Abstract
Abstract The relevance of barotropic instability for the observed low-frequency variability in the atmosphere is investigated. The stability properties of the shallow-water equations on a sphere are computed for small values of Lamb's parameter (F = α2Ω2/gHe) where a is the earth's radius, Ω its angular velocity, g gravity and He the equivalent depth. For small values of F these equations describe the horizontal structure of external and deep internal modes that are basically barotropic in the troposphere. The stability of simple zonal flows, as well as free and forced planetary Rossby waves, has been computed as a function of F. This is done numerically using a hemispheric spectral model with a T13 truncation. For F = 0 we have tried to interpret the numerical results by analytically computing the stability properties of the flow when only one triad is considered. The results show that for increasing F the critical amplitudes for instability decrease slightly, but in the area of instability both growth r...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
