Preprints
https://doi.org/10.5194/egusphere-2023-567
https://doi.org/10.5194/egusphere-2023-567
13 Jul 2023
 | 13 Jul 2023

The role of a low-level jet for stirring the stable atmospheric surface layer in the Arctic

Ulrike Egerer, Holger Siebert, Olaf Hellmuth, and Lise Lotte Sorensen

Abstract. In this study, we analyze the transition of a stable atmospheric boundary layer (ABL) with a low-level jet (LLJ) to a traditional stable ABL with a classic Ekman helix in the late-winter central Arctic. Vertical profiles in the ABL were measured with a hot-wire anemometer on a tethered balloon during a 15 h period in March 2018 in northeast Greenland. The tethered balloon allows high-resolution turbulence observations from the ground to the top of the ABL. The core of the LLJ was observed at about 150 m altitude, and its height and strength were associated with the temperature inversion. Increased turbulence was observed in the vicinity of the LLJ, but most of the turbulence does not reach down to the surface, thus decoupling the LLJ from the surface. Only when the LLJ collapses and the ABL again exhibits a more classical Ekman spiral, a coupling to the surface is re-established. Numerical simulations using an analytical model support these observations and allow conclusions to be drawn about the possible role of an LLJ in the advection of a passive tracer such as aerosol particles or moisture.

Ulrike Egerer et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-567', Anonymous Referee #1, 02 Sep 2023
    • AC1: 'Reply on RC1', Ulrike Egerer, 27 Oct 2023
  • RC2: 'Comment on egusphere-2023-567', Geraint Vaughan, 04 Sep 2023
    • AC2: 'Reply on RC2', Ulrike Egerer, 27 Oct 2023

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-567', Anonymous Referee #1, 02 Sep 2023
    • AC1: 'Reply on RC1', Ulrike Egerer, 27 Oct 2023
  • RC2: 'Comment on egusphere-2023-567', Geraint Vaughan, 04 Sep 2023
    • AC2: 'Reply on RC2', Ulrike Egerer, 27 Oct 2023

Ulrike Egerer et al.

Ulrike Egerer et al.

Viewed

Total article views: 345 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
250 76 19 345 10 8
  • HTML: 250
  • PDF: 76
  • XML: 19
  • Total: 345
  • BibTeX: 10
  • EndNote: 8
Views and downloads (calculated since 13 Jul 2023)
Cumulative views and downloads (calculated since 13 Jul 2023)

Viewed (geographical distribution)

Total article views: 334 (including HTML, PDF, and XML) Thereof 334 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 10 Dec 2023
Download
Short summary
Low-level jets (LLJs) are strong winds near the surface and occur frequently in the Arctic in stable conditions. Using tethered-balloon profile measurements in Greenland, we analyze a multi-hour period with an LLJ that later weakens and finally collapses. Increased shear-induced turbulence at the LLJ bounds mostly does not reach the ground until the LLJ collapses. An analytical model supports the hypothesis that a passive tracer can be advected with an LLJ and mixed down when the LLJ collapses.