Quantifying uncertainties due to chemistry modelling – evaluation of tropospheric composition simulations in the CAMS model (cycle 43R1)
<p>We report on an evaluation of tropospheric ozone and its precursor gases in three atmospheric chemistry versions as implemented in the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS), referred to as IFS(CB05BASCOE), IFS(MOZART) and IFS(MOCAGE)....
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-04-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/12/1725/2019/gmd-12-1725-2019.pdf |
| Summary: | <p>We report on an evaluation of tropospheric ozone and its
precursor gases in three atmospheric chemistry versions as implemented in the
European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated
Forecasting System (IFS), referred to as IFS(CB05BASCOE), IFS(MOZART) and
IFS(MOCAGE). While the model versions were forced with the same overall
meteorology, emissions, transport and deposition schemes, they vary largely
in their parameterisations describing atmospheric chemistry, including the
organics degradation, heterogeneous chemistry and photolysis, as well as
chemical solver. The model results from the three chemistry versions are
compared against a range of aircraft field campaigns, surface observations,
ozone-sondes and satellite observations, which provides quantification of the
overall model uncertainty driven by the chemistry parameterisations. We find
that they produce similar patterns and magnitudes for carbon monoxide (CO)
and ozone (<span class="inline-formula">O<sub>3</sub></span>), as well as a range of non-methane hydrocarbons
(NMHCs), with averaged differences for <span class="inline-formula">O<sub>3</sub></span> (CO) within 10 %
(20 %) throughout the troposphere. Most of the divergence in the
magnitude of CO and NMHCs can be explained by differences in OH
concentrations, which can reach up to 50 %, particularly at high
latitudes. There are also comparatively large discrepancies between model
versions for <span class="inline-formula">NO<sub>2</sub></span>, <span class="inline-formula">SO<sub>2</sub></span> and <span class="inline-formula">HNO<sub>3</sub></span>, which are
strongly influenced by secondary chemical production and loss. Other common
biases in CO and NMHCs are mainly attributed to uncertainties in their
emissions. This configuration of having various chemistry versions within IFS
provides a quantification of uncertainties induced by chemistry modelling in
the main CAMS global trace gas products beyond those that are constrained by
data assimilation.</p> |
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| ISSN: | 1991-959X 1991-9603 |