Cape Grim Baseline Air Pollution Station - Atmospheric CO2 Measurements 1976- 2004

The CSIRO archive of observed atmospheric CO2 concentrations at the Cape Grim Baseline Air Pollution Station in North-West Tasmania for the period 1976 until 2004. Measurements of atmospheric CO2 levels began in 1976 and have continued until the present day, giving an unprecedented view of the overall change in CO2 composition over the 30+ year time-frame. These started with the URAS-2T instrument until Jun 1990, continuing with the Siemens Ultramat 5E system until July 2004, followed by the LOFLO Mk2 instrument until the present day. All use NDIR (non-dispersive infrared) analysis techniques with LOFLO being CSIRO developed to make measurements consuming smaller volumes of calibration gas, requiring less operator intervention and having less bias than traditional NDIR measurement techniques. Logged data is available in a single ascii text file in hourly averaged periods containing CO2 concentration, wind speed and direction, a baseline and quality flag. Conditions are considered baseline when wind directions are between 190 & 280° bringing air from the southern ocean. The file size for the given variables is approximately 400 KB for an hourly averaged year of data, with the period from 1976-2004 being approx 11.0 MB.澳大利亚联邦科学与工业研究组织（Commonwealth Scientific and Industrial Research Organisation, CSIRO）收藏的塔斯马尼亚州西北部格里姆角（Cape Grim）基准空气污染观测站的大气二氧化碳浓度观测档案，观测时段为1976年至2004年。该站的大气二氧化碳浓度观测始于1976年，并持续至今，为我们提供了30余年时间尺度上二氧化碳组分整体变化的前所未有的观测视角。观测初期使用URAS-2T仪器至1990年6月，随后改用西门子（Siemens）Ultramat 5E系统直至2004年7月，之后则采用LOFLO Mk2仪器并沿用至今。所有仪器均采用非色散红外（non-dispersive infrared, NDIR）分析技术，其中LOFLO Mk2为CSIRO自主研发，相较于传统NDIR测量技术，该仪器可消耗更少体积的校准气、减少人工干预并降低测量偏差。已记录的观测数据以单一ASCII文本文件形式存储，数据为逐小时平均值，包含二氧化碳浓度、风速、风向、基准值以及质量标记。当风向处于190°至280°区间、气流源自南大洋时，观测条件被认定为基准状态。单一年份的逐小时平均数据文件大小约为400 KB，而1976年至2004年完整时段的数据集文件大小约为11.0 MB。