A03: Impact of low-level clouds and surface conditions on Arctic atmospheric boundary layer turbulence and radiation
To understand the role of atmospheric boundary layer (ABL) clouds in Arctic amplification, detailed studies of cloud–related processes influencing the ABL and the atmospheric energy budget are indispensable. The significance of these processes depends on various factors such as cloud macrophysical and microphysical properties, aerosol distributions, two–dimensional (2D) surface albedo, sea–ice characteristics,
and synoptic regime. To overcome our incomplete knowledge of the influence of these factors on Arctic amplification, in (AC)³ phase I, we have collected extensive data during a series of aircraft campaigns. The analyses revealed a clear impact of clouds on both radiation and turbulence in the ABL but also a large variability of flux profiles. Based on the airborne data we have quantified the cloud radiative forcing dependent on surface conditions. Furthermore, we investigated by theoretical and numerical studies different regimes of low and stability, e.g. those pointing to a large impact of leads on the surface energy budget.
Our studies during phase I focused on local processes. However, remote processes determining Arctic amplification, such as air-mass modifications and accompanying changes of cloud properties along their Lagrangian trajectories, have not yet been investigated. Moreover, seasonal changes of the cloud impact on the ABL energy budget have not been studied in phase I of this project. As a consequence, we propose two major goals for phase II of project A03. The first one aims at a better understanding of the seasonal dependence of the cloud impact on the ABL processes and energy budget. The second objective includes to investigate the changing cloud impact during Lagrangian airmass transports. To reach these goals, we will perform three campaigns using the AWI Polar 5/6 aircraft and the High Altitude and Long Range Research Aircraft (HALO). Two campaigns will be carried out accompanying the MOSAiC expedition using Polar 5 and 6 in spring and late summer 2020. These data will complement our earlier measurements within (AC)³ with respect to the seasonal cycle. The third campaign will be part of the HALO–(AC)³ mission in 2021, with the aim to investigate cloud transformations during meridional air–mass transports with a focus on warm air intrusions, but also looking at cold–air outbreaks.
To provide missing information on the small–scale 2D surface temperature distribution over fractional sea ice, we will extend the spectral radiation measurements into the thermal-infrared (TIR) by including a spectral TIR imager, which will be implemented on the Polar 5 aircraft and HALO. The new TIR imager will map 2D brightness temperature fields at six spectral bands with a horizontal resolution of less than 5 metres. These data will help to unravel the effects of horizontal inhomogeneities of surface emission on the surface radiative energy budget.
The net effect (warming/cooling) of Arctic low–level clouds is mostly driven by sea ice cover, but also varies on regional and seasonal scales.
Specific questions which will be answered in the project are:
- Are cloud and surface impacts on turbulent and radiative fluxes season-dependent?
- How do the ABL and clouds evolve along trajectories during air-mass transformations?
- How does small–scale inhomogeneity in the ABL depend on surface inhomogeneity?
- Do parametrizations of turbulence and radiation reproduce measurements?
Achievements phase I
A03 has quantified the cooling/warming effects of clouds as a function of surface properties using low-level aircraft measurements during ACLOUD and AFLUX (Stapf et al., 2019a). Measured radiation fields below clouds were compared with results of ICON simulations with 2.4 km resolution (Wendisch et al., 2019). It became apparent, that the measured surface albedo fields needed to be considered in the simulation to realistically represent the mode structure of the measured net radiation field by the ICON model. A large variability of the turbulent flux profiles inside the clouds depending on radiative cooling at cloud top was observed. A new parameterisation of the stability dependence of transfer coefficients for momentum, heat, and moisture was developed (Gryanik and Lüpkes, 2018). Furthermore, the warming effect of leads was quantified as a function of wind speed (Chechin et al., 2019). It was shown that leads might play a key role for the often observed development of decoupling between the sea ice surface temperature and the boundary layer temperature (Chechin and Lüpkes, 2019).
Role within (AC)³
Prof. Dr. Manfred Wendisch
University of Leipzig
Leipzig Institute for Meteorology (LIM)
Dr. Christof Lüpkes
Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research (AWI)
Am Handelshafen 12
Ehrlich, A., M. Wendisch, C. Lüpkes, M. Buschmann, H. Bozem, D. Chechin, H.-C. Clemen, R. Dupuy, O. Eppers, J. Hartmann, A. Herber, E. Jäkel, E. Järvinen, O. Jourdan, U. Kästner, L.-L. Kliesch, F. Köllner, M. Mech, S. Mertes, R. Neuber, E. Ruiz-Donoso, M. Schnaiter, J. Schneider, J. Stapf, and M. Zanatta, 2019: A comprehensive in situ and remote sensing data set from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, Earth Syst. Sci. Data, https://doi.org/10.5194/essd-11-1853-2019
Yu, X., A. Rinke, W. Dorn, G. Spreen, C. Lüpkes, H. Sumata, and V. Gryanik, 2019: Evaluation of Arctic sea-ice drift and its dependency on near-surface wind and sea-ice concentration and thickness in the coupled regional climate model HIRHAM-NAOSIM, The Cryosphere Discuss., doi:10.5194/tc-2019-183
Chechin D.G., I.A. Makhotina, C. Lüpkes, and A.P. Makshtas, 2019: Effect of wind speed and leads on clear-sky cooling over Arctic sea ice during polar night, J. Atmos. Sci., 76, 2481-2503, doi:10.1175/JAS-D-18-0277.1
Stapf, J., A. Ehrlich, E. Jäkel, C. Lüpkes, and M. Wendisch, 2019: Reassessment of the common concept to derive the surface cloud radiative forcing in the Arctic: Consideration of surface albedo – cloud interactions, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2019-534
Jonassen, M.O., D. Chechin, A. Yu. Karpechko, C. Lüpkes, T. Spengler, A. Tepstra, T. Vihma, and X. Zhang, 2019: Dynamical Processes in the Arctic Atmosphere. In: A. A. Kokhanovsky, and C. Tomasi (Eds.): Physics and chemistry of Arctic atmosphere, Springer, accepted
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
Chechin, D.G. and C. Lüpkes, 2019: Baroclinic low-level jets in Arctic marine cold-air outbreaks, IOP Conf. Series: Earth and Environmental Science, 231, 012011, IOP Publishing, doi:10.1088/1755-1315/231/1/012011
Knudsen, E.M., B. Heinold, S. Dahlke, H. Bozem, S. Crewell, I. V. Gorodetskaya, G. Heygster, D. Kunkel, M. Maturilli, M. Mech, C. Viceto, A. Rinke, H. Schmithüsen, A. Ehrlich, A. Macke, C. Lüpkes, M. Wendisch, 2018: Meteorological conditions during the ACLOUD/PASCAL field campaign near Svalbard in early summer 2017, Atmos. Chem. Phys., 18, 17995-18022, doi:10.5194/acp-18-17995-2018
Lüpkes, C., A. Schmitt and V. Gryanik, 2018: Turbulente Energie- und Impulsflüsse in der atmosphärischen Grenzschicht über dem polaren Ozean, promet, 102, 61-74
Järvinen, E., O. Jourdan, D. Neubauer, B. Yao, C. Liu, M.O. Andreae, U. Lohmann, M. Wendisch, G.M. McFarquhar, T. Leisner, and M. Schnaiter, 2018: Additional global climate cooling by clouds due to ice crystal complexity, Atmos. Chem. Phys., 18, 15767-15781, doi:10.5194/acp-18-15767-2018
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
Gryanik, V.M. and Lüpkes, C., 2018: An efficient non-iterative bulk parametrization of surface fluxes for stable atmospheric conditions over polar sea ice, Bound.-Lay. Meteorol., 166, 301-325, doi:10.1007/s10546-017-0302-x
Wendisch, M., M. Brückner, J. P. Burrows, S. Crewell, K. Dethloff, K. Ebell, Ch. Lüpkes, A. Macke, J. Notholt, J. Quaas, A. Rinke, and I. Tegen, 2017: Understanding causes and effects of rapid warming in the Arctic. Eos, 98, doi:10.1029/2017EO064803
Chechin, D. G. and Lüpkes, C., 2017: Boundary-layer development and low-level baroclonicity during high-latitude clod-air outbreaks: A simple model, Boundary-Layer Meteorol., 162, 91-116, doi:10.1007/s10546-016-0193-2
Bühl, J., Alexander, S., Crewell, S., Heymesfield, A., Kalesse, H., Khain, A., Maahn, M., van Tricht, K., Wendisch, M., 2017: Ice Formation and Evolution in Clouds and Precipitation: Measurement and Modeling Challenges, Baumgardner, D., McFarquhar, G., and Heymsfield, A. (Eds.), Chapter 10: Remote Sensing, AMS Meteorological Monographs, 58, 10.1-10.21, doi:10.1175/AMSMONOGRAPHS-D-16-0015.1