On the tuning of atmospheric inverse methods: comparisons with the European Tracer Experiment (ETEX) and Chernobyl datasets using the atmospheric transport model FLEXPART

Author(s)
Ondřej Tichý, Lukáš Ulrych, Nikolaos Evangeliou, Andreas Stohl
Abstract

Estimation of the temporal profile of an atmospheric release, also called the source term, is an important problem in environmental sciences. The problem can be formalized as a linear inverse problem wherein the unknown source term is optimized to minimize the difference between the measurements and the corresponding model predictions. The problem is typically ill-posed due to low sensor coverage of a release and due to uncertainties, e.g., in measurements or atmospheric transport modeling; hence, all state-of-the-art methods are based on some form of regularization of the problem using additional information. We consider two kinds of additional information: the prior source term, also known as the first guess, and regularization parameters for the shape of the source term. While the first guess is based on information independent of the measurements, such as the physics of the potential release or previous estimations, the regularization parameters are often selected by the designers of the optimization procedure. In this paper, we provide a sensitivity study of two inverse methodologies on the choice of the prior source term and regularization parameters of the methods. The sensitivity is studied in two cases: data from the European Tracer Experiment (ETEX) using FLEXPART v8.1 and the caesium-134 and caesium-137 dataset from the Chernobyl accident using FLEXPART v10.3.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
Institute of Information Theory and Automation (UTIA), Norwegian Institute for Air Research
Journal
Geoscientific Model Development
Volume
13
Pages
5917–5934
No. of pages
18
ISSN
1991-959X
DOI
https://doi.org/10.5194/gmd-13-5917-2020
Publication date
12-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
105204 Climatology, 105206 Meteorology
Keywords
ASJC Scopus subject areas
Earth and Planetary Sciences(all), Modelling and Simulation
Portal url
https://ucris.univie.ac.at/portal/en/publications/on-the-tuning-of-atmospheric-inverse-methods-comparisons-with-the-european-tracer-experiment-etex-and-chernobyl-datasets-using-the-atmospheric-transport-model-flexpart(14d4091c-e626-4de0-b3ca-ac620ea1cbd9).html