Spectroscopic measurements of tropospheric CO, C₂H₆, C₂H₂, and HCN in northern Japan

Abstract

Tropospheric column amounts and mixing ratios of CO, C2H6, C2H2, and HCN were retrieved from ground‐based infrared solar spectra using a vertical profile retrieval algorithm (SFIT2). 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 Japan from May 1995 to June 2000. 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, C2H6, and C2H2 and in summer (May–July) for HCN. Good correlations between CO, C2H6, and C2H2 indicated that they had similar sources and underwent similar dilution processes. Deviation of HCN relative to its seasonal mean value (ΔHCN) is correlated with the similar deviation of CO (ΔCO), indicating that enhancements of CO and HCN above the mean levels were probably due to the same sources. Linear trends in tropospheric CO, C2H6, and C2H2 from May 1995 to June 2000 (excluding 1998) were (−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 relatively small. Abnormally high tropospheric amounts of the four molecules were recorded in 1998. HCN amounts were found to be much higher than its seasonal mean value throughout 1998 with a 65% maximum increase in August 1998. Significant increases of CO, C2H6, and C2H2 took place in August–October 1998. Trajectory calculations, global fire maps, and satellite smoke images revealed that biomass burning in eastern Siberia from mid‐July to early October 1998 was the major cause of the elevated levels in tropospheric CO, C2H6, C2H2, and HCN observed in northern Japan in 1998.

Five years of CO, HCN, C<sub>2</sub>H<sub>6</sub>, C<sub>2</sub>H<sub>2</sub>, CH<sub>3</sub>OH, HCOOH and H<sub>2</sub>CO total columns measured in the Canadian high Arctic

“…The total columns of these three gases are greater in winter because their common sources, which are fossil fuel emissions, are usually enhanced in the dry and cold period (Zhao et al, 2002). In addition, these gases accumulate during this period because their main removal pathway is the reaction with OH, which does not take place in the dark.…”

“…The CO total columns are retrieved in three widely used MWs, including a weak line of CO at 2057.858 cm −1 , another weak line of CO at 2069.656 cm −1 and a strong line of CO at 2158.300 cm −1 (Notholt et al, 2000;Zhao et al, 2002). The use of a combination between weak and strong absorption lines increases the vertical sensitivity of the retrievals (Barret et al, 2003).…”

“…For HCN, two MWs, around 3287.248 cm −1 (Mahieu et al, 1997;Notholt et al, 2000;Zhao et al, 2002) and around 3268.200 cm −1 , are preferred over the three IRWG recommendations (which are 3268. 05-3268.40, 3287.10-3287.35 and 3299.40-3299.60 cm −1 ).…”

“…The sources of C 2 H 6 are natural gas and fossil fuel emissions (Singh and Zimmerman, 1992). C 2 H 2 main sources include natural gas, biofuel combustion products and biomass burning emissions (Gupta et al, 1998;Logan et al, 1981;Rudolph, 1995;Xiao et al, 2007;Zhao et al, 2002). CO, C 2 H 6 and C 2 H 2 are removed by oxidation via OH reaction (Logan et al, 1981), leading to atmospheric lifetimes of approximately fifty-two days (Daniel and Solomon, 1998), eighty days (Xiao et al, 2008) and two weeks in the atmosphere (Xiao et al, 2007), respectively.…”

“…CO, HCN, C 2 H 6 and C 2 H 2 total and partial columns have been measured by ground-based FTIR spectroscopy at several locations in the Northern Hemisphere (Mahieu et al, 1997;Rinsland et al, , 2000Zhao et al, 2002) and in the Southern Hemisphere (Rinsland et al, 1999(Rinsland et al, , 2001Paton-Walsh et al, 2010;Vigouroux et al, 2012). CH 3 OH and HCOOH have been measured in a limited number of ground-based FTIR studies (Paton-Walsh et al, 2005Rinsland et al, , 2009Zander et al, 2010;Paulot et al, 2011).…”