Modelling the impacts of future enhanced winter warming events on subarctic ecosystems using LPJ-GUESS

Abstract

Winter warming events (WWEs) are short-lasting events of unusually warm weather, occasionally combined with rainfall, which can cause severe ecosystem impacts by altering ground temperatures and water fluxes. These impacts are generally overlooked in large-scale ecosystem models. The frequency and intensity of WWEs will likely increase further in the future. We used an ecosystem model, LPJ-GUESS, to investigate the responses of four subarctic ecosystems to different levels of predicted WWEs, and identify model gaps hindering accurate estimates of these responses. In response to WWEs, the model simulated substantial ground cooling (up to 2 °C in winter) in contrast to the observed warming, leading to changes in biogeochemical fluxes often comparable in magnitude to those from altered winter climatologies. The mismatch between the modelled and the observed ground temperature changes may be due to the 1) lacking surface energy balance, 2) daily timestep, and 3) simplistic water retention scheme in LPJ-GUESS.

Accounting for Winter Warming Events in the Ecosystem Model LPJ‐GUESS: Evaluation and Outlook

“…The output data in the supporting information, figures, and/or tables, can be retrieved from the following in‐text data citation reference: Pascual et al. (2024) (data set accessible at https://zenodo.org/records/10639128).…”

“…et al (2023) (data set accessible at https://doi.org/10.5281/zenodo.10397218),Pascual and Johansson (2023) (data set available at https://zenodo.org/records/10397360), Johansson, M. (2024) (data set available at https:// zenodo.org/records/10656709),Heliasz (2012) (data set accessible at https://doi.org/10.5281/zenodo.10675679), andChristensen et al (2012) (data accessible at https://doi.org/10.1007/s13280-012-0302-5).The output data in the supporting information, figures, and/or tables, can be retrieved from the following in-text data citation reference:Pascual et al (2024) (data set accessible at https://zenodo.org/records/10639128).…”