Variations of carbon monoxide, methane, and water vapor in the total atmospheric column over Russia (Zvenigorod Station) between 1970 and 1999

The increase in the climate active gases content in the atmosphere is one of the reasons of the climate variations. Systematic spectroscopic measurements of CO, CH4 and H2O were carried out at Zvenigorod station of the Institute of Atmospheric Physics (IAP) RAN as well as in expeditions, including, Arctic and Antarctic daring last 30 years (Yurganov et al. 1995, 1997, Golitsyn et al 1991). All CO, CH4, and H2O spectroscopic measurements analysed in this paper were made using 855 mm focal length Ebert/Fastie-type spectrometer, with a 300 grooves/mm. grating and a solar tracker. Spectrometer provides a resolution of nearly 0.2 cm(-1) in the 2,000-3,500 cm(-1) spectral region. A thermoelectrically cooled PbSe detector and PC-based data acquisition system were used. The standard deviation of points for a day with steady conditions is typically 4-6%. Normally 10-30 spectra per day were observed, therefore a statistical 1-sigma uncertainty of the daily average was around 1%. Statistical uncertainty in the monthly mean amounted to 3-5%. The analysis of total column spectroscopic CO observations revealed positive linear trend between 1970 and 1999 of about 0.96 ppbv/yr or 0.9% per year. This rate of CO growth is almost 3 times higher than the rate between 1920 and 1950, obtained from ice core data (Haan et al., 1996). Sensitivities of CO mixing ratio in the troposphere to changes in total ozone and stratospheric aerosol have been assessed from the smoothed monthly measurements. Corrections due to unstable aerosol and total ozone were introduced into the experimental data. The CO trend over the entire measurement period which would be expected under conditions of constant 'undisturbed' total ozone and absence of stratospheric aerosol would be 1.3 ppbv/yr, or 30% higher than the observed trend. A positive trend in OH concentrations between 1980 and 1999 was estimated to be 0.6 +/- 0.3 %/yr. Analysis of total column CH, observations revealed positive linear trend between 1974 and 1999 of about 0,5 %/yr. Trend of H2O between 1986 and 1997 is equal to -1.1%/yr.