Preprints
https://doi.org/10.5194/egusphere-2023-2416
https://doi.org/10.5194/egusphere-2023-2416
01 Nov 2023
 | 01 Nov 2023

Aerosol-Induced Closure of Marine Cloud Cells: Enhanced Effects in the Presence of Precipitation

Matthew W. Christensen, Peng Wu, Adam C. Varble, Heng Xiao, and Jerome D. Fast

Abstract. The Weather Research Forecasting (WRF) V4.2 model is configured within a Lagrangian framework to quantify the impact of aerosols on evolving cloud fields. Simulations employing realistic meteorological boundary conditions are based on 10 case study days offering diverse meteorology during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA). Cloud and aerosol retrievals in observations from aircraft measurements, ground-based Atmosphere Radiation Measurement (ARM) data at Graciosa Island in the Azores, and A-Train and geostationary satellites are in good agreement with the simulations. Higher aerosol concentration leads to suppressed drizzle and increased cloud water content. These changes lead to larger radiative cooling rates at cloud top, enhanced vertical velocity variance, and increased vertical and horizontal wind speed near the base of the lower-tropospheric inversion. As a result, marine cloud cell area expands, narrowing the gap between shallow clouds and increasing cloud optical thickness, liquid water content, and the top-of-atmosphere outgoing shortwave flux. While similar aerosol effects are observed in lightly to non-raining clouds, they tend to be smaller by comparison. These results show a strong link between cloud cell area expansion and the radiative adjustments caused by liquid water path and cloud fraction changes. These adjustments scale by 74 % and 51 %, respectively, relative to the Twomey effect. Given the limitations of traditional global climate model resolutions, addressing mesoscale cloud-state transitions at kilometer-scale resolutions or higher should be of utmost importance in accurately quantifying aerosol radiative forcing.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Matthew W. Christensen, Peng Wu, Adam C. Varble, Heng Xiao, and Jerome D. Fast

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2416', Anonymous Referee #1, 22 Nov 2023
  • RC2: 'Comment on egusphere-2023-2416', Michael Diamond, 05 Dec 2023
  • AC1: 'Comment on egusphere-2023-2416', Matthew Christensen, 03 Feb 2024

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2416', Anonymous Referee #1, 22 Nov 2023
  • RC2: 'Comment on egusphere-2023-2416', Michael Diamond, 05 Dec 2023
  • AC1: 'Comment on egusphere-2023-2416', Matthew Christensen, 03 Feb 2024
Matthew W. Christensen, Peng Wu, Adam C. Varble, Heng Xiao, and Jerome D. Fast
Matthew W. Christensen, Peng Wu, Adam C. Varble, Heng Xiao, and Jerome D. Fast

Viewed

Total article views: 574 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
401 144 29 574 32 18 23
  • HTML: 401
  • PDF: 144
  • XML: 29
  • Total: 574
  • Supplement: 32
  • BibTeX: 18
  • EndNote: 23
Views and downloads (calculated since 01 Nov 2023)
Cumulative views and downloads (calculated since 01 Nov 2023)

Viewed (geographical distribution)

Total article views: 559 (including HTML, PDF, and XML) Thereof 559 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 21 May 2024
Download
Short summary
Clouds are essential to keep Earth cooler by reflecting sunlight back to space. We show that an increase in aerosol concentration suppresses precipitation in clouds, causing them to accumulate water and expand in a polluted environment with stronger turbulence and radiative cooling. This process enhances their reflectance by 51 %. It’s therefore prudent to account for cloud fraction changes in assessments of aerosol-cloud interactions to improve predictions of climate change.