August 22, 1994 - Nor'easter Trish
At the end of each summer, temperatures are typically like those in figure a, with upwelling along the coast, and temperature cross sections with cold 10 C water at the bottom and warmer 20 C water at the top. Usually in late summer, a storm arrives and mixes the entire water column. In 1994 this storm hit on August 22. This nor'easter type storm mixed the water from top to bottom resulting in colder surface water and a virtually homogenous cross section as in figure b.
Figure c contains wind data from the met - tower at RUMFS and S4 current meter data. The S4 is located on the ocean bottom at Station 9 (between A1 and A2). The center of this storm passed over the field station and research area betweenAugust 22-23. This resulted in an increase in wind speed, wave height, bottomcurrent speeds, and bottom temperatures. The increase in bottom temperatures was due to mixing of the warmer surface water. A 2.5 degree temperature difference replaced the 10 degree difference seen only a few days before.
Figure d contains two near bottom current velocity profiles from before and after the storm. The green circles are actual current speeds at the specified height. Theoretically, the speed of a current increases logarithmically as one moves up from the sea floor. These logarithmic plots of actual data serve as proof of this theory. Zo (where the pink line intersects the y axis) is where the velocity becomes zero cm/sec. During the storm, Zo is higher, indicating an increase in bottom roughness.