Output data from the MIMICA LES model to study the transition from aerosol-limited to updraft-limited susceptibility regime

Matthias Schwarz, Julien Savre, Dipu Sudhakar, Johannes Quaas, Annica M. L. Ekman

Selected raw model output from large-eddy simulations (LES) conducted with MISU MIT Cloud and Aerosol (MIMICA) model to study the transition from aerosol- to updraft-limited susceptibility regime.

The meteorological setup of the simulations represents an idealized case of a drizzling nocturnal stratocumulus-topped marine boundary layer and is based upon observations collected during the second research flight (RF02) of the Second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field study. Susceptibility simulations (with varying aerosol concentrations) were conducted for different model setups to investigate if the model can capture the transition from the aerosol- to the updraft-limited susceptibility regime.

The data was used to investigate if an LES code with explicit aerosol-cloud interactions and a widely used two-moment bulk microphysical scheme can reproduce the susceptibility regimes — i.e. the updraft-limited regime (typically occurring at high aerosol number concentrations and low updraft speeds) and the aerosol-limited regime (typically occurring at low aerosol number concentrations and high updraft speeds) — identified by detailed parcel model simulations and observations.

Citation

Matthias Schwarz, Julien Savre, Dipu Sudhakar, Johannes Quaas, Annica M. L. Ekman (2023) Output data from the MIMICA LES model to study the transition from aerosol-limited to updraft-limited susceptibility regime. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/schwarz-2023-mimica-les-1

References

Schwarz M, Savre J, Sudhakar D, Quaas J, Ekman AML (2024) The Transition from Aerosol- to Updraft-Limited Susceptibility Regime in Large-Eddy Simulations with Bulk Microphysics. Tellus B: Chemical and Physical Meteorology 76:32⁠ – ⁠46. https://doi.org/10.16993/tellusb.94

Savre J, Ekman AML, Svensson G (2014) Technical note: Introduction to MIMICA, a large-eddy simulation solver for cloudy planetary boundary layers. J Adv Model Earth Syst 6:630⁠ – ⁠649. https://doi.org/10.1002/2013MS000292

Reutter P, Su H, Trentmann J, Simmel M, Rose D, Gunthe SS, Wernli H, Andreae MO, Pöschl U (2009) Aerosol- and updraft-limited regimes of cloud droplet formation: influence of particle number, size and hygroscopicity on the activation of cloud condensation nuclei (CCN). Atmos Chem Phys 9:7067⁠ – ⁠7080. https://doi.org/10.5194/acp-9-7067-2009

Stevens B, Lenschow DH, Vali G, et al. (2003) Dynamics and Chemistry of Marine Stratocumulus—DYCOMS-II. Bull Amer Meteor Soc 84:579⁠⁠ – ⁠594. https://doi.org/10.1175/BAMS-84-5-579

Data description

The data are provided in a large (7.6 GiB) zip file. The directories of the directory tree is used to indicate the model setup. The file tree containing all sets of sensitifity simulations looks like the list below.

Directory structure

• FDT simulations with fixed timestep
  • dt_1e-1_r0_1e-6 dt = 0.1 s, r0 = 1 micrometer
  • dt_1e-1_r0_rwet dt = 0.1s, r0 from wet aerosol PSD
  • dt_1e-1_r0_rwet_noREN dt = 0.1s, r0 from wet aerosol PSD, no renormalization
• LRD large domain simulations
  • r0_01e-06
  • r0_05e-06
  • r0_10e-06
• SMD small domain simulations
  • r0_010e-7
  • r0_020e-7
  • r0_030e-7
  • r0_040e-7
  • r0_050e-7
  • r0_060e-7
  • r0_070e-7
  • r0_080e-7
  • r0_090e-7
  • r0_100e-7
  • rwet

In each of the above direcories, a set of simulations are stored where the directory name indicated the prescribed aerosol number concentration (in #/kg) e.g.,:

• 10e07
• 10e08
• 10e09
• 10e10
• 50e07
• 65e06

The output data contains (a) 3D output (for the last simulated hour 18000 s to 21600 s), (b) profiles, and (c) time series for relevant atmospheric variables (e.g., cloud droplet number density, aerosol number density, updraft velocity, relative humidity, etc.).

• DYCOMS_MPI.nc 3D output (for the last simulated hour 18000 s to 21600 s; NetCDF file)
• T_S time series (text file)
• profiles_tot.nc profiles (NetCDF file)

The output data contains

• 3D output (for the last simulated hour 18000 s to 21600 s; NetCDF File with filename DYCOMS_MPI.nc),
• profiles (NetCDF File with filename profiles_tot.nc), and
• time series (Text file with filename T_S),

for relevant atmospheric variables (e.g., cloud droplet number density, aerosol number density, updraft velocity, relative humidity, etc.).

Comments

With this dataset and the code from the GITHUB repository matschwa/2023-LES-susceptibility all plots and analysis from the paper by Schwarz et al. (2023) can be reproduced.

The MIMICA model is described by Savre et al. (2014).

The DYCOMS-II field study is described by Stevens et al. (2003).

The transition from the aerosol- to the updraft-limited susceptibility regime was first described by Reutter et al. (2009).