E01: Assessment of the Arctic lapse rate feedback using a multi-scale model hierarchy
The objective of E01 is to synthesise (AC)³ research with respect to Arctic feedback processes. The focus in phase II is on the lapse-rate feedback (LRF). E01 coordinates the (AC)³ crosscutting activity (CCA1) on this topic and feeds (AC)³ results from various investigations into models across scales, including the ICON general circulation model (GCM). In phase I, E01 investigated and quantified the physical feedback mechanisms in GCMs, with a focus on cloud feedback mechanisms that were investigated in detail making use of large-eddy simulations (LES). A key result of the multi-GCM analysis was that the LRF – the vertically non-uniform temperature change in the troposphere – stands out as one of the most important feedbacks (besides the surface albedo feedback) for Arctic amplification. Consequently, in the proposed phase II, we aim at a better understanding of the LRF in the Arctic, and its uncertainty.
A model hierarchy is adopted based on the ICON chain of models that covers a broad range of resolutions, from climate scale to eddy resolving. Global simulations, in combination with satellite observations, are used to better understand the dynamical and parametric sensitivities of surface temperature and free-tropospheric temperature changes. This will include an assessment of alterations of the radiative advective equilibrium that explains the free-tropospheric temperature in the Arctic winter. Composite output from large-scale simulations for present-day, evaluated with field campaign observations, and future scenarios are then used to drive representative process models at much higher resolutions. This will address a long-standing problem in Arctic climate modelling, which is a poor representation of the temperature inversion and associated small-scale processes including turbulence driven by cloud top cooling. The high-resolution simulations focus on air masses in four geographical regions of key importance for Arctic amplification, including the high Arctic, marginal sea ice zone, open ocean, and land masses. Field-campaign data in those regions will be used to constrain the simulations, including the upcoming MOSAiC, COMBLE and HALO-(AC)³ campaigns. Comparing resolved clouds and inversions under different climate forcing will provide new insights into the role of small-scale processes versus large-scale dynamics in the LRF. In addition, the research will further elucidate the impact of ocean-atmosphere interactions, in particular the role played by sea ice.
The lapse-rate feedback plays a key role in Arctic amplification, and the role of clouds, the surface energy budget, and meridional transports are key to better understand it.
Specifically, E01 will answer the questions:
- What drives the muted free-tropospheric warming? To which extent are components of the radiative – advective equilibrium altered in a warming climate?
- What does it take to realistically represent the temperature inversion and lack of vertical mixing in atmospheric models? Which role does cloud-top radiative cooling play?
- What governs the strong surface warming? How does it depend on changes of the underlying surface?
Achievements phase I
E01 has shown, that the total feedback in the Arctic in many global circulation models leads to a local runaway climate, due to the surface albedo and lapse rate feedback mechanisms (Block et al., 2020). The lapse rate feedback is strongest in boreal winter over sea ice and land, and is related to the temperature inversion strength (Lauer et al., 2019). Furthermore, the ICON modelling system has been thoroughly tested against observations in the Arctic (Neggers et al., 2019), and is ready for use in studies of feedback mechanisms in Arctic climate during phase II.
Role within (AC)³
Prof. Dr. Johannes Quaas
University of Leipzig
Leipzig Institute for Meteorology (LIM)
Prof. Dr. Roel Neggers
University of Cologne
Institute for Geophysics and Meteorology (IGM)
Block, K., F.A. Schneider, J. Mülmenstädt, M. Salzmann, and J. Quaas, 2020: Climate models disagree on the sign of total radiative feedback in the Arctic, Tellus A: Dynamic Meteorology and Oceanography, 72:1, 1-14,
Goren, T., J. Kazil, F. Hoffmann, T. Yamaguchi, and G. Feingold, 2019: Anthropogenic Air Pollution Delays Marine Stratocumulus Break‐up to Open‐Cells, Geophys. Res. Lett., https://doi.org/10.1029/2019GL085412
Wendisch, M., A. Macke, A. Ehrlich, C. Lüpkes, M. Mech, D. Chechin, K. Dethloff, C. Barrientos, H. Bozem, M. Brückner, H.-C. Clemen, S. Crewell, T. Donth, R. Dupuy, C. Dusny, K. Ebell, U. Egerer, R. Engelmann, C. Engler, O. Eppers, M. Gehrmann, X. Gong, M. Gottschalk, C. Gourbeyre, H. Griesche, J. Hartmann, M. Hartmann, B. Heinold, A. Herber, H. Herrmann, G. Heygster, P. Hoor, S. Jafariserajehlou, E. Jäkel, E. Järvinen, O. Jourdan, U. Kästner, S. Kecorius, E.M. Knudsen, F. Köllner, J. Kretzschmar, L. Lelli, D. Leroy, M. Maturilli, L. Mei, S. Mertes, G. Mioche, R. Neuber, M. Nicolaus, T. Nomokonova, J. Notholt, M. Palm, M. van Pinxteren, J. Quaas, P. Richter, E. Ruiz-Donoso, M. Schäfer, K. Schmieder, M. Schnaiter, J. Schneider, A. Schwarzenböck, P. Seifert, M.D. Shupe, H. Siebert, G. Spreen, J. Stapf, F. Stratmann, T. Vogl, A. Welti, H. Wex, A. Wiedensohler, M. Zanatta, S. Zeppenfeld, 2019: The Arctic Cloud Puzzle: Using ACLOUD/PASCAL Multi-Platform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification, Bull. Amer. Meteor. Soc., 100 (5), 841–871, doi:10.1175/BAMS-D-18-0072.1
Lauer, M., K. Block, M. Salzmann, and J. Quaas, 2019: CO2-forced changes of Arctic temperature lapse-rates in CMIP5 models, submitted to Met. Z.
Roode, S.R., T. Frederikse, A.P. Siebesma, A.S. Ackerman, J. Chylik, P.R. Field, J. Fricke, M. Gryschka, A. Hill, 2019: Turbulent transport in the gray zone: A large eddy model intercomparison study of the CONSTRAIN cold air outbreak case, Journal of Advances in Modeling Earth Systems, 11, 597– 623, doi:10.1029/2018MS001443
Pithan, F., G. Svensson, R. Caballero, D. Chechin, T.W. Cronin, A.M.L. Ekman, R. Neggers, M.D. Shupe, A. Solomon, M. Tjernström, and M. Wendisch, 2018: Role of air-mass transformations in exchange between the Arctic and mid-latitudes, Nature Geoscience, doi:10.1038/s41561-018-0234-1
Salzmann, M., 2017: The polar amplification asymmetry: Role of antarctic surface height, Earth Syst. Dynam., 8, 323-336, doi:10.5194/esd-8-323-2017