TY  - JOUR
AU  - Procházková, Zuzana
AU  - Kruse, Christopher G.
AU  - Alexander, M. Joan
AU  - Hoffmann, Lars
AU  - Bacmeister, Julio T.
AU  - Holt, Laura
AU  - Wright, Corwin
AU  - Sato, Kaoru
AU  - Gisinger, Sonja
AU  - Ern, Manfred
AU  - Geldenhuys, Markus
AU  - Preusse, Peter
AU  - Šácha, Petr
TI  - Sensitivity of mountain wave drag estimates on separation methods and proposed improvements
JO  - Journal of the atmospheric sciences
VL  - 80
IS  - 7
SN  - 0022-4928
CY  - Boston, Mass.
PB  - American Meteorological Soc.
M1  - FZJ-2023-01729
SP  - 1661–1680 
PY  - 2023
AB  - Internal gravity waves (GWs) are ubiquitous in the atmosphere, making significant contributions to the mesoscale motions. Since the majority of their spectrum is unresolved in global circulation models, their effects need to be parameterized. In recent decades GWs have been increasingly studied in high-resolution simulations, which, unlike direct observations, allow us to explore full spatiotemporal variations of the resolved wave field. In our study we analyze and refine a traditional method for GW analysis in a high-resolution simulation on a regional domain around the Drake Passage. We show that GW momentum drag estimates based on the Gaussian high-pass filter method applied to separate GW perturbations from the background are sensitive to the choice of a cutoff parameter. The impact of the cutoff parameter is higher for horizontal fluxes of horizontal momentum, which indicates higher sensitivity for horizontally propagating waves. Two modified methods, which choose the parameter value from spectral information, are proposed. The dynamically determined cutoff is mostly higher than the traditional cutoff values around 500 km, leading to larger GW fluxes and drag, and varies with time and altitude. The differences between the traditional and the modified methods are especially pronounced during events with significant drag contributions from horizontal momentum fluxes
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001022833400001
DO  - DOI:10.1175/JAS-D-22-0151.1
UR  - https://juser.fz-juelich.de/record/1006588
ER  -