EGU24-16824, updated on 11 Mar 2024
https://doi.org/10.5194/egusphere-egu24-16824
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Global changes in low-level circulation types under future anthropogenic forcing

Juan Antonio Fernandez de la Granja1, Ana Casanueva2,3, Joaquín Bedia2,3, Swen Brands1, and Jesús Fernández1
Juan Antonio Fernandez de la Granja et al.
  • 1Instituto de Física de Cantabria (IFCA), CSIC - Universidad de Cantabria, 39005 Santander, Spain (juan.fernandez@unican.es)
  • 2Dept. Matemática Aplicada y Ciencias de la Computación (MACC), Universidad de Cantabria, 39005 Santander, Spain
  • 3Grupo de Meteorología y Computación, Universidad de Cantabria, Unidad Asociada al CSIC, Santander, 39005, Spain.

Large-scale atmospheric circulation determines regional near-surface climate and, ultimately, causes diverse impacts on ecosystems and societies. Possible modifications of such large-scale features due to global warming would inevitably lead to changes in the weather regimes, affecting the local-to-regional climate response. Weather Type (WT) classification methods, such as the one proposed by Jenkinson and Collison (1977), provide a way to summarize mid-latitude, low-level circulation at a regional-scale (Jones et al, 2013; Fernández-Granja et al, 2023). JC-WTs classify sea-level pressure into 27 WTs spanning different local air flow directions and shear vorticities. This methodology can be used to evaluate Global Climate Models (GCMs), which stand as a key tool in the study of past and future climate evolution. Despite obvious biases, historical GCM simulations show a reasonable representation of the frequency of WTs worldwide (Brands 2022; Brands et al, 2023) and the newest model generation shows consistent improvements in the representation of WT occurrence (Fernández-Granja et al, 2021). This leads to the question of how WTs will evolve along the century under anthropogenic forcing. In this work, we address this question by considering an ensemble of GCMs from the CMIP5 and CMIP6 initiatives under different emission scenarios. We focused on evaluating the variations of the JC-WT frequencies under climate change, considering how they emerge from natural variability. Also, we analyzed the consistency between CMIP5 and CMIP6 WT projections and their associated uncertainties. The JC-WT classification was applied globally, so our findings can inform any climate impact research where changes in large-scale circulation play a fundamental role.

Acknowledgement: This work is part of project CORDyS (PID2020-116595RB-I00) funded by MCIN/AEI/10.13039/501100011033. J.A.F. acknowledges support from project ATLAS (PID2019-111481RB-I00) and grant PRE2020-094728 funded by MCIN/AEI/10.13039/501100011033 and ESF investing in your future.

References:

Brands, S., 2022. A circulation-based performance atlas of the CMIP5 and 6 models for regional climate studies in the Northern Hemisphere mid-to-high latitudes. Geoscientific Model Development 15, 1375–1411. DOI: 10.5194/gmd-15-1375-2022

Brands S, Fernández-Granja JA, Bedia J, et al (2023) A global climate model performance atlas for the southern hemisphere extratropics based on regional atmospheric circulation patterns. Geophysical Research Letters 50(10). DOI: 10.1029/2023GL103531

Fernández-Granja JA, Casanueva A, Bedia J, et al (2021b) Improved atmospheric circulation over Europe by the new generation of CMIP6 earth system models. Climate Dynamics 56:3527–3450. DOI: 10.1007/s00382-021-05652-9

Fernández-Granja, J. A., Brands, S., Bedia, J., et al (2023) Exploring the limits of the Jenkinson–Collison weather types classification scheme: a global assessment based on various reanalyses. Climate Dynamics. DOI: 10.1007/s00382-022-06658-7

Jones P.D., Harpham C., Briffa K.R. (2013) Lamb weather types derived from reanalysis products. International Journal of Climatology 33(5):1129–1139. DOI: 10.1002/joc.3498

Jenkinson A., Collison F. (1977) An initial climatology of gales over the north sea. synoptic climatology branch memorandum. Meteorological Office, 62

Keywords: Jenkinson–Collison classification, weather types, global climate models, climate change.

How to cite: Fernandez de la Granja, J. A., Casanueva, A., Bedia, J., Brands, S., and Fernández, J.: Global changes in low-level circulation types under future anthropogenic forcing, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16824, https://doi.org/10.5194/egusphere-egu24-16824, 2024.

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