File:Collected reprints - Atlantic Oceanographic and Meteorological Laboratories (and) Pacific Oceanographic Laboratories (1968) (20656430742).jpg

Title: Collected reprints / Atlantic Oceanographic and Meteorological Laboratories (and) Pacific Oceanographic Laboratories
Identifier: collectedreprin1976v1atla (find matches)
Year: 1968 (1960s)
Authors: Atlantic Oceanographic and Meteorological Laboratories; Pacific Oceanographic Laboratories; United States. Environmental Science Services Administration. Research Laboratories; Environmental Research Laboratories (U. S. )
Subjects: Oceanography Periodicals.
Publisher: Washington, D. C. : U. S. Dept. of Commerce, Environmental Science Services Administration, Research Laboratories : For sale by Supt. of Docs. U. S. G. P. O.
Contributing Library: Penn State University
Digitizing Sponsor: LYRASIS Members and Sloan Foundation

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Fig. 6. Thermal infrared image made off U.S. East Coast on May 12, 1975, showing Gulf Stream, meanders, and eddies in lighter shades; dark areas are cold clouds (NOAA, National Environmental Satellite Service). clearly visible; its instantaneous position may depart from the horizontal mean axis by amounts approaching 200 km, moving slowly (5- to 40-day periods) in comparison with the time (a few days) required to map the area with a satellite. The hope is that satellite altimetry will become sufficiently precise so that this dynamic topography, and hence surface current speed, can be deter- mined by using it \Kaula, 1970; Apel, 1972; Apel and Byrne, 19741. This requires that both the back- ground geoid and the topographic departures from it be determined with precisions approaching ±10 cm in the vertical. The requirement inextricably links dynamical oceanography and marine geodesy if such schemes are to be pursued. Figure 6 illustrates a NOAA 4 thermal infrared image off the northeastern U.S. coast with the warm water of the Gulf Stream in lighter shades (Koffler, 19751. Such imagery can be used to interpolate between the altimetry traces in order to obtain a more complete mapping of the Gulf Stream or simi- lar intense flows in regard to sur- face position and current speed. For upwellings it appears feasible to determine position, temperature, and areal extent of an upwelling event to 5 km within 1 to 2 days of its onset and to obtain estimates of the near-surface chlorophyll con- centration by using combined tem- perature and color imaging devices such as CZCS (NASA, 1975). Tides: Open Ocean and Shelf Deep-sea tides, being largely astronomically driven by the moon and sun, occur at precise frequen- cies, some five of which contain about 95% of the tidal energy. Their amplitudes in the open ocean are typically 0-1 m. Open ocean and shelf tides are difficult and time- consuming to measure, and their re- lationships to coastal tides are hard to establish. Worldwide deep-sea tidal measurements would aid in the theoretical understanding and prediction of tides at arbitrary loca- tions along the coastlines. By using precision altimetry in the way described earlier, it appears that one may determine tidal range to ±25 cm (relative to mean sea level) and phase to ±20° for diurnal and semidiurnal periods (Hen- dershott et ai, 19741. The required spacings are 25 km on continental shelves and 100 km globally. Ap- proximately 1 year of data is needed for the solution. Sea-Earth Interactions In the category of interactions be- tween the ocean and the solid earth is found such a wide diversity of features that no general discussion will suffice. Instead, each observa- ble will be taken up individually. Storm surge and wind setup along a coast. Storm systems pile up water ahead of them as they ap- proach a coastline from seaward. In the case of hurricanes this surge is often directly responsible for more damage and loss of life than the wind is. Hurricane surges are con- fined to a few tens of kilometers and a few hours of time during the land- fall; amplitudes can exceed 9 m. Wind setup is the accumulation of water along a coast due to long-term stresses such as trade winds; a typi- cal elevation is about 1 m. 618

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