Extended Abstract (516K)3.4
The effect of the stability of the atmospheric boundary layer on the coastal upwelling over the California coast
Adam Kochanski, DRI, Reno, NV; and D. Koracin, G. Beg Paklar, and C. E. Dorman
One of the most interesting phenomena that is evidence of the linkage between the atmospheric and the ocean dynamic is the coastal upwelling. Even now, after many years of studies, the contribution of the along-shore wind stress and the positive wind stress curl to the generation of coastal upwelling is not clear. Additionally, the coastal upwelling is affected by the stability of the atmospheric boundary layer. The drop in the sea surface temperature, induced by rising of the cold water during upwelling, enhances the atmospheric stability and inhibits momentum transfer from the atmosphere to the ocean close to the shore. The warmer water offshore reduces the stability of the atmospheric boundary layer and enhances the wind stress. These two mechanisms induce the positive wind stress curl that may additionally enforce the upwelling process even for a uniform wind field across the shore. In this study we investigate the ocean response to the atmospheric stability, by running the coupled The Fifth-Generation NCAR / Penn State Mesoscale Model (MM5) and The Princeton Ocean Model (POM). As a base line we perform a simulation assuming neutral stratification. For this case we use a bulk formula for the computation of the wind stress. In the next stage we perform a similar simulation but compute the wind stress based also on the heat and moisture fluxes exchanged across the sea-air interface. The comparison of the results shows what part of the wind stress curl is a result of the difference in the stability of the atmospheric boundary layer, and how these differences influence the ocean upwelling.
Session 3, Advancing our modeling capabilities/tools: US West Coast
Tuesday, 11 September 2007, 2:15 PM-5:00 PM, Boardroom
Previous paper Next paper
Recorded presentation