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Carbon monoxide

 

Carbon monoxide (CO) is one of the most important precursors of ozone (O3) and an important trace gas for the understanding of both air quality and climate forcing. Because of its relatively long lifetime (a few weeks to a few months depending on latitude and time of year), CO is one of the main tracers of long-range transport of pollution. Formed by the incomplete combustion of fossil and bio-fuels, and by vegetation burning, CO is also produced in the atmosphere via the oxidation of methane and non-methane hydrocarbons (NMHC) by the hydroxyl radical (OH). It is the largest global sink of the OH radical and thus plays an important role in the oxidizing power of the atmosphere and in the concentrations of greenhouse gases such as methane and O3. Hence, it contributes to climate change through its effect on ozone and methane chemistry. It is currently regulated by air quality standards worldwide as a major ozone precursor.


CO distributions are retrieved from IASI radiance spectra using a dedicated software, FORLI-CO, developed at Université Libre de Bruxelles (ULB) to handle as fast as possible all the IASI spectra, i.e. 1.3 millions of observations per day, disseminated through the Eumetsat data distribution system Eumetcast about 3 h after observation.  At LATMOS the IASI data are treated continuously on the calculation cluster of IPSL, in order to retrieve the CO global maps. The treatment of every spectrum is accomplished faster than 1/3 of second in order to assure the treatment of 15 Gb of data per day in real time. The CO total column maps are available here for the globe, Europe and North Pole in near real time. These data are also assimilated every day in the ECMWF model in the framework of the Copernicus/CAMS project in order to provide the forecast of the CO fields.


The IASI CO data are available from here http://www.pole-ether.fr/etherTypo/index.php?id=1701&L=0 (starting from 2008)


Figure 1. IASI nightime total column CO retrievals during the Greek fires event (here the image of 25 August 2007), interpolated on a 0.2o×0.2o grid [Turquety et al., 2009].

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