瓦里关气相色谱法大气CO_2和CH_4在线观测数据处理分析

加强我国本底站温室气体数据资源的科学管理与共享,首先应保证观测全流程的标准化和规范化,确立数据处理和质量控制方法.我国青海瓦里关全球本底站自1994年开始了气相色谱-氢火焰离子化检测器法(GC-FID)大气CO2和CH4在线观测,本文详细讨论了该系统原始资料采集、数据信息合并、时间序列检查、观测员级质量控制和专家级质量控制等流程.利用局部近似回归法对大气CO2和CH4数据进行本底值筛分,获得CO2本底数据百分比约占有效数据的72%、CH4占44%.在线观测的CO2和CH4月平均浓度与同期瓶采样分析结果基本一致,相对偏差均在±0.5%以内.经流程化处理和质控的瓦里关大气CO2和CH4本底浓度变化资料已进入全球同化数据库(Globalview-CO2、Globalview-CH4),报送世界温室气体数据中心(WDCGG)并应用于世界气象组织(WMO)温室气体公报和联合国政府间气候变化专门委员会(IPCC)评估.

Data Processing and QA/QC of Atmosphere CO2 and CH4 Concentrations by a Method of GC-FID in-situ Measurement at Waliguan Station

To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of observations and establish the data treatment and quality control procedure so as to maintain consistency in atmospheric carbon dioxide (CO₂) and methane (CH₄) measurements from different background stations. An automated gas chromatographic system (Hewlett Packard 5890GC employing flame ionization detection) for in situmeasurements of atmospheric CO₂ and CH₄ has been developed since 1994 at the China Global Atmosphere Watch Baseline Observatory at Mt. Waliguan, in Qinhai. In this study, processing and quality control flow of CO₂ and CH₄ data acquired by HP ChemStation are discussed in detail, including raw data acquisition, data merge, time series inspection, operator flag, principal investigator flag, and the comparison of the GC measurement with the flask method. Atmosphere CO₂ and CH₄ mixing ratios were separated as background and non-background data using a robust local regression method, approximately 72% and 44% observed values had been filtered as background data for CO₂ and CH₄, respectively. Comparison of the CO₂ and CH₄ in situdata to the flask sampling data were in good agreement, the relative deviations are within±0.5% for CO₂ and for CH₄. The data has been assimilated into global database(Globalview-CO₂, Globalview-CH₄), submitted to the World Data Centre for Greenhouse Gases (WDCGG), and applied to World Meteorological Organization (WMO) Greenhouse Gas Bulletin and assessment reports of the United Nations Intergovernmental Panel on Climate Change (IPCC).