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Sensitivity of Gravity‐Wave Momentum Flux to Moisture in the Mei‐Yu Front Systems
Author(s) -
Wang Yuan,
Zhang Lifeng,
Zhang Yun,
Peng Jun,
Yu Shiwang
Publication year - 2019
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 - 10.1029/2019gl083333
Subject(s) - gravity wave , momentum transfer , wave drag , stratosphere , momentum (technical analysis) , physics , flux (metallurgy) , atmospheric sciences , drag , convection , tropopause , gravitational wave , forcing (mathematics) , moisture , mechanics , geophysics , meteorology , optics , drag coefficient , astrophysics , materials science , finance , metallurgy , scattering , economics
The sensitivity of gravity‐wave momentum flux in the Mei‐Yu front systems to moisture is investigated via idealized simulations with various degrees of initial moisture content. Gravity waves generated in moist experiments result in net northward momentum flux and drag forcing, and the drag is indistinctive in the lower stratosphere near the tropopause but strengthens with height. As moisture content increases, the meridional flux intensifies remarkably in both physical and spectral space and extends to smaller spatiotemporal scales. However, the change of moisture has little effect on the selectivity of the strongest flux to relatively large scales and specific phase speeds. At slow phase speeds, the fanlike waves excited by the front are effectively coupled with the convective waves excited by the prefrontal moist convection, which leads to the weakening of the coupled wave flux.