The workshop on parameter estimation and inverse modelling for atmospheric composition was held at ECMWF from 22 to 24 October 2013.
Under the umbrella of the EU-funded projects GEMS, MACC, and MACC-II, ECMWF has extended its data assimilation and forecasting system to include atmospheric composition. Analyses and forecasts of reactive gases, greenhouse gases, and aerosol are now routinely provided on a daily basis. At the same time the EU-funded GEOLAND and GEOLAND2 projects have extended the ECMWF land surface model to include a simple representation of the carbon cycle. As part of the European GMES framework it is envisaged that this atmospheric composition data assimilation and forecasting system will become fully operational to provide daily global forecasts on top of ECMWF's meteorological forecasts.
The modelling and data assimilation of atmospheric composition differs in several ways from the modelling and data assimilation for numerical weather prediction, such as the atmospheric chemistry, available observations, and the greater importance of mass conservation for long-lived tracers. However, another important aspect is the significance of the boundary conditions. Anthropogenic emissions, greenhouse gas surface fluxes, wild fire emissions, and volcanic eruptions form a significant part of the assimilation and forecasting problem, which can therefore not really be treated as an initial condition problem with a (almost) perfect model. Current practice is to prescribe these boundary conditions based on emission inventories, off-line carbon flux models, off-line fire detection systems, and ad-hoc definition of volcanic emissions. However, for a future operational forecasting system better solutions should be found in order to minimize the model error. This is especially important with the introduction of long-window 4D-Var.
The aim of the workshop is to explore the options to optimally define the boundary conditions in a near-real-time 4D-var data assimilation system. Some progress has already been made, e.g., the use of the CTESSEL land surface model to provide land surface fluxes for atmospheric CO2 or the use of the GFAS fire detection system to provide fire emissions in near-real-time, but many other improvements should be explored. There is significant experience in the research community with flux inversions, estimating volcanic emissions, and optimizing emission estimates. An important question for the workshop is therefore how to combine existing forward models with inverse modelling techniques, e.g., through parameter estimation, in an operational environment.
|Constraining surface models|
The use of the CTESSEL land carbon model in the MACC-II CO2 modelling system
Anna Agusti-Panareda (ECMWF)
Process parameter optimisation in terrestrial carbon cycle models: the curse of the forecast
Marko Scholze (Lund University)
From global to regional inverse modelling for greenhouse gases
Frederic Chevallier (LSCE)
The interaction of scales between carbon cycling in the atmosphere and in the terrestrial biosphere
Wouter Peters (University of Wageningen)
|Constraining surface models/ Optimizing surface emissions|
Estimation of surface fluxes of carbon and heat from atmospheric data assimilation
Eugenia Kalnay (University of Maryland)
Estimating emission rates of reacting constituents by variational inversion
Hendrik Elbern (University of Köln)
Estimating surface NOx and CO emissions and lightning NOx sources by assimilating satellite observations of multiple chemical species
Kazuyuki Miyazaki (JAMSTEC)
Experiences with data assimilation and parameter estimation for air quality at TNO
Martijn Schaap/Arjo Segers (TNO)
|Optimizing surface emissions/ Contraining point sources|
Use of 4D-VAR assimilation for emission source apportionment
Mikhail Sofiev (FMI)
Volcanic plume modelling and assimilation in the MACC-II system
Johannes Flemming (ECMWF)
Source term determination for volcanic eruptions (and other point-source releases)
Andreas Stohl (NILU)
Theoretical aspects of emission inverse modelling and parameter estimation with chemical transport models
Marc Bocquet (CEREA)
High resolution modelling of fires within the Euro-Mediterranean region
Jean-Baptiste Filippi (University of Corsica)