Case study of stratospheric gravity waves of convective origin over Arctic Scandinavia - VHF radar observations and numerical modelling

• Published in: Annales Geophysicae
• Main Authors: Réchou, Anne, Arnault, J., Dalin, P., Kirkwood, S.
• Other Authors: Laboratoire de l'Atmosphère et des Cyclones (LACy), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Swedish Institute of Space Physics Kiruna (IRF)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Arctic; Barents Sea; Kiruna; Esrange
• Online Access: https://hal.science/hal-00961368; https://hal.science/hal-00961368/document; https://hal.science/hal-00961368/file/Case_study_stratospheric_gravity_waves_convective_origin.pdf; https://doi.org/10.5194/angeo-31-239-2013

International audience Orography is a well-known source of gravity and inertia-gravity waves in the atmosphere. Other sources, such as convection, are also known to be potentially important but the large amplitude of orographic waves over Scandinavia has generally precluded the possibility to study such other sources experimentally in this region. In order to better understand the origin of stratospheric gravity waves observed by the VHF radar ESRAD (Esrange MST radar) over Kiruna, in Arctic Sweden (67.88◦N, 21.10◦E), observations have been compared to simulations made using the Weather Research and Forecasting model (WRF) with and without the effects of orography and clouds. This case study concerns gravity waves observed from 00:00 UTC on 18 February to 12:00 UTC on 20 February 2007. We focus on the wave signatures in the static stability field and vertical wind deduced from the simulations and from the observations as these are the parameters which are provided by the observations with the best height coverage. As is common at this site, orographic gravity waves were produced over the Scan-dinavian mountains and observed by the radar. However, at the same time, southward propagation of fronts in the Barents Sea created shorteriod waves which propagated into the stratosphere and were transported, embedded in the cyclonic winds, over the radar site.