Data assimilation of satellite-retrieved ozone, carbon monoxide and nitrogen dioxide with ECMWF's Composition-IFS

Abstract

Daily global analyses and 5-day forecasts are generated in the context of the European Monitoring Atmospheric Composition and Climate (MACC) project using an extended version of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The IFS now includes modules for chemistry, deposition and emission of reactive gases, aerosols, and greenhouse gases, and the 4-dimensional variational data assimilation scheme makes use of multiple satellite observations of atmospheric composition in addition to meteorological observations. This paper describes the data assimilation setup of the new Composition-IFS (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O-3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation. The largest improvement in CO by assimilation of Measurements of Pollution in the Troposphere (MOPITT) CO columns is seen in the lower troposphere of the Northern Hemisphere (NH) extratropics during winter, and during the South African biomass-burning season. The assimilation of several O-3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O-3 analysis fields relative to the control run. The impact on lower tropospheric ozone, which comes from the residual of the total column and stratospheric profile O-3 data, is smaller, but nevertheless there is some improvement particularly in the NH during winter and spring. The impact of the assimilation of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) is small because of the short lifetime of NO2, suggesting that NO2 observations would be better used to adjust emissions instead of initial conditions. The results further indicate that the quality of the tropospheric analyses and of the stratospheric ozone analysis obtained with the C-IFS system has improved compared to the previous "coupled" model system of MACC

The ENSO signal in atmospheric composition fields: emission-driven versus dynamically induced changes

“…1) which leads to increased wet deposition and removal of aerosols, while not removing the gas-phase species in the same way. Inness et al, 2015).…”

“…A basic initial validation of C-IFS fields can be found in Flemming et al (2015) and Inness et al (2015) and more detailed validation of C-IFS can be found in the validation reports available from http://www.copernicus-atmosphere.eu/. The chemistry scheme implemented in the C-IFS model version used for these experiments is an extended, modified version of the Carbon Bond Mechanism 5 (Yarwood et al, 2005) chemical mechanism as originally implemented in the chemistry transport model TM5 (Tracer Model 5) (Huijnen et al, 2010;Williams et al, 2013;Huijnen et al, 2014).…”

Global high-resolution simulations of tropospheric nitrogen dioxide using CHASER V4.0

“…Global chemical data assimilation (e.g., Inness et al, 2015;Miyazaki et al, 2015) and emission inversion (e.g., Stavrakou et al, 2013;Miyazaki et al, 2017) would also benefit from high-resolution global CTMs through improvements in model performance (e.g., Arellano Jr. et al, 2007) and reduced spatial representation gaps between observed and simulated fields. Several previous studies (Mijling and van der A, 2012;Ding et al, 2017b;Liu et al, 2017) demonstrated the importance of high-resolution modeling in detecting small-scale NO x emission sources such as urban, new power plant, and ship emissions.…”

Geostationary Emission Explorer for Europe (G3E): mission concept and initial performance assessment

“…The background color code shows annual CO 2 emissions for the year 2013 as extracted from the database built by Oda and Maksyutov (2011). ing services such as developed within the European Copernicus programme (e.g. Inness et al, 2015).…”