PHYSICAL MATHEMATICS SEMINAR



TITLE:		CLIMATE CHANGE, ICE SHEETS AND 
		ANOMALOUS DIFFUSION: A VIEW FROM THE INSIDE OUT


SPEAKER:	ALAN REMPEL
		YALE UNIVERSITY



ABSTRACT:

Trace constituent recovered from the polar ice sheets provide the most detailed 
history of the earth's past climate.  Accurate interpretation of these hard-won archives
requires a careful treatment of all the processes that affect the climate proxies after they 
are emplaced.  The profiles that are eventually observed are modified by two key processes. 
Firstly, snow deposited on the ice-sheet surface deforms and flows under the weight of 
subsequent accumulation, leading to a gradual increase in depositional age with depth.  
Secondly, the climate proxies are subject to compositional diffusion.  Crucial to understanding 
the relative influence of these mechanisms is the realization that glacial ice is a two-phase medium 
with connected liquid-pathways that trace the grain intersections.  Through a careful examination
of the interaction between compositional diffusion and the phase relationships that determine the 
fraction of unfrozen liquid, homogenized models allow a quantification of the degree to which the
climate records are modified by post-depositional processes.  The predictions highlight the influence
of microphysical interactions on the interpretation of climate change and provide a rostrum for
Improved data analysis.

TUESDAY, OCTOBER 29, 2002
2:30 pm
Building 2, Room 338

Refreshments will be served at 3:30 PM in Room 2-349


Massachusetts Institute of Technology
Department of Mathematics
Cambridge, MA  02139