The fluctuating longshore pressure gradient on the Pacific Northwest shelf: a dynamical analysis.

Abstract

The majority of papers on Pacific Northwest shelf dynamics emphasizes the relationship between longshore wind, and longshore velocity. However, attempts to illustrate a balance of momentum in the longshore direction have not been encouraging. It is demonstrated that the missing momentum is provided by the longshore pressure gradient force. The pressure gradient was estimated using tide gauge and atmospheric pressure data at stations separated by roughly 400 km. Seasonal and long term means from Hickey and Pola and, in some cases, nonseasonal monthly anomalies from Enfield and Allen were added to the sum of the tide gauge and atmospheric pressure data to form time series of total subsurface pressure. The pressure data were multiplied by an offshore decay factor to simulate coastal trapping. (from author's abstract)