Preprints
https://doi.org/10.5194/egusphere-2024-1033
https://doi.org/10.5194/egusphere-2024-1033
11 Apr 2024
 | 11 Apr 2024
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Diurnal evolution of non-precipitating marine stratocumuli in an LES ensemble

Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold

Abstract. We explore the impacts of the diurnal cycle, free-tropospheric (FT) humidity values, and interactive surface fluxes on the cloud system evolution of non-precipitating marine stratocumuli based on a large ensemble of large-eddy simulations. Cases are separated into three categories based on their degree of decoupling and cloud liquid water path (LWPc). A new budget analysis method is proposed to analyze the evolution of LWPc under both coupled and decoupled conditions. More coupled clouds start with relatively low LWPc and cloud fraction (fc) but experience the least decrease in LWPc and fc during the daytime. More decoupled clouds undergo greater daytime reduction in LWPc and fc, especially those with higher LWPc at sunrise because they suffer from faster weakening of a net radiative cooling. During the nighttime, a positive correlation between FT humidity and LWPc emerges, consistent with higher FT humidity reducing both radiative cooling and the humidity jump, both of which reduce entrainment and increase LWPc. The time rate of change in the LWPc is more likely to be negative for higher LWPc and greater inversion base height (zi), conditions under which entrainment dominates as turbulence develops. In the morning, the rate of the LWPc reduction depends on the LWPc at sunrise, zi, and the degree of decoupling, with distinct contributions from subsidence and radiation. Under well-mixed conditions, it takes about 10 h for the surface fluxes to offset 15 % of the changes in entrainment warming and drying, assuming no changes in transfer coefficients or surface wind speed.

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.
Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold
Yao-Sheng Chen, Jianhao Zhang, Fabian Hoffmann, Takanobu Yamaguchi, Franziska Glassmeier, Xiaoli Zhou, and Graham Feingold

Viewed

Total article views: 206 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
150 45 11 206 13 9 8
  • HTML: 150
  • PDF: 45
  • XML: 11
  • Total: 206
  • Supplement: 13
  • BibTeX: 9
  • EndNote: 8
Views and downloads (calculated since 11 Apr 2024)
Cumulative views and downloads (calculated since 11 Apr 2024)

Viewed (geographical distribution)

Total article views: 202 (including HTML, PDF, and XML) Thereof 202 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 28 May 2024
Download
Short summary
Marine stratocumulus cloud is a type of shallow clouds that covers the vast areas of Earth's surface. They play an important role in Earth's energy balance by reflecting solar radiation back to space. We used numerical models to simulate a large number of marine stratocumuli with different characteristics. We found that how the clouds develop throughout the day is affected by the level of humidity in the air above the clouds and how closely the clouds connect to the ocean surface.