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Carbon monoxide (CO)

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.

The IASI CO Level 2 products are retrieved in a near real time mode using the Fast Optimal Retrievals on Layers for IASI CO (FORLI-CO) software (Hurtmans et al., 2012), which was developed by ULB in collaboration with LATMOS. These data are assimilated every day in the European Centre for Medium-Range  Weather  Forecasts  (ECMWF) model in the framework of the Copernicus Atmosphere Monitoring Service (CAMS) project in order to provide the forecast of the CO fields. These data were also used in the framework of the QA4ECV (Quality Assurance for multi-decadal ECVs) European Union Framework 7 project aiming at developing a robust system for the quality assurance of satellite and in-situ algorithm that will be applied to essential climate variables (ECVs). The IASI CO products retrieved using FORLI-CO is the official IASI/Eumetsat CO product since 2 March 2017.

The IASI daily CO products are distributed via the AERIS data center and are available at

Figure 1. 11-year global distribution of CO total columns (in molecules/cm2) retrieved
from IASI/Metop-A observations (2008-2018) (Courtesy Maya George).

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