Distribution-based pooling for combination and multi-model bias correction of climate simulations - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Preprints, Working Papers, ... Year : 2023

Distribution-based pooling for combination and multi-model bias correction of climate simulations

Abstract

For the study of climate change, many General Circulation Models (GCM)s have been designed, modeling the climate on the planet Earth slightly differently either by emphasizing predictions in specific regions or by incorporating varied or uniquely modeled parameters. To extract a robust signal from the diverse outputs, models are typically combined into multimodel ensembles. Their results are summarized in various ways, including (possibly weighted) multimodel means, medians and other statistics, within a Bayesian framework or not. In this work, we introduce an new probability aggregation method termed "alpha-pooling" which builds an aggregated Cumulative Probability Function (CPF) designed to be closer to a reference CPF over the calibration period. α-pooling assigns a weight to each CPF, which is an increasing function of its closeness to the reference CPF. Key to the α-pooling is a parameter α that describes the type of aggregation, which includes linear aggregation and log-linear aggregation. We first establish that α-pooling is a proper aggregation method verifying some optimal properties. Then, focusing on climate models over Western Europe, several experiments are run in order to assess the performance of αpooling against methods currently available, including multi-model means and weighted variants. A perfect model experiment and a sensitivity analysis to the set of climate models are run. Our findings demonstrate the superiority of the proposed method, indicating that alpha-pooling presents a robust and efficient way to combine GCM's CPF. The results of this study show that the CDFs pooling strategy for "multi-model bias correction" is a credible alternative to usual GCM-by-GCM correction methods, by allowing to handle and consider several climate models at once.
Fichier principal
Vignette du fichier
AlphaPooling_HAL_2023_10_08.pdf (2.01 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

hal-04232474 , version 1 (08-10-2023)

Identifiers

  • HAL Id : hal-04232474 , version 1

Cite

Mathieu Vrac, Denis Allard, Gregoire Mariethoz, Soulivanh Thao, Lucas Schmutz. Distribution-based pooling for combination and multi-model bias correction of climate simulations. 2023. ⟨hal-04232474⟩
26 View
16 Download

Share

Gmail Facebook X LinkedIn More