Comparison of the regional CO2 mole fraction filtering approaches at a WMO/GAW regional station in China
Comparison of the regional CO2 mole fraction filtering approaches at a WMO/GAW regional station in China
复制标题
中国 WMO/GAW 区域站区域 CO2 摩尔分数过滤方法比较
DOI：
10.5194/amt-8-5301-2015
复制
发表时间：
2015-01-01
影响因子：
3.8
通讯作者：
Luan, T.
中科院分区：
文献类型：
--
作者：
Fang, S. X.;Tans, P. P.;Luan, T.
确定受当地排放/清除影响最小的大气二氧化碳观测数据对于趋势分析、区域源和汇的估计以及二氧化碳远距离传输建模至关重要。本研究采用四种方法对中国某世界气象组织/全球大气监视网（WMO/GAW）区域站（临安）2009年至2011年的大气CO2观测记录进行筛选。这些方法基于大气黑碳 (BC) 浓度、统计方法（基线信号的稳健提取，REBS）、CH4 作为辅助示踪剂 (AUX) 以及气象参数 (MET)。所有方法都能很好地捕获 LAN 的季节性二氧化碳循环。在平均区域摩尔分数中观察到差异，REBS 方法中的年度值至少比其他方法高 1.7 +/- 0.2 ppm。 BC方法可能会低估冬春季节区域CO2摩尔分数，应谨慎对待。 REBS 方法是一种纯粹的统计方法，它还可能会给区域 CO2 摩尔分数评估带来误差，因为过滤的趋势可能会受到“嘈杂”原始数据系列的影响。尽管 LAN 中 CH4 和 CO2 摩尔分数之间存在相关性，但不同的源/汇状态可能会给 AUX 方法中的区域 CO2 估计带来偏差，通常是在夏季。总体而言，MET方法似乎是最有利的，因为它主要关注当地潜在源汇的影响，并考虑昼夜变化和气象条件。使用MET方法，确定2009年至2011年LAN区域二氧化碳年增长率为3.1 +/- 0.01 ppm yr(-1)（标准误差）。
The identification of atmospheric CO2 observation data which are minimally influenced by very local emissions/removals is essential for trend analysis, for the estimation of regional sources and sinks, and for the modeling of long-range transport of CO2. In this study, four approaches are used to filter the atmospheric CO2 observation records from 2009 to 2011 at one World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station (Lin'an, LAN) in China. The methods are based on the concentration of atmospheric black carbon (BC), on a statistical approach (robust extraction of baseline signal, REBS), on CH4 as an auxiliary tracer (AUX), and on meteorological parameters (MET). All approaches do suitably well to capture the seasonal CO2 cycle at LAN. Differences are observed in the average regional mole fractions with annual values in the REBS method at least 1.7 +/- 0.2 ppm higher than the other methods. The BC method may underestimate the regional CO2 mole fractions during the winter-spring period and should be treated with caution. The REBS method is a purely statistical method and it may also introduce errors on the regional CO2 mole fraction evaluations, as the filtered trend may be influenced by the "noisy" raw data series. Although there are correlations between CH4 and CO2 mole fractions at LAN, the different source/sink regimes may introduce bias on the regional CO2 estimation in the AUX method, typically in summer. Overall, the MET method seems to be the most favorable because it mainly focuses on the influence of potential local sources and sinks, and considers diurnal variations and meteorological conditions. Using the MET method, the annual growth rate of regional CO2 at LAN is determined to be 3.1 +/- 0.01 ppm yr(-1) (standard error) from 2009 to 2011.