Spectroscopic Measurements of CO and NO2 Total Column Amounts: Trajectory Analysis Using ECMWF Data Set.

Carbon monoxide (CO) resides mostly in the troposphere. Total column amounts of carbon monoxide were measured at two sites in Hokkaido Isl. (Japan) and at the Zvenigorod Research Station near Moscow using infrared spectroscopy and the Sun as a source of direct radiation. Nitrogen dioxide (NO₂) has a stratospheric component (between 1 and 6 E15 mol/ cm2 ), and a tropospheric contribution, that varies from almost zero up to 6 E15 mol/cm 2 for the most polluted days. Spectra of the solar scattered radiation in the absorption band of NO₂ during sunrise and sunset were measured at the Zvenigorod station using a grating UV/Vis zenith-looking spectrometer. NO₂ slant path amount is derived as a function of solar zenith angle. The shape of this function depends on vertical distribution of NO₂ and allows one to estimate tropospheric contribution into the vertical NO₂ column amount. Back isentropic trajectories were constructed for these two observational sites for 1, 3, 5, and 7 km arrival heights above sea level. EDGAR gridded inventory and hot spots detected by ATSR were used for assessment of contributions from various surface sources. A long-range transport of CO from European and Asian sources was confirmed.