MONDAY, DECEMBER 4, 2006

TOPOLOGY SEMINAR

TIME: 10:10 a.m. - 11:00 a.m.
ROOM: Ayres Hall 309B
SPEAKER: Professor Morwen Thistlethwaite
TITLE: Introduction to hyperbolic structures on 3-manifolds IV


DE/APPLIED AND COMPUTATIONAL MATH SEMINAR

TIME: 3:35 p.m. ­ 4:25 p.m.
ROOM: Ayres Hall 309A
SPEAKER: Professor Zhenghui Xie, Institute of Atmospheric Physics
Chinese Academy of Sciences
TITLE: A moving boundary problem and its applications to land-atmosphere interactions

ABSTRACT:
Changes in surface runoff, groundwater and base flow due to climate change feed back to influence climate by changing fluxes of energy, moisture, and momentum between land and atmosphere, while the current class of land process models used with climate models parameterizing these fluxes in detail neglect the dynamic variability of the groundwater table. The dynamic representation of the groundwater table can be reduced to a moving boundary problem, and numerical models are developed to dynamically simulate the movement of liquid moisture flow and groundwater level in saturated-unsaturated system by using the mass-lumped finite element method and through certain mathematical transformations. The groundwater model with a new surface runoff parameterization, and a base flow model with storage and recharge is coupled to the community land model (CLM2.0) to represent interactions between climate, and surface water and groundwater, which is called CLM-IAG. To test and validate the land surface model with the groundwater component CLM-IAG and the impacts of including the three hydrological process models mentioned above, simulations by CLM-IAG and CLM show that the land surface model with representation of groundwater table dynamics CLM-IAG can simulate changes of groundwater table and variations of soil moisture and soil temperature quite well in some extent compared with the observations. To test the applicability of the land surface model CLM-IAG on the global scale, a ten year off-line simulation by the CLM-IAG with the global forcing data is performed, which shows that it has potential applications on interactions between land and atmosphere.

TUESDAY, DECEMBER 5, 2006

THE ORAL SPECIALTY EXAMINATION OF MR. TIM CLAYTON
TIME: 4:00 p.m.
ROOM: Ayres Hall 309A
COMMITTEE: Professors: Lenhart (chair), Gross and Simpson.