Observations of tropospheric trace gases by ground-based high resolution FT-IR spectrometer

利用地面红外太阳光谱反演了对流层一氧化碳（CO）、乙烷（C_2H_6）、乙炔（C_2H_2）和氰化氢（HCN）的柱量和混合比。在Moshiri用高光谱分辨率傅里叶变换红外（FTIR）光谱仪记录光谱（44.4°N）和陆别反演结果表明，日本北方对流层中四种分子的含量存在明显的季节变化，在冬春季达到最大值在观测期间，对流层中偶尔观测到这4种分子浓度的同时增强，这可能是由于同一来源引起的。对流层中CO、C_2H_6和C_2H_2的浓度具有很好的相关性，表明它们有相似的来源和稀释过程。轨迹计算和全球火灾图显示，亚洲大陆生物量燃烧的排放物向东输送到日本北方。1995年5月至2000年6月，对流层CO、C2 H6和C2 H2的年下降趋势分别为（-2.10 <$0.30）、（-2.53 <$0.30）和（-3.99 <$0.57）%，而HCN的年下降趋势不明显。由于平流层O_3对太阳紫外辐射的吸收，20世纪80年代中期以来全球平流层O_3的减少导致了地表太阳紫外辐射的增加。日本北方对流层CO、C_2H_6和C_2H_2浓度呈负趋势的原因可能是由于太阳紫外辐射通过与OH的光化学反应而增加。此外，过去10年来生物质燃烧和人为源排放的减少可能是对流层CO、C_2H_6和C_2H_2浓度呈下降趋势的另一个原因。1995年5月至2000年6月在日本北方观测到的C_2H_2。

Tropospheric column amounts and mixing ratios of carbon monoxide (CO), ethane (C_2H_6), acetylene (C_2H_2), and hydrogen cyanide (HCN) were retrieved from ground-based infrared solar spectra. The spectra were recorded with high spectral resolution Fourier Transform Infrared (FTIR) spectrometers at Moshiri (44.4°N) and Rikubetsu (43.5°N) in northern.The retrievals show significant seasonal variations in the tropospheric content of the four molecules over northern Japan with maxima in winter-spring (February-April) for CO, C_2H_6 and C_2H_2 and in summer (May-July) for HCN.Simultaneous enhancements of the tropospheric concentration of the four molecules were occasionally observed during the observational period, possibly due to the same sources. Good correlations among the tropospheric amounts of CO, C_2H_6, and C_2H_2 indicated that they had similar sources and underwent similar processes of dilution. Trajectory calculations and global fire maps revealed that emissions of biomass burning on the Asian continent were transported eastward to northern Japan. Decreasing trends in tropospheric CO, C_2H_6, and C_2H_2 from May 1995 to June 2000 were found to be (-2.10±0.30), (-2.53±0.30), and (-3.99±0.57)%yr, respectively, while the trend of (-0.93±0.49)%/yr in HCN was not significant. Since stratospheric O_3 absorbs the solar UV radiation, the depletion of global stratospheric O_3 since mid-1980s resulted in an increase of the solar UV radiation on the earth surface. It is appear that the observed negative trends in tropospheric CO, C_2H_6, and C_2H_2 over northern Japan should be due to the increase in the solar UV radiation through the photochemical reactions with OH.In addition, reduced emissions of these gases from biomass burning and anthropogenic sources in the past decade would be another reason for the decreasing trends in troposphericCO, C_2H_6, and C_2H_2 observed in northern Japan from May 1995 to June 2000.