Coupling global chemistry transport models to ECMWF's integrated forecast system

Abstract

Abstract. The implementation and application of a newly developed coupled system combining ECMWF's integrated forecast system (IFS) with global chemical transport models (CTMs) is presented. The main objective of the coupled system is to enable the IFS to simulate key chemical species without the necessity to invert the complex source and sink processes such as chemical reactions, emission and deposition. Thus satellite observations of atmospheric composition can be assimilated into the IFS using its 4D-VAR algorithm. In the coupled system, the IFS simulates only the transport of chemical species. The coupled CTM provides to the IFS the concentration tendencies due to emission injection, deposition and chemical conversion. The CTMs maintain their own transport schemes and are fed with meteorological data at hourly resolution from the IFS. The CTM used in the coupled system can be either MOZART-3, TM5 or MOCAGE. The coupling is achieved via the special-purpose software OA-SIS4. The scientific integrity of the coupled system is proven by analysing the difference between stand-alone CTM simulations and the tracer fields in the coupled IFS. The IFS concentration fields match the CTM fields for about 48 h with the biggest differences occurring in the planetary boundary layer (PBL). The coupled system is a good test bed for processoriented comparison of the coupled CTM. As an example, the vertical structure of chemical conversion and emission injection is studied for a ten day period over Central Europe for the three CTMs.

Online coupled regional meteorology chemistry models in Europe: current status and prospects

“…Flemming et al, 2009), prescribed fields describing clean or polluted background atmospheres (e.g. climatological averages, see also Tang et al, 2007), or either of those methods modified with increments from a chemical data assimilation system (Elbern and Schmidt, 2001).…”

“…ECMWF uses the 4DVar data assimilation developed for data assimilation in NWP to assimilate observations of atmospheric composition. In its current configuration, ECMWF's IFS (Table 4) has been extended to simulate transport, source and sink processes of atmospheric chemical species as follows (Hollingsworth et al, 2008): aerosol processes are simulated in an online coupled manner in IFS (Morcrette et al, 2009), whereas source and sink processes of reactive gaseous species are treated via a two-way coupled global chemical transport model (Flemming et al, 2009). This coupled system has been run with MOZART-3 and TM5.…”

“…The ECMWF (European Centre for Medium-Range Weather Forecast) meteorological forecast and data assimilation system IFS (Integrated Forecast System, http://www.ecmwf.int/ research/ifsdocs) has been coupled to an updated version of the global chemistry transport model MOZART-3 (Model for Ozone And Related Tracers, version 3; Kinnison et al, 2007) in order to build the coupled MACC system IFS-MOZART (Flemming et al, 2009). For coupled simulations, both models are run in parallel and exchange meteorological fields as well as 3-D source and sink terms every hour using the OASIS4 coupling software developed in the PRISM project (Valcke and Redler, 2006).…”

Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide

“…Furthermore, satellite observations of atmospheric composition are a very important part of operational chemical weather forecasting as it is for example carried out by the Copernicus Atmosphere Monitoring Service (http: //atmosphere.copernicus.eu/), which uses data assimilation techniques (Lahoz and Schneider, 2014) to make the best use of the satellite information of atmospheric composition (Flemming et al, 2009;Inness et al, 2013). The Copernicus Atmosphere Monitoring Service is being developed within the framework of a series of EU-funded research projects, the latest of them being the Monitoring Atmospheric Composition and Climate -Interim Implementation (MACC-II).…”

Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

“…Within the Monitoring Atmospheric Composition and Climate (MACC) and the Global and regional Earth-system Monitoring using Satellite and in situ data (GEMS) project (Hollingsworth et al, 2008), the Integrated Forecasting System (IFS) of ECWMF, which had been used to produce the ERA40 and ERA-Intrim meteorological re-analysis, was extended to simulate chemically reactive gases (Flemming et al, 2009), aerosols (Morcrette et al, 2009Benedetti et al, 2008) and greenhouse gases (Engelen et al, 2009), so that ECMWF's 4D-Var system (Courtier et al, 1994;Rabier et al, 2000) could be used to assimilate satellite observations of atmospheric composition together with meteorological observations on the global scale.…”