Observations of a California Current Jet Meandering off the Continental Shelf into a Deep Ocean Region

During early August 2006, a series of meteorological and near surface oceanographic measurements (0-200 m) were conducted from R/V Mt. Mitchell in an ocean region in the northeast Pacific, near 46° N, 126° W, west of the North America continental shelf break, and in 2000 m deep water. The test region was roughly 20 nmi west of the main path of the California Current, however, observations of a jet meandering off the California Current and intruding into the deep water test region were captured in both in situ measurements from the R/V and remote satellite observations of the ocean surface. The horizontal boundaries of the jet intrusion in the test region are apparent in both in situ and satellite remote sensed temperature measurements as well as in ocean currents measured by ADCP and Lagrangian style surface drifters. Temperature and salinity profiles show waters associated with the jet are significantly cooler and slightly fresher than the ambient water in the test region. After initial observations of the intruding jet, measurements in the test region continued for the duration of seven days. Winds were initially relatively calm, in the 5-12 knot range, but after about three days, winds suddenly increased to over 20 knots, and high winds (NNW) persisted for three days. A corresponding increase in near surface, wind driven circulation was observed, moving approximately 90 degrees to the right of the wind direction.