Preprints
https://doi.org/10.5194/acp-2021-63
https://doi.org/10.5194/acp-2021-63

  18 Feb 2021

18 Feb 2021

Review status: this preprint is currently under review for the journal ACP.

Contrasting characteristics of open- and closed- cellular stratocumulus cloud in the Eastern North Atlantic

Michael P. Jensen1, Virendra P. Ghate2, Dié Wang1, Diana K. Apoznanski3, Mary J. Bartholomew1, Scott E. Giangrande1, Karen L. Johnson1, and Mandana M. Thieman4,5 Michael P. Jensen et al.
  • 1Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USA
  • 2Climate and Earth System Department, Argonne National Laboratory, Argonne, IL, USA
  • 3Department of Meteorology and Atmospheric Sciences, Pennsylvania State University, University Park, PA, USA
  • 4Science Systems and Applications, Inc., Hampton, VA, USA
  • 5NASA Langley Research Center, Hampton, VA, USA

Abstract. Extensive regions of marine boundary layer cloud impact the radiative balance through their significant shortwave albedo while having little impact on outgoing longwave radiation. Despite this importance, these cloud systems remain poorly represented in large-scale models due to difficulty in representing the processes that drive their lifecycle and coverage. In particular, the mesoscale organization, and cellular structure of marine boundary clouds has important implications for the subsequent cloud feedbacks. In this study, we use long-term (2013–2018) observations from the Atmospheric Radiation Measurement (ARM) Facility's Eastern North Atlantic (ENA) site on Graciosa Island, Azores, Portugal to identify cloud cases with open- or closed-cellular organization. More than 500 hours of each organization type are identified. The ARM observations are combined with reanalysis and satellite products to quantify the cloud, precipitation, aerosol, thermodynamic and large-scale synoptic characteristics associated with these cloud types. Our analysis shows that both cloud organization populations occur during similar sea surface temperature conditions, but the open-cell cases are distinguished by stronger cold-air advection and large-scale subsidence compared to the closed-cell cases, consistent with their formation during cold-air outbreaks. We also find that the open-cell cases were associated with deeper boundary layers, stronger low-level winds, and higher-rain rates compared to their closed-cell counterparts. Finally, raindrops with diameters larger than one millimeter were routinely recorded at the surface during both populations, with a higher number of large drops during the open-cellular cases. The similarities and differences noted herein provide important insights into the environmental and cloud characteristics during varying marine boundary layer cloud mesoscale organization and will be useful for the evaluation of model simulations for ENA marine clouds.

Michael P. Jensen et al.

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2021-63', Anonymous Referee #1, 22 Apr 2021 reply

Michael P. Jensen et al.

Michael P. Jensen et al.

Viewed

Total article views: 294 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
213 76 5 294 2 2
  • HTML: 213
  • PDF: 76
  • XML: 5
  • Total: 294
  • BibTeX: 2
  • EndNote: 2
Views and downloads (calculated since 18 Feb 2021)
Cumulative views and downloads (calculated since 18 Feb 2021)

Viewed (geographical distribution)

Total article views: 366 (including HTML, PDF, and XML) Thereof 366 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 05 May 2021
Download
Short summary
This work compares the large-scale meteorology, cloud, aerosol, precipitation and thermodynamics of closed- and open-cell cloud organizations using long-term observations from the Eastern North Atlantic. Open-cell cases are associated with cold-air outbreaks and occur in deeper boundary layers, with stronger winds and higher rain rates compared to closed-cell cases. These results offer important benchmarks for model representation of boundary layer clouds in this climatically important region.
Altmetrics