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Spiral gravity waves radiating from tropical cyclones
Author(s) -
Nolan David S.,
Zhang Jun A.
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 - 10.1002/2017gl073572
Subject(s) - geology , gravity wave , wavelength , advection , tropical cyclone , internal wave , amplitude , convection , gravitational wave , geophysics , meteorology , physics , climatology , optics , oceanography , astrophysics , thermodynamics
Internal gravity waves are continuously generated by deep moist convection around the globe. Satellite images suggest that tropical cyclones produce short‐wavelength, high‐frequency waves that radiate outward, with the wave fronts wrapped into tight spirals by the large differential advection of the sheared tangential flow. This letter presents new in situ observations of such waves from two sources: flight level data from research aircraft that show radial wavelengths of 2–10 km and vertical velocity magnitudes from 0.1 to 1.0 ms −1 and surface observations from a research buoy in the Pacific that indicate the passage of gravity waves overhead as tropical cyclones pass by at distances of 100 to 300 km. Numerical simulations are used to interpret these observations and to understand the broader horizontal and vertical structures of the radiating waves. The simulations suggest a correlation between wave amplitude and cyclone intensity, which could be used to make remote estimates of peak wind speeds.