Premium
Does Strong Tropospheric Forcing Cause Large‐Amplitude Mesospheric Gravity Waves? A DEEPWAVE Case Study
Author(s) -
Bramberger Martina,
Dörnbrack Andreas,
Bossert Katrina,
Ehard Benedikt,
Fritts David C.,
Kaifler Bernd,
Mallaun Christian,
Orr Andrew,
Pautet P.Dominique,
Rapp Markus,
Taylor Michael J.,
Vosper Simon,
Williams Bifford P.,
Witschas Benjamin
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd027371
Subject(s) - gravity wave , mesosphere , radiosonde , lidar , troposphere , stratosphere , infragravity wave , gravitational wave , atmospheric wave , tropopause , atmospheric sciences , environmental science , mesopause , amplitude , forcing (mathematics) , geology , geophysics , meteorology , physics , wave propagation , remote sensing , mechanical wave , longitudinal wave , quantum mechanics , astrophysics
On 4 July 2014, during the Deep Propagating Gravity Wave Experiment (DEEPWAVE), strong low‐level horizontal winds of up to 35 m s −1 over the Southern Alps, New Zealand, caused the excitation of gravity waves having the largest vertical energy fluxes of the whole campaign (38 W m −2 ). At the same time, large‐amplitude mesospheric gravity waves were detected by the Temperature Lidar for Middle Atmospheric Research (TELMA) located at Lauder (45.0°S, 169.7°E), New Zealand. The coincidence of these two events leads to the question of whether the mesospheric gravity waves were generated by the strong tropospheric forcing. To answer this, an extensive data set is analyzed, comprising TELMA, in situ aircraft measurements, radiosondes, wind lidar measurements aboard the DLR Falcon as well as Rayleigh lidar and advanced mesospheric temperature mapper measurements aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V. These measurements are further complemented by limited area simulations using a numerical weather prediction model. This unique data set confirms that strong tropospheric forcing can cause large‐amplitude gravity waves in the mesosphere, and that three essential ingredients are required to achieve this: first, nearly linear propagation across the tropopause; second, leakage through the stratospheric wind minimum; and third, amplification in the polar night jet. Stationary gravity waves were detected in all atmospheric layers up to the mesosphere with horizontal wavelengths between 20 and 100 km. The complete coverage of our data set from troposphere to mesosphere proved to be valuable to identify the processes involved in deep gravity wave propagation.