Sensitivity of bias adjustment methods to low-frequency internal climate variability over the reference period: an ideal model study. (28th June 2022)

• Record Type: Journal Article
• Authors: Bonnet, Rémy; Boucher, Olivier; Vrac, Mathieu; Jin, Xia
• Is Part Of: Environmental research. Volume 1:Number 1(2022)
• Publication Date: 2022-06-28
• Subjects: bias adjustment -- Internal climate variability -- climate change -- climate projection -- impact studies; Climatic changes -- Periodicals; Climatic changes -- Research -- Periodicals; Climate change mitigation -- Periodicals; Global environmental change -- Periodicals; 363.7387405
• DOI: 10.1088/2752-5295/ac6adc
• Languages: English
• ISSNs: 2752-5295

Abstract

Abstract: Climate simulations often need to be adjusted before carrying out impact studies at a regional scale. Technically, bias adjustment methods are generally calibrated over the last few decades, in order to benefit from a more comprehensive and accurate observational network. At these timescales, however, the climate state may be influenced by the low-frequency internal climate variability. There is therefore a risk of introducing a bias to the climate projections by bias-adjusting simulations with low-frequency variability in a different phase to that of the observations. In this study, we developed a new pseudo-reality framework using an ensemble of simulations from the IPSL-CM6A-LR climate model in order to assess the impact of the low-frequency internal climate variability of the North Atlantic sea surface temperatures on bias-adjusted projections of mean and extreme surface temperature over Europe. We show that using simulations in a similar phase of the Atlantic Multidecadal Variability reduces the pseudo-biases in temperature projections. Therefore, for models and regions where low frequency internal variability matters, it is recommended to sample relevant climate simulations to be bias adjusted in a model ensemble or alternatively to use a very long reference period when possible.