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

Antje Inness ,A.-M Blechschmidt,M Crepulja,V Thouret,F Hendrick,Mihalis Vrekoussis ,John Kapsomenakis ,Mark Parrington ,Vincent‐Henri Peuch ,Martin Schultz ,Henk Eskes ,Simon Chabrillat ,Johannes Flemming ,Martin Suttie ,Idir Bouarar ,Richard Engelen ,Eleni Katragkou ,Andreas Richter ,Bavo Langerock ,Miha Razinger ,Audrey Gaudel ,Vincent Huijnen ,Luke Jones ,Arno Keppens ,Dimitrios Melas ,Annette Wagner ,Martine De Mazière ,C S Zerefos

doi:10.5194/acp-15-5275-2015

Abstract

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 (O3), 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 O3 total column and stratospheric profile retrievals greatly improves the total column, stratospheric and upper tropospheric O3 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 O3 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.

Highlights

Air pollution has become the biggest environmental health risk, killing about 7 million people in 2012, according to a recent World Health Organization study (WHO, 2014)
This paper describes the data assimilation setup of the new Composition-Integrated Forecasting System (IFS) (C-IFS) with respect to reactive gases and validates analysis fields of ozone (O3), carbon monoxide (CO), and nitrogen dioxide (NO2) for the year 2008 against independent observations and a control run without data assimilation
The impact of the assimilation of Measurements of Pollution in the Troposphere (MOPITT) total column CO (TCCO) data in CIFS-AN is evaluated by looking at the distribution of analysis departures (i.e. observation minus analysis values) in the form of histograms from CIFS-AN and CIFS-CTRL for 2008, for all MOPITT data that were flagged as good quality by the data producers (Fig. 2)

Summary

Introduction

Air pollution has become the biggest environmental health risk, killing about 7 million people in 2012, according to a recent World Health Organization study (WHO, 2014). It is important to provide air quality forecasts on global, regional and local scales to enable vulnerable people to take preventative action during pollution episodes. The Monitoring Atmospheric Composition and Climate (MACC) project (www.copernicus-atmosphere.eu) is the pre-operational atmospheric service of the European Copernicus programme funded by the European Commission’s Framework Program 7 (FP7). MACC will evolve into the Copernicus Atmospheric Monitoring Service in 2015. MACC combines state-of-the art chemistry and transport models with satellite data from various sensors to provide consistent global analyses and forecasts of 3-dimensional fields of the atmospheric composition, including ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), formaldehyde (HCHO), as well as methane (CH4), carbon dioxide (CO2) and aerosols (Flemming et al, 2013). For details of the system configuration, see http: //www.copernicus-atmosphere.eu/oper_info/. An earlier version of the system was used to produce a 10-year reanalysis of atmospheric composition data covering the years 2003 to 2012 (Inness et al, 2013)

Methods

Results

Conclusion