Rebuilding sources of linear tracers after atmospheric concentration measurements

Issartel, Jean-Pierre

doi:10.5194/acp-3-2111-2003

Cited by 33 publications

(34 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As noticed in (Issartel, 2003) this strategy is not well defined. Compared to the atmosphere the samples are very small so that the r i display peaks by the position of the detectors.…”

Section: Reminder About the Illuminationmentioning

confidence: 96%

“…We proposed in (Issartel, 2003) to smooth the inversion by introducing a renormalising function f (x)≥0 and a new product ( , ) f :…”

Section: Reminder About the Illuminationmentioning

confidence: 99%

“…2). The latter was introduced in (Issartel, 2003) to give the singularities a sense. The, influence of the detectors could then be efficiently controlled by means of weights empirically adjusted to the various parts, in space and time, of the domain under investigation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Emergence of a tracer source from air concentration measurements, a new strategy for linear assimilation

Issartel

2005

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. The measurement of atmospheric concentrations by a monitoring network is a promising tool for the identification of the widespread sources of trace species. The paper addresses the case of the species scattered linearly by a known meteorology. The question is classical: what can be said about the source from a set of measurements? Is it possible to guess from the values observed by the measurements that the source is spread close to the detectors, or that the tracer comes from a remote region? And, if the source was a point source, would it be possible to understand it by just considering these values? A part of the answers is a matter of practical sense: the resolution with which an emission can be retrieved will always be limited and probably lower for a remote region, even if the detectors and dispersion model are error free. The paper proposes a linear strategy of inference: to any set of values taken by the observed concentrations is associated linearly an estimate of the source. Doubled values lead to a doubled estimate. The method, based on adjoint techniques, is intended to optimise the resolution by quantifying, with the concept of illumination, which regions are well, poorly or not seen at all. The illumination tied to ordinary adjoint functions becomes excessive close to the detectors thus leading to inversion artefacts. This may be corrected by attributing each point of the space time domain a geometric and statistical weight. The adjoint functions are transformed. The choice of this renormalising function is constrained by an unambiguous entropic criterion preventing any overestimation of the available information that would lead to artefacts. It amounts to evenly distribute the information between the points organised with their weights as a "known domain". The theory is illustrated by calculations performed with the experimental source ETEX1.

show abstract

“…As noticed in (Issartel, 2003) this strategy is not well defined. Compared to the atmosphere the samples are very small so that the r i display peaks by the position of the detectors.…”

Section: Reminder About the Illuminationmentioning

confidence: 96%

“…We proposed in (Issartel, 2003) to smooth the inversion by introducing a renormalising function f (x)≥0 and a new product ( , ) f :…”

Section: Reminder About the Illuminationmentioning

confidence: 99%

See 1 more Smart Citation

Emergence of a tracer source from air concentration measurements, a new strategy for linear assimilation

Issartel

2005

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…By adjoint modelling, Issartel (2003) applied the concept of retroplumes for source identification and estimates within the framework of "illumination". A similar approach was studied by and .…”

Section: Introductionmentioning

confidence: 99%

Emission rate and chemical state estimation by 4-dimensional variational inversion

et al. 2007

View full text Add to dashboard Cite

Abstract. This study aims to assess the potential and limits of an advanced inversion method to estimate pollutant precursor sources mainly from observations. Ozone, sulphur dioxide, and partly nitrogen oxides observations are taken to infer source strength estimates. As methodology, the fourdimensional variational data assimilation technique has been generalised and employed to include emission rate optimisation, in addition to chemical state estimates as usual objective of data assimilation. To this end, the optimisation space of the variational assimilation system has been complemented by emission rate correction factors of 19 emitted species at each emitting grid point, involving the University of Cologne mesoscale EURAD model. For validation, predictive skills were assessed for an August 1997 ozone episode, comparing forecast performances of pure initial value optimisation, pure emission rate optimisation, and joint emission rate/initial value optimisation.Validation procedures rest on both measurements withheld from data assimilation and prediction skill evaluation of forecasts after the inversion procedures. Results show that excellent improvements can be claimed for sulphur dioxide forecasts, after emission rate optimisation. Significant improvements can be claimed for ozone forecasts after initial value and joint emission rate/initial value optimisation of precursor constituents. The additional benefits applying joint emission rate/initial value optimisation are moderate, and very useful in typical cases, where upwind emission rate optimisation is essential. In consequence of the coarse horizontal model grid resolution of 54 km, applied in this study, comparisons indicate that the inversion improvements can rest on assimilating ozone observations only, as the inclusion of NO x observations does not provide additional forecast skill. Emission estimates were found to be largely independent from initial Correspondence to: H. Elbern (he@eurad.uni-koeln.de) guesses from emission inventories, demonstrating the potential of the 4D-var method to infer emission rate improvements. The study also points to the need for improved horizontal model resolution to more efficient use of NO x observations.

show abstract

“…Then, instead of the adjoint model itself, one needs solutions to it, called retroplumes. These methods have been adapted to atmospheric problems (Uliasz, 1983;Uliasz and Pielke, 1991;Marchuk, 1995;Pudykiewicz, 1998;Issartel and Baverel, 2003;Issartel, 2003). Variational assimilation on ETEX-I data has been used by Langner (1997, 1998).…”

Section: Introductionmentioning

confidence: 99%

Source reconstruction of an accidental radionuclide release at European scale

Krysta¹,

Bocquet²

2007

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

ABSTRACT:We develop and experiment with new techniques to reconstruct the source of an accidental release of radionuclides at continental scale. The prior information on the source to be accounted for in the inversion is identified. Using methods based on information theory, purposeful cost functions consistent with this prior are constructed. They generalize classical variational least-square assimilation techniques. The adjoint of the numerical dispersion model POLAIR3D is used in the minimization of these cost functions. The method is tested on a set of twin experiments involving the main European civil nuclear sites as candidate sources. Several experiments are performed. They demonstrate how sensitive the retrievals are to the prior, the meteorological conditions, the source profile shape and the errors. A reconstruction is then attempted on the Algeciras incident, which took place in southern Spain in May 1998. A truly successful three-dimensional inversion is out of reach with the available observations. However, a temporal reconstruction of the event succeeds, and this exemplifies the newly designed cost functions.

show abstract

Rebuilding sources of linear tracers after atmospheric concentration measurements

Cited by 33 publications

References 27 publications

Emergence of a tracer source from air concentration measurements, a new strategy for linear assimilation

Emergence of a tracer source from air concentration measurements, a new strategy for linear assimilation

Emission rate and chemical state estimation by 4-dimensional variational inversion

Source reconstruction of an accidental radionuclide release at European scale

Contact Info

Product

Resources

About