QUASI-SYNOPTIC MONTHLY HYDROGRAPHY OF THE TRANSITION REGION BETWEEN COASTAL AND SLOPE WATER SOUTH OR CAPE COD, MASSACHUSETTS.
WOODS HOLE OCEANOGRAPHIC INSTITUTION MASS
Pagination or Media Count:
Detailed hydrographic conditions are enlarged upon in the area south of Nantucket and Marthas Vineyard at the boundary between Coastal and Slope Water at the edge of the continental shelf off Cape Cod, Mass. Five monthly cruises were made during a spring-summer season from May to September, 1958 to study detailed temperature and salinity distribution in both water masses at their boundary. Basic midsummer volumetric relations are given between water on the shelf and that in a parcel moved offshore, an inferred rate of formation of such parcels for July, the seasonal reduction in volume of cold shelf bottom water, and the monthly variation of areas between given isohalines in the halocline. Maximal observed salinity gradient is 2.4 000 per 10 meters. Parcel detachment is initiated by turbulence from internal waves shoaling in the density gradient of the halocline when the residual winter cooled shelf bottom water is in a state of quasi-inequilibrium. Tidal agitation then provides energy to move the parcel offshore. Instability and many inversions are observed in the collected data. Mixing between Coastal and Slope Water occurs on the larger scale of parcels of the former moving offshore into the latter and also by small scale exchange across the transition region separating the water masses. Regional development on the shelf edge thermal structure which effects offshore movement of the parcels is seasonal and is due to given occurrences in the shelf-slope area. Development both of them and an offshore body of water of temperature structure similar to it was extreme in 1958.
- Physical and Dynamic Oceanography
- Fluid Mechanics