Preprints
https://doi.org/10.5194/egusphere-2022-1444
https://doi.org/10.5194/egusphere-2022-1444
 
24 Jan 2023
24 Jan 2023
Status: this preprint is open for discussion.

A simple model to assess the impact of gravity waves on ice crystal populations in the tropical tropopause layer

Milena Corcos1, Albert Hertzog1, Riwal Plougonven2, and Aurélien Podglajen3 Milena Corcos et al.
  • 1Laboratoire de Météorologie Dynamique/IPSL, Sorbonne Université, Paris, France
  • 2Laboratoire de Météorologie Dynamique/IPSL, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
  • 3Laboratoire de Météorologie Dynamique/IPSL, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France

Abstract. The role of gravity waves on microphysics of tropical cirrus clouds and air parcel dehydration was studied using the combination of Lagrangian observations of temperature fluctuations and a 1.5 dimension model. High frequency measurements during isopycnal balloon flights were used to resolve the gravity wave signals with periods ranging from a few days to 15 min. The detailed microphysical simulations with homogeneous freezing, sedimentation and a crude horizontal mixing represent the slow ascent of air parcels in the Tropical Tropopause Layer. A reference simulation describes the slow ascent of air parcels in the tropical tropopause layer, with nucleation occurring only below the cold point tropopause with a small ice crystals density. The inclusion of the gravity waves modifies drastically the low ice concentration vertical profile and weak dehydration found during the ascent alone, with the increased ice crystal number and size distribution agreeing better with observations. Numerous events of nucleation occur below and above the cold point tropopause, efficiently restoring the relative humidity over ice to equilibrium with respect to the background temperature, as well as increase the cloud fraction in the vicinity of the cold-point tropopause. The corresponding decrease in water vapor is estimated at 2 ppmv around the cold point tropopause.

Milena Corcos et al.

Status: open (until 07 Mar 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Milena Corcos et al.

Milena Corcos et al.

Viewed

Total article views: 67 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
51 13 3 67 0 0
  • HTML: 51
  • PDF: 13
  • XML: 3
  • Total: 67
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 24 Jan 2023)
Cumulative views and downloads (calculated since 24 Jan 2023)

Viewed (geographical distribution)

Total article views: 67 (including HTML, PDF, and XML) Thereof 67 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 26 Jan 2023
Download
Short summary
The role of gravity waves on tropical cirrus clouds and air parcel dehydration was studied using the combination of Lagrangian observations of temperature fluctuations from superpressure balloons and a 1.5 dimension model. A reference simulation of a slow ascent of air parcels in the tropical tropopause layer showed nucleation occurring only below the cold point with a small ice crystals density. Adding gravity waves drastically increases ice crystal number and fits better to observations.