Observed and Modeled Mountain Waves from the Surface to the Mesosphere near the Drake Passage - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Journal of the Atmospheric Sciences Year : 2022

Observed and Modeled Mountain Waves from the Surface to the Mesosphere near the Drake Passage

Christopher G. Kruse
  • Function : Author
M. Joan Alexander
  • Function : Author
Lars Hoffmann
  • Function : Author
Annelize van Niekerk
  • Function : Author
Inna Polichtchouk
  • Function : Author
Julio T. Bacmeister
  • Function : Author
Laura Holt
  • Function : Author
Petr Šácha
  • Function : Author
Corwin Wright
  • Function : Author
Kaoru Sato
  • Function : Author
Ryosuke Shibuya
  • Function : Author
Sonja Gisinger
  • Function : Author
Manfred Ern
  • Function : Author
Catrin I. Meyer
  • Function : Author
Olaf Stein
  • Function : Author

Abstract

Four state-of-the-science numerical weather prediction (NWP) models were used to perform mountain wave (MW)-resolving hindcasts over the Drake Passage of a 10-day period in 2010 with numerous observed MW cases. The Integrated Forecast System (IFS) and the Icosahedral Nonhydrostatic (ICON) model were run at Δx ≈ 9 and 13 km globally. The Weather Research and Forecasting (WRF) Model and the Met Office Unified Model (UM) were both configured with a Δx = 3-km regional domain. All domains had tops near 1 Pa (z ≈ 80 km). These deep domains allowed quantitative validation against Atmospheric Infrared Sounder (AIRS) observations, accounting for observation time, viewing geometry, and radiative transfer. All models reproduced observed middle-atmosphere MWs with remarkable skill. Increased horizontal resolution improved validations. Still, all models underrepresented observed MW amplitudes, even after accounting for model effective resolution and instrument noise, suggesting even at Δx ≈ 3-km resolution, small-scale MWs are underresolved and/or overdiffused. MW drag parameterizations are still necessary in NWP models at current operational resolutions of Δx ≈ 10 km. Upper GW sponge layers in the operationally configured models significantly, artificially reduced MW amplitudes in the upper stratosphere and mesosphere. In the IFS, parameterized GW drags partly compensated this deficiency, but still, total drags were ≈6 times smaller than that resolved at Δx ≈ 3 km. Meridionally propagating MWs significantly enhance zonal drag over the Drake Passage. Interestingly, drag associated with meridional fluxes of zonal momentum (i.e., u'υ' ¯ ) were important; not accounting for these terms results in a drag in the wrong direction at and below the polar night jet.

Dates and versions

insu-03726907 , version 1 (19-07-2022)

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Cite

Christopher G. Kruse, M. Joan Alexander, Lars Hoffmann, Annelize van Niekerk, Inna Polichtchouk, et al.. Observed and Modeled Mountain Waves from the Surface to the Mesosphere near the Drake Passage. Journal of the Atmospheric Sciences, 2022, 79, pp.909-932. ⟨10.1175/JAS-D-21-0252.1⟩. ⟨insu-03726907⟩
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