Global Sensitivity Analysis of environmental models: Convergence and validation

Fanny J Sarrazin, Francesca Pianosi, Thorsten Wagener

Research output: Contribution to journalArticle (Academic Journal)peer-review

135 Citations (Scopus)
527 Downloads (Pure)

Abstract

We address two critical choices in Global Sensitivity Analysis (GSA): the choice of the sample size and of the threshold for the identification of insensitive input factors. Guidance to assist users with those two choices is still insufficient. We aim at filling this gap. Firstly, we define criteria to quantify the convergence of sensitivity indices, of ranking and of screening, based on a bootstrap approach. Secondly, we investigate the screening threshold with a quantitative validation procedure for screening results. We apply the proposed methodologies to three hydrological models with varying complexity utilizing three widely-used GSA methods (RSA, Morris, Sobol’). We demonstrate that convergence of screening and ranking can be reached before sensitivity estimates stabilize. Convergence dynamics appear to be case-dependent, which suggests that “fit-for-all” rules for sample sizes should not be used. Other modellers can easily adopt our criteria and procedures for a wide range of GSA methods and cases.
Original languageEnglish
Pages (from-to)135-152
Number of pages18
JournalEnvironmental Modelling and Software
Volume79
Early online date13 Feb 2016
DOIs
Publication statusPublished - May 2016

Keywords

  • Sensitivity Analysis
  • Screening
  • Ranking
  • Convergence
  • Validation
  • SWAT

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