Source-receptor relationships for airborne measurements of CO<sub>2</sub>, CO and O<sub>3</sub> above Siberia: a cluster-based approach

Abstract

Abstract. We analysed results of three intensive aircraft campaigns above Siberia (April and September 2006, August 2007) with a total of ∼70 h of continuous CO 2 , CO and O 3 measurements. The flight route consists of consecutive ascents and descents between Novosibirsk (55 • N, 82 • E) and Yakutsk (62 • N, 129 • E). We performed retroplume calculations with the Lagrangian particle dispersion model FLEX-PART for many short segments along the flight tracks. To reduce the extremely rich information on source regions provided by the model calculation into a small number of distinct cases, we performed a statistical clustering -to our knowledge for the first time -into potential source regions of the footprint emission sensitivities obtained from the model calculations. This technique not only worked well to separate source region influences but also resulted in clearly distinct tracer concentrations for the various clusters obtained. High CO and O 3 concentrations were found associated with agricultural fire plumes originating from Kazakhstan in September 2006. A statistical analysis indicates that summer uptake of CO 2 is largely explained (∼50% of variance) by air mass exposure to uptake by Siberian and sub-arctic ecosystems. This resulted in an average 5 to 10 ppm difference with overlaying air masses. Stratosphere-troposphere exchange is found to strongly influence the observed O 3 mixing ratios in spring, but not in summer. to lower mixing ratios in spring, when the airmass aerosol burden is important. In the lower troposphere, large-scale deposition processes in the boreal and sub-arctic boundary layer is a large O 3 sink, resulting in a ∼20 ppb difference with overlaying air masses. Lagrangian footprint clustering is very promising and could also be advantageously applied to the interpretation of ground based measurements including calculation of tracers' sources and sinks.

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

“…Boreal forest fires are also an important source of PAN and, due to their proximity to the Arctic, plumes can be transported to high latitudes during the spring and summer months (Brock et al, 2011;Singh et al, 2010). Whilst little O 3 production appears to occur close to boreal fires (Alvarado et al, 2010;Paris et al, 2010), several recent studies have shown O 3 production downwind from boreal fires in the Arctic during the summer months (Wespes et al, 2012;Parrington et al, 2012;Thomas et al, 2013). Nevertheless, O 3 production is higher in air masses influenced by anthropogenic emissions.…”

Pan-Eurasian Experiment (PEEX): towards a holistic understanding of the feedbacks and interactions in the land–atmosphere–ocean–society continuum in the northern Eurasian region

“…Arctic tropospheric ozone is significantly influenced by long-range import of ozone and precursors from midlatitude sources as well as by boreal wildfires Wespes et al, 2012;Paris et al, 2010b;Vivchar et al, 2009). The role of biomass burning emissions in the ozone budget in high latitudes remains controversial.…”

Simulation of variability in atmospheric carbon dioxide using a global coupled Eulerian – Lagrangian transport model

“…More recently, LPDMs have been used for various research applications at a regional scale (Lin et al, 2003(Lin et al, , 2006(Lin et al, , 2007Paris et al, 2010;Warneke et al, 2009). When applying an LPDM for global analysis, a long-term integration is required (see Stohl et al, 2010), although this approach is not as computationally efficient as that of Eulerian models.…”