The impact of Coriolis approximations on the environmental sensitivity of idealized extratropical cyclones
The precise influence of climate change on extratropical cyclone genesis and evolution is an important (but as yet unsolved) problem, given their physical and economic impact on a large portion of the planet’s population. However, extratropical cyclones are also affected by the competing influences of forcing mechanisms at a wide range of spatial scales, complicating the problem. While the advent of idealized numerical modeling has allowed great strides in addressing these complications and achieving some qualitative consensus in the literature, there is still some quantitative disagreement about response magnitude and where local maxima and minima in the response may be located. Thus, the advantages inherent in the variety of idealized numerical modeling methods used to address this problem are also a drawback, as it can be difficult to draw one-to-one comparisons across experiments. Although the effects of particular model architecture choices such as microphysical and cumulus schemes are well-documented, others are less understood. In this study, we examine the role of Coriolis approximations by comparing a new set of ETC sensitivity experiments using a linear β-plane approximation to an existing set of extratropical sensitivity experiments using a constant f-plane approximation. ETCs within the new β-plane experiment are found to generally decrease in strength with temperature, as measured by both minimum sea level pressure and maximum eddy kinetic energy (EKE). A small increase in EKE is observed at the warmest temperatures, likely due to diabatic influences disrupting flow within the warm conveyor belt. While seemingly contradictory to the previous f-plane results, the two experiments are instead found to be qualitatively similar upon further inspection, with an offset of approximately 8 K. This offset is primarily due to the Coriolis approximations, although the initial stability profile (affected by the Coriolis approximation) has a marginal influence.
KeywordsExtratropical cyclones Climate change Latent heat release Dynamical meteorology Idealized modeling Midlatitude meteorology
The authors thank the NASA Advanced Supercomputing Division for their help in using the Pleaides supercomputer as well as the University of Michigan’s Advanced Research Computing center for their help with the Flux high-performance computing cluster for their roles in our code refinement and completion of simulations. The authors would also like to acknowledge Shuguang Wang for his role in the development of this modeling framework. The research described in this manuscript was supported by NASA CloudSat/CALIPSO Science Team grant NNX13AQ33G, NASA PMM Science Team grant NNX16AD82G, and NSF grant AGS-1560844. A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Finally, the authors appreciate the time, comments, and suggestions of two anonymous reviewers, whose feedback helped to improve the first draft of this manuscript.
- Boutle IA (2009) Boundary-layer processes in mid-latitude cyclones. Doctoral dissertation, The University of ReadingGoogle Scholar
- Davis CA, Emanuel KA (1991) Potential vorticity diagnostics of cyclogenesis. Mon Weather Rev 119:1929–1953. https://doi.org/10.1175/1520-0493(1991)119%3c1929:PVDOC%3e2.0.CO;2 CrossRefGoogle Scholar
- Davis CA, Stoelinga MT, Kuo Y-H (1993) The integrated effect of condensation in numerical simulations of extratropical cyclogenesis. Mon Weather Rev 121:2309–2330. https://doi.org/10.1175/1520-0493(1993)121%3c2309:TIEOCI%3e2.0.CO;2 CrossRefGoogle Scholar
- Kain JS, Fritsch JM (1993) Convective parameterization for mesoscale models: the Kain-Fritsch Scheme. In: Emanuel KA, Raymond DJ (eds) The representation of cumulus convection in numerical models. Meteorological monographs, vol 24. American Meteorological Society, Boston, MA, pp 165–170Google Scholar
- Overland JE, Wang M (2010) Large-scale atmospheric circulation changes are associated with the recent loss of Arctic sea ice. Tellus 62A:1–9Google Scholar
- Parker DJ, Thorpe AJ (1995) Conditional convective heating in a baroclinic atmosphere: a model of convective frontogenesis. J Atmos Sci 52:1699–1711. https://doi.org/10.1175/1520-0469(1995)052%3c1699:CCHIAB%3e2.0.CO;2 CrossRefGoogle Scholar
- Posselt DJ, Martin JE (2004) The effect of latent heat release on the evolution of a warm occluded thermal structure. Mon Weather Rev 132:578–599. https://doi.org/10.1175/1520-0493(2004)132%3c0578:TEOLHR%3e2.0.CO;2 CrossRefGoogle Scholar
- Skamarock WC, Klemp JB, Dudhia J, Gill DO, Barker DM, Duda M, Huang X-Y, Wang W, Powers JG (2008) A description of the advanced research WRF Version 3, NCAR Technical Note http://www.mmm.ucar.edu/people/skamarock/
- Snyder C, Lindzen RS (1991) Quasi-geostrophic wave-CISK in an unbounded baroclinic shear. J Atmos Sci 48:78–88Google Scholar
- Stoelinga MT (1996) A potential vorticity-based study of the role of diabatic heating and friction in a numerically simulated baroclinic cyclone. Mon Weather Rev 124:849–874. https://doi.org/10.1175/1520-0493(1996)124%3c0849:APVBSO%3e2.0.CO;2 CrossRefGoogle Scholar
- Tierney G, 2017: An Examination of Extratropical Cyclone Sensitivity to Enviromental Variability. Doctoral dissertation, University of MichiganGoogle Scholar