EGU21-7035
https://doi.org/10.5194/egusphere-egu21-7035
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Purposeful weighting of components in geochemical (compositional) data

Karel Hron1, Alessandra Menafoglio2, Javier Palarea-Albaladejo3, Peter Filzmoser4, and Juan Jose Egozcue5
Karel Hron et al.
  • 1Palacky University, Department of Mathematical Analysis and Applications of Mathematics, Olomouc, Czechia (hronk@seznam.cz)
  • 2MOX - Department of Mathematics, Politecnico di Milano, Milan, Italy (alessandra.menafoglio@polimi.it)
  • 3Biomathematics and Statistics Scotland, Edinburgh, United Kingdom (javier.palarea@bioss.ac.uk)
  • 4Institute of Statistics and Mathematical Methods in Economics, Vienna University of Technology, Vienna, Austria (peter.filzmoser@tuwien.ac.at)
  • 5Department of Applied Mathematics III, Universitat Politecnica de Catalunya, Barcelona, Spain (juan.jose.egozcue@upc.edu)

For varied reasons, in practical analysis of geochemical (compositional) data we are often interested in adjusting the role or the influence of variables on the final results. For instance, a measuring device used to analyse the chemical mixture of soil samples might not necessarily have the same accuracy for all components, particularly for those with low concentrations. This can have a severe impact on results and interpretation of popular methods like principal component analysis, regression analysis or clustering, but also on the quality of imputation of values below detection limit of a measurement device. In all these cases, a sensible weighting scheme for the variables would generally lead to a statistical analysis better reflecting the underlying phenomenon of interest and less influenced by some limitations or issues with the data collection process. In addition, the relative nature of geochemical data (i.e., those in units like mg/kg, proportions or percentages), where the relevant information is contained in ratios between components, needs to be taken into account for a reliable statistical processing. In this contribution we propose a sensible way of weighting of geochemical components using a generalisation of the logratio methodology for compositional data analysis, namely, the Bayes space approach. We provide practical examples of such weighting and also highlight that the Bayes space approach enables one to develop a methodological framework where it is possibly to apply any weighting strategy in a controlled way.

How to cite: Hron, K., Menafoglio, A., Palarea-Albaladejo, J., Filzmoser, P., and Egozcue, J. J.: Purposeful weighting of components in geochemical (compositional) data, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7035, https://doi.org/10.5194/egusphere-egu21-7035, 2021.

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