily maximum and minimum temperatures for Australian Antarctic StationsMean sea level Average Summer chlorophyll concentrations in the Southern Ocean, from latitude bands 40-50 deg S, 50-60 deg S, 60 deg S-continentAverage sea surface temperatures in latitude bands 40-50 deg S, 50-60 deg S, 60 deg S-continentAntarctic sea ice extent and concentration

本数据集最初被设立为"环境状况"（State of the Environment）指标——但该指标应用在澳大利亚南极数据中心（Australian Antarctic Data Centre, AADC）已无法运行，因此相关数据已被提取并附至该指标的原始元数据记录中。

指标定义：对南半球大气中的主要温室气体（二氧化碳、甲烷和一氧化二氮）及相关组分（一氧化碳、氢气及二氧化碳同位素）的空气样本开展检测分析。

指标选取依据：近一个世纪以来，大气中温室气体浓度持续攀升。实际平均增幅约为人类活动（主要为化石燃料燃烧）预期增幅的一半。因此，对上述气体浓度的观测可用于量化大气中的人为温室强迫效应，例如可监测海洋与陆地生物群系清除过量二氧化碳的效率。南极大气中长寿命痕量气体的浓度测量结果，通常可精准整合地表与大气之间的全球气体交换过程。本研究重点关注的影响气候的气体，既包括人类活动排放的气体，也涵盖陆地与海洋中（气候驱动的）物理、化学及生物过程产生的气体。南极监测网络与其他全球监测网络的结果相结合，可通过痕量气体比值来识别并定位具有全球重要性的气体交换事件。

指标监测方案的设计与策略：
空间范围：南半球高纬度地区的空气样本采集工作由澳大利亚气象局（Bureau of Meteorology, BoM）人员在莫森站、凯西站和麦夸里岛的AADC站点开展，美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）人员则在南极点进行采样。上述采样站点可补充澳大利亚联邦科学与工业研究组织（Commonwealth Scientific and Industrial Research Organisation, CSIRO）监管的塔斯马尼亚州格雷姆角及其他约7个全球分布站点的采样数据。
采样频率：常规站点每月采集约4瓶空气样本，送至CSIRO进行后续分析。
测量技术：采用多种化学分析技术（Francey等，1996）。

研究议题：针对全球痕量气体监测，当前亟需优化监测网络的互校准工作，并扩大采样规模，例如开展连续二氧化碳监测、垂直剖面采样以及大陆站点采样。更广泛而言，为支撑新型"多约束建模框架"，亟需加强大气成分模拟、地表通量测量与大气传输表征三者之间的协同联动。

与其他指标的关联：
澳大利亚南极站每日最高、最低气温的月平均值；
平均海平面；
南大洋40°S-50°S、50°S-60°S及60°S至南极大陆各纬度带的夏季平均叶绿素浓度；
上述纬度带的平均海表温度；
南极海冰范围与浓度。