The impact of biomass burning on upper tropospheric carbon monoxide: a study using MOCAGE global model and IAGOS airborne data

Abstract

Abstract. In this paper, the fate of biomass burning emissions of carbon monoxide is studied with the global chemistry–transport model MOCAGE (MOdélisation de Chimie Atmosphérique à Grande Échelle) and IAGOS (In-Service Aircraft for a Global Observing System) airborne measurements for the year 2013. The objectives are firstly to improve their representation within the model and secondly to analyse their contribution to carbon monoxide concentrations in the upper troposphere. At first, a new implementation of biomass burning injection is developed for MOCAGE, using the latest products available in Global Fire Assimilation System (GFAS) biomass burning inventory on plume altitude and injection height. This method is validated against IAGOS observations of CO made in fire plumes, identified thanks to the SOFT-IO source attribution data. The use of these GFAS products leads to improved MOCAGE skill to simulate fire plumes originating from boreal forest wildfires. It is also shown that this new biomass burning injection method modifies the distribution of carbon monoxide in the free and upper troposphere, mostly at northern boreal latitudes. Then, MOCAGE performance is evaluated in general in the upper troposphere and lower stratosphere in comparison to the IAGOS observations and is shown to be very good, with very low bias and good correlations between the model and the observations. Finally, we analyse the contribution of biomass burning to upper tropospheric carbon monoxide concentrations. This is done by comparing simulations where biomass are toggled on and off in different source regions of the world to assess their individual influence. The two regions contributing the most to upper tropospheric CO are found to be the boreal forests and equatorial Africa, in accordance with the quantities of CO they emit each year and the fact that they undergo fast vertical transport: deep convection in the tropics and pyroconvection at high latitudes. It is also found that biomass burning contributes more than 11 % on average to the CO concentrations in the upper troposphere and up to 50 % at high latitudes during the wildfire season.

The 2017 Mega-Fires in Central Chile: Impacts on Regional Atmospheric Composition and Meteorology Assessed from Satellite Data and Chemistry-Transport Modeling

“…Chemistry-transport modeling (CTM) offers a solution to cope with such limitations, hence the extensive use of CTM scenario approaches to describe and assess the transport and impact of biomass burning emissions on atmospheric composition at the global, e.g., [19][20][21] and regional scale, e.g., [22][23][24]. In particular, the CHIMERE model [25] is extensively used for the study of atmospheric impacts of large biomass burning events in several areas of the world, with examples of application in Africa [26], Russia [27][28][29], and the Mediterranean [30][31][32].…”

Origins and characterization of CO and O<sub>3</sub> in the African upper troposphere

“…Briefly, SOFT-IO is a scientific tool which couples FLEXPART 20-day backward plumes of air masses for all the aircraft tracks with global anthropogenic and fire emission inventories for CO, and has been used in various studies (e.g. Cussac et al, 2020;Petetin et al, 2018) to investigate and quantify anthropogenic and biomass burning origin in CO measurements. For the entire IAGOS flight track, SOFT-IO v1.0 estimates the CO contribution (in ppb) of recent (≤ 20 days before) worldwide emissions.…”

Pollution trace gas distributions and their transport in the Asian monsoon upper troposphere and lowermost stratosphere during the StratoClim campaign 2017

“…Thereby, the emissions were increased globally in all NMVOC emission sources by 50 %. In both simulations, the meteorological fields were specified by the European Centre for Medium-Range Weather Forecasts (ECMWF) European Reanalysis Interim (ERA-Interim; Dee et al, 2011), and all simulations were initialized on 1 May 2017.…”

“…In the contemporary understanding, the chemical composition of the confined system of the AMA is dominated by enhanced amounts of tropospheric trace gases, such as water vapor (H 2 O) and carbon monoxide (CO), which are transported to higher altitudes (Santee et al, 2017). Several model studies have identified the impact of different source regions and long-range transport on the AMA, either with artificial tracers (e.g., Vogel et al, 2015Vogel et al, , 2016Vogel et al, , 2019 or, e.g., CO as a proxy (Pan et al, 2016;Cussac et al, 2020). However, large discrepancies are observed in ASM radiative heating rates between different reanalyses (Randel and Jensen, 2013), which result in uncertainties in diabatic vertical transport.…”