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Observation and simulation of mountain wave turbulence above Iceland: Turbulence intensification due to wave interference

Wilms, Henrike and Bramberger, Martina and Dörnbrack, Andreas (2020) Observation and simulation of mountain wave turbulence above Iceland: Turbulence intensification due to wave interference. Quarterly Journal of the Royal Meteorological Society, 146 (732), pp. 3326-3346. Wiley. doi: 10.1002/qj.3848. ISSN 0035-9009.

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Official URL: https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.3848

Abstract

The High‐Altitude LOng Range research aircraft (HALO) encountered strong turbulence above Iceland at 13.8 km altitude on 13 October 2016. The generation of turbulence along the flight path is studied through numerical simulations in combination with the aircraft insitu observations. From the insitu observations, maximum energy dissipation rate values (cube root of the energy dissipation rate) of 0.39 m2/3 ·s-1 are obtained, which correspond to moderate to severe turbulence for a medium‐weight aircraft such as HALO. The turbulent region is characterized by observed large‐amplitude vertical wind fluctuations which coincide locally with a stagnation of the horizontal flow. The strong turbulence occurred downstream of and between the two Icelandic mountains Hofsjökull and Langjökull. High‐resolution numerical simulations, with realistic and idealized topography, show that the flow above these two nearby mountains is responsible for the observed turbulence. Vertically propagating hydrostatic mountain waves disperse horizontally in the region downstream and between Hofsjökull and Langjökull. There, both waves interfere and their superposition leads to enhanced amplitudes and, eventually, to convective instabilities. By comparing simulations with only one of the mountains to the simulation with both mountains, we infer that the wave interference can locally amplify the turbulence intensity by a factor of five and double the vertical extent of the turbulent region.

Item URL in elib:https://elib.dlr.de/135251/
Document Type:Article
Title:Observation and simulation of mountain wave turbulence above Iceland: Turbulence intensification due to wave interference
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Wilms, HenrikeDLR, IPAUNSPECIFIED
Bramberger, MartinaDLR, IPA und NCAR, Boulder, CO, USAUNSPECIFIED
Dörnbrack, AndreasDLR, IPAhttps://orcid.org/0000-0003-0936-0216
Date:2020
Journal or Publication Title:Quarterly Journal of the Royal Meteorological Society
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:146
DOI :10.1002/qj.3848
Page Range:pp. 3326-3346
Publisher:Wiley
ISSN:0035-9009
Status:Published
Keywords:gravity waves, turbulence, numerical modelling
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Middle Atmosphere
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Transport Meteorology
Institute of Atmospheric Physics
Deposited By: Volkert, Dr. Hans
Deposited On:09 Jun 2020 15:13
Last Modified:27 Nov 2020 15:55

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