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Unexpected climatological behavior of MLT gravity wave momentum flux in the lee of the Southern Andes hot spot
Author(s) -
Wit R. J.,
Janches D.,
Fritts D. C.,
Stockwell R. G.,
Coy L.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl072311
Subject(s) - mesopause , geology , momentum (technical analysis) , gravity wave , amplitude , atmospheric sciences , flux (metallurgy) , stratosphere , climatology , momentum transfer , gravitational wave , jet (fluid) , geophysics , physics , mesosphere , astrophysics , materials science , finance , quantum mechanics , metallurgy , optics , economics , scattering , thermodynamics
The Southern Argentina Agile MEteor Radar (SAAMER), located at Tierra del Fuego (53.7°S, 67.7°W), has been providing near‐continuous high‐resolution measurements of winds and high‐frequency gravity wave (GW) momentum fluxes of the mesopause region since May 2008. As SAAMER is located in the lee of the largest seasonal GW hot spot on Earth, this is a key location to study GWs and their interaction with large‐scale motions. GW momentum flux climatologies are shown for the first time for this location and discussed in light of these unique dynamics. Particularly, the large eastward GW momentum fluxes during local winter are surprising, as these observations cannot be explained by the direct upward propagation of expected large‐amplitude mountain waves (MWs) through the eastward stratospheric jet. Instead, these results are interpreted as secondary GWs propagating away from stratospheric sources over the Andes accompanying MW breaking over the Southern Andes.