【报告人】Dr. Xiaochun Wang

【报告人单位】Joint Institute for Regional Earth System Science and Engineering, University of California

【报告时间】2012年9月6日（星期四）15:00

【报告地点】科研楼303会议室

Abstract

In the process of developing a real-time, data-assimilative coastal ocean forecasting system for Prince William Sound (PWS), Alaska, a three-domain nested model was configured for the region with the finest resolution of 1km. The circulation of PWS is influenced by local wind, large freshwater discharge and strong tides. A set of numerical experiments with different combinations of wind, run-off and tides are analyzed to untangle the influence of these forcing on the mean circulation in the central PWS and its seasonal variability. The mean circulation in the central PWS is generally characterized by a cyclonic cell. When forced only by the wind, the circulation is cyclonic in winter and fall and strongly anticyclonic in summer. The addition of freshwater run-off greatly enhances the eddy kinetic energy in PWS partly through near surface baroclinic instabilities. This leads to a much more intermittent circulation in the central Sound, with the presence of small-scale turbulence and a disappearance of the summer wind-forced anticyclonic cell. The addition of tides reduces the turbulence intensity, relatively to the experiment with run-off only. The generation of turbulent motions by baroclinic processes is lowered by tidal mixing and by modification of the exchange of PWS with Gulf of Alaska. Tides also tend to generate a mean cyclonic circulation in central PWS throughout the year. In addition to the analysis to untangle the roles of wind, run-off and tides in PWS, my presentation will also include a brief review of the real-time coastal ocean forecasting system.