摘要
地表气压对温室气体浓度反演具有非常重要的影响。利用地基便携式傅里叶变换光谱仪EM27/SUN观测了敦煌地区H2O,CO2,CH4及CO气体分子的浓度,获得了2018年6月27日到7月21日敦煌地区大气中XH2O,XCO2,XCH4及XCO的时间序列,结合敦煌观测数据,定量分析了地表气压对气体柱-平均摩尔分数Xgas(column-averaged dry air mole fractions, DMFs)反演的影响。结果表明:XH2O,XCO2,XCH4及XCO与地表气压密切相关,相关系数均高于0.99,柱总量随地表气压的变化快慢决定柱-平均摩尔分数随地表气压的变化趋势。相比较CO2,CH4及CO分子,XH2O对地表气压的敏感性较弱,地表气压改变1 hPa,XH2O,XCO2,XCH4及XCO分别变化0.027 8%,0.065 9%,0.068 6%和0.062%;观测期间,H2O,CO2的浓度变化幅度波动较大,XCH4,XCO变化较小,XH2O平均值在2 000×10-6~6 000×10-6变化,而XCO2平均值在407.27×10-6~417.60×10-6变化,敦煌站点XH2O,XCO2,XCH4及XCO的测量精度分别为2.3%,0.14%,0.12%及1.7%,XCO2及XCH4的测量精度均优于TCCON网的测量精度;与GOSAT卫星数据对比结果显示,地基反演的XCO2,XCH4值均偏大,XCO2的绝对偏差为7.07×10-6,XCH4的绝对偏差为0.025×10-6;与WACCM数据对比显示,地基反演XCO2结果多数大于WACCM值,最大绝对偏差可以达到8.0×10-6,地基反演XCH4值小于WACCM值,最大绝对偏差为0.032×10-6。实时观测数据更能反映当地的具体情况,研究结果可为我国温暖带干旱性气候温室气体源与汇的研究提供数据支撑和理论基础。
Surface pressure has a significant impact on the inversion of greenhouse gas concentrations. Observations of the column-averaged dry air mole fractions of water vapor, carbon dioxide, carbon monoxide, and methane in Dunhuang are presented based on ground-based Fourier transform infrared spectrometer(EM27/SUN). The time series of XH2O, XCO2, XCH4, and XCO from June 27 to July 21(2018) in Dunhuang were obtained, and the sensitivity of surface pressure to the column-averaged dry air mole fractions retrieval was analyzed. The main results are as follows: The surface pressure has a significant influence on the inversion results, and the underestimated surface pressure results in low inversion results. XH2O, XCO2, XCH4, and XCO are sensitive to changes in surface pressure, and their correlation coefficients with surface pressure are higher than 0.99. The change in the total column volume with surface pressure determines the trend of column-average mole fraction with surface pressure. Compared with CO2, CH4, and CO molecules, XH2O is less sensitive to surface pressure. When the local pressure is changed by 1 hPa, ΔXH2O, ΔXCO2, ΔXCH4 and ΔXCO are 0.027 8%, 0.065 9%, 0.068 6%, and 0.062%, respectively. The daily averages variation range of XH2O and XCO2 are 2 000×10-6-6 000×10-6 and 407.27×10-6-417.60×10-6, respectively. The measurement accuracies of XH2O, XCO2, XCH4, and XCO at Dunhuang site are 2.3%, 0.14%, 0.12%, and 1.7%, respectively. The measurement accuracies of XCO2 and XCH4 are within the requirement of TCCON. Comparing daily averaged XCO2 and XCH4 based on EM27/SUN with GOSAT, the results show that the value of XCO2 and XCH4 based on GOSAT satellite data are lower than our observations, and deviations of 7.07(XCO2) and 0.025×10-6(XCH4). The value of XCO2 based on WACCM data are lower than our observations with a deviation of 8×10-6 while the value of XCH4 based on WACCM data are higher than our observations with a deviation of 0.032×10-6, indicating that WACCM data does not reflect the invasion of foreign sources. These results provide a theoretical basis and first-hand observation data to understand the space-time distribution and changes of greenhouse gases in Dunhuang, China.
作者
刘丹丹
黄印博
孙宇松
卢兴吉
曹振松
LIU Dan-dan;HUANG Yin-bo;SUN Yu-song;LU Xing-ji;CAO Zhen-song(Key Laboratory of Atmospheric Optics,Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch of Graduate School,University of Science and Technology of China,Hefei 230026,China;College of Electrical and Optoelectronic Engineering,West Anhui University,Luan 237012,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2020年第3期573-583,共11页
Optics and Precision Engineering
基金
中国科学院战略性先导科技专项(A类)资助项目(No.XDA17010104)。
关键词
傅里叶变换光谱技术
温室气体
分子摩尔分数
GOSAT
地表气压
Fourier transform infrared spectroscopy
greenhouse gases
Dry air Mole Fractions(DMFs)
satellite data
surface pressure
