05 Nov 2021
05 Nov 2021
Status: a revised version of this preprint is currently under review for the journal ACP.

Aerosol-cloud-turbulence interactions in well-coupled Arctic boundary layers over open water

Jan Chylik1, Dmitry Chechin2, Regis Dupuy3, Birte S. Kulla1, Christof Lüpkes4, Stephan Mertes5, Mario Mech1, and Roel A. J. Neggers1 Jan Chylik et al.
  • 1Institute for Geophysics and Meteorology, University of Cologne, Germany
  • 2Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russia
  • 3Université Clermont Auvergne, CNRS, Laboratoire de Météorologie Physique (LaMP), F-63000 Clermont-Ferrand, France
  • 4Alfred Wegener Institute (AWI), Bremerhafen, Germany
  • 5Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany

Abstract. Late springtime Arctic mixed-phase convective clouds over open water in the Fram Strait as observed during the recent ACLOUD field campaign are simulated at turbulence-resolving resolutions. The main research objective is to gain more insight into the coupling of these cloud layers to the surface, and into the role played by interactions between aerosol, hydrometeors and turbulence in this process. A composite case is constructed based on data collected by two research aircraft on 18 June 2017. The boundary conditions and large-scale forcings are based on weather model analyses, yielding a simulation that freely equilibrates towards the observed thermodynamic state. The results are evaluated against a variety of independent aircraft measurements. The observed cloud macro- and microphysical structure is well reproduced, consisting of a stratiform cloud layer in mixed-phase fed by surface-driven convective transport in predominantly liquid phase. Comparison to noseboom turbulence measurements suggests that the simulated cloud-surface coupling is realistic. A joint-pdf analysis of relevant state variables is conducted, suggesting that locations where the mixed-phase cloud layer is strongly coupled to the surface by convective updrafts act as hot-spots for invigorated interactions between turbulence, clouds and aerosol. A mixing-line analysis reveals that the turbulent mixing is similar to warm convective cloud regimes, but is accompanied by hydrometeor transitions that are unique for mixed-phase cloud systems. Distinct fingerprints in the joint-pdf diagrams also explain i) the typical ring-like shape of ice mass in the outflow cloud deck, ii) its slightly elevated buoyancy, and iii) an associated local minimum in CCN.

Jan Chylik et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2021-888', Anonymous Referee #1, 21 Nov 2021
  • RC2: 'Comment on acp-2021-888', Ian Brooks, 11 Feb 2022
    • AC2: 'Reply on RC2', Jan Chylik, 21 Apr 2022

Jan Chylik et al.

Data sets

Case simulation: LES RF20 composite case Chylik, Jan; Chechin, Dmitry; Dupuy, Regis; Kulla, Birte S.; Lüpkes, Christof; Mertes, Stephan; Mech, Mario; Neggers, Roel A. J.

Model code and software

Dales4.3_sb3 Chiel van Heerwaarden, sjboeing, Huug Ouwersloot, thijsheus, Jisk Attema, Fredrik Jansson, Sylwester Arabas, Jordi Vila, sderoode, afmoene, Bart van Stratum, Jan Chylik

Jan Chylik et al.


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Short summary
Arctic low-level clouds play an important role in the ongoing warming of the Arctic. Unfortunately, these clouds are not properly represented in weather forecast and climate models. This study tries to cover this gap by focusing on clouds over open water during the spring, observed by research aircrafts near Svalbard. The study combines the high-resolution model with sets of observational data. The results show the importance of processes that involve both ice and the liquid water in the clouds.