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Linear advection characteristics of a variable resolution global spectral method on the sphere

Presented by: 
Janakiraman Subburathnam Centre for Development of Advanced Computing, (C-DAC)
Date: 
Tuesday 25th September 2012 - 09:50 to 10:15
Venue: 
INI Seminar Room 1
Session Title: 
Advection Session
Abstract: 
Advection experiments are conducted with a variable resolution global spectral method on the sphere. The variable resolution grid has finer resolution over the tropics and the resolution decreases smoothly as we move towards the poles [Janakiraman et al (2012) ]. An Eulerian formulation of the linear advection is used to for the spectral discretization. Near dispersion-free advection is achieved on the high resolution tropical belt. The transport across homogeneous resolution regions produce very less dispersion errors. Transport over the poles result in severe grid representation errors. It is shown that increasing the resolution over the reatly reduces this error. Transport of a feature from apoint close to poles but not over it does not produce such representation errors. A comparison of time-schemes such as 4-th order Runge-Kutta method, Magazenkov scheme and Leap-frog scheme for the advection experiment is also presented.

Reference(s) : S. Janakiraman, Ravi S Nanjundiah and A.S. Vasudeva Murthy, A novel variable resolution global spectral method on the sphere, Vol. 231, No. 7, pp 2794--2810, 2012.
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Presentation Material: 
University of Cambridge Research Councils UK
    Clay Mathematics Institute The Leverhulme Trust London Mathematical Society Microsoft Research NM Rothschild and Sons