The YAK-AEROSIB transcontinental aircraft campaigns: new insights on the transport of CO 2 , CO and O 3 across Siberia

J.-D. Paris (1, 2) , Philippe Ciais (1, 3) , P. Nedelec (4) , M. Ramonet (1, 2) , B. Belan (5) , M. Yu. Arshinov (5) , G. Golitsyn (6) , I. Granberg (6) , A. Stohl (7) , G. Cayez (4) , G. Athier (4) , F. Boumard (1) , J.-M. Cousin (4)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 ICOS-RAMCES - ICOS-RAMCES
3 ICOS-ATC - ICOS-ATC
4 LAERO - Laboratoire d'aérologie
5 IAO - V.E. Zuev Institute of Atmospheric Optics
6 IAP - A.M.Obukhov Institute of Atmospheric Physics
7 NILU - Norwegian Institute for Air Research

Two airborne campaigns were carried out to measure the tropospheric concentrations and variability of CO 2 , CO and O 3 over Siberia. In order to quantify the influence of remote and regional natural and anthropogenic sources, we analysed a total of 52 vertical profiles of these species collected in April and September 2006, every ∼200 km and up to 7 km altitude. CO 2 and CO concentrations were high in April 2006 (respectively 385-390 ppm CO 2 and 160-200 ppb CO) compared to background values. CO concentrations up to 220 ppb were recorded above 3.5 km over eastern Siberia, with enhancements in 500-1000 m thick layers. The presence of CO enriched air masses resulted from a quick frontal uplift of a polluted air mass exposed to northern China anthropogenic emissions and to fire emissions in northern Mongolia. A dominant Asian origin for CO above 4 km (71.0%) contrasted with a dominant European origin below this altitude (70.9%) was deduced both from a transport model analysis, and from the contrasted CO/ CO 2 ratio vertical distribution. In September 2006, a significant O 3 depletion (∼-30 ppb) was repeatedly observed in the boundary layer, as diagnosed from virtual potential temperature profiles and CO 2 gradients, compared to the free troposphere aloft, suggestive of a strong O 3 deposition over Siberian forests.

Domaines: Océan, Atmosphère

J.-D. Paris, Philippe Ciais, P. Nedelec, M. Ramonet, B. Belan, et al.. The YAK-AEROSIB transcontinental aircraft campaigns: new insights on the transport of CO 2 , CO and O 3 across Siberia. Tellus B - Chemical and Physical Meteorology, 2008, 60 (4), pp.551-568. ⟨10.1111/j.1600-0889.2008.00369.x⟩. ⟨hal-02926830⟩