JpGU-AGU Joint Meeting 2017

Presentation information

[EJ] Oral

A (Atmospheric and Hydrospheric Sciences) » A-OS Ocean Sciences & Ocean Environment

[A-OS29] [EJ] Dynamics of oceanic and atmospheric waves, vortices, and circulations

Tue. May 23, 2017 9:00 AM - 10:30 AM 302 (International Conference Hall 3F)

convener:Ryo Furue(APL/JAMSTEC), Yukiharu Hisaki(Faculty of Science, University of the Ryukyus), Humio Mitsudera(Institute of Low Temperature Science, Hokkaido University), Norihiko Sugimoto(Keio University, Department of Physics), Chairperson:Humio Mitsudera(Institute of Low Temperature Science, Hokkaido University), Chairperson:Hidenori AIKI(Nagoya University), Chairperson:Ryo Furue(APL/JAMSTEC)

10:15 AM - 10:30 AM

[AOS29-06] Formulation and application of phase-independent evergy conversions for quasi-geostrophic eddies

*Takaya Koutarou1 (1.Kyoto Sangyo University)

Keywords:quasi-geostrophic eddy, energy conversion, low-frequent variability in the extra-tropics

Estimating energy conversions could be useful to clarify dynamics of low-frequent variability of quasi-geostrophic disturbances. Energy conversion terms are composed of quadratic terms in disturbance amplitudes and shear terms of basic flows, so that they can mean energy conversions between disturbance fields and the basic flows. The quadratic terms in the energy conversions are usually expressed by the velocities of the disturbances, such as momentum transports u’v’, so that they inherently include an oscillatory component of one-half wave-length. Therefore, in traditional forms of the energy conversions, phase-averaging such as time-averaging should be needed to express energy-conversion distributions in the phase-independent forms.
In this study, a new formulation of energy conversions for quasi-geostrophic eddies is proposed under an assumption that a eddy is almost a plane wave in the WKB sense. Because of a phase-independent form, the new formulation can be applicable to estimating energy conversions for stationary eddies or snapshot of transient eddies. Actual applications of the new form of the energy conversions to the data analysis will also be given.