Separation of Time Scales with fast rotation and weak stratification and some ideas for exascale computing

Thursday, April 14, 2011 - 9:00am - 10:00am
Keller 3-180
Beth Wingate (Los Alamos National Laboratory)
Earth's high latitudes stand to be among the first regions affected by
climate change issues due to changes induced by melting ice in the
Arctic and Antarctic. Motivated by gaining fundamental understanding
of ocean dynamics at high latitudes my collaborators and I have
derived new equations, based on the method of multiple scales
presented in Embid and Majda (1996,1998), that address the scale
separation between slow- and fast-time scale dynamics in the limit of
fast rotation while retaining order one affects due to stratification.
The new slow equations and their conservation laws describe the {sl
dynamics of Taylor-Proudman flows}. We also present numerical
results that support the theory and that show the spontaneous creation
of Taylor-Proudman columns. We also show recent measurements from the NSF Beaufort Gyre exploration program that show strong, deep columnar vortices with speeds as much as 30cm/s and which span the depth of the weakly stratified water column. The projection operators derived as a part
of these results have mathematical and numerical implications for the
development of time-stepping algorithms in next-generation exascale climate models.
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