Changes of Intense Extratropical Cyclone Deepening Mechanisms in a Warmer Climate in Idealized Simulations
- Author(s)
- Ting Chen Chen, Christoph Braun, Aiko Voigt, Joaquim G. Pinto
- Abstract
To understand how extratropical cyclones (ETCs) may change in a warmer climate, we conduct idealized baroclinic life cycle simulations using the Icosahedral Nonhydrostatic (ICON)–NWP model with varied initial conditions. With respect to a present-day climate, two experiments are highlighted: a 4-K uniform warming and a more realistic late twenty-first-century warming pattern projected by a Coupled Model Intercomparison Project, version 6 (CMIP6), model. Different ETC deepening mechanisms, especially by diabatic processes, are quantified via the pressure tendency equation analysis, and the horizontal model resolution dependency is examined by contrasting coarse-grid (80 km) and convection-permitting (2.5 km) simulations. While our simulated ETCs are primarily baroclinically driven, dominated by the horizontal warm-air advection in the air column above the surface low, such an effect only strengthens by 10% in both warming experiments. However, the direct contribution of diabatic heating to surface pressure drop almost doubles, which likely feeds back positively to horizontal warm-air advection. Although their combined response to warming is pronounced, it is largely offset by the strengthened adiabatic cooling (17%) due to enhanced upward motions in warmer and moister ETCs, leading to a marginal ETC deepening at maturity (lowers by;1.5–4 hPa). Nevertheless, the near-surface impacts strongly increase, particularly the local extreme precipitation (up to 56%). The convection-permitting and the coarse-grid simulations show qualitatively consistent ETC responses to global warming. We suggest that the systematically weaker ETCs (with higher central pressure) in 2.5-km compared to 80-km simulations might be primarily caused by model uncertainty in representing the convective-diabatic heating over the warm front near the cyclone core.
- Organisation(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- Karlsruher Institut für Technologie
- Journal
- Journal of Climate
- Volume
- 37
- Pages
- 4703-4722
- No. of pages
- 20
- ISSN
- 0894-8755
- DOI
- https://doi.org/10.1175/JCLI-D-23-0605.1
- Publication date
- 09-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105205 Climate change
- Keywords
- ASJC Scopus subject areas
- Atmospheric Science
- Sustainable Development Goals
- SDG 13 - Climate Action
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/f79b1de9-1f30-406e-ab49-e2ab390f2841