The Effects of Atomic Radiation on Oceanography and Fisheries (1957) / Chapter Skim
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TRANSPORT AND DISPERSAL OF RADIOACTIVE ELEMENTS IN THE SEA
TRANSPORT AND DISPERSAL OF RADIOACTIVE ELEMENTS IN THE SEA
Pages 43-51
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From page 43... ...
Some evidence of the rapidity of vertical mixing in the upper layer is given by Folsom (Revelle, Folsom, Goldberg and Isaacs, 1955) , who observed that when fission products were introduced at the surface in an area where the surface layer was about 100 meters thick, the lower boundary of the radioactive water reached the bottom of this layer in about 28 hours.
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From page 44... ...
When radioactive materials are introduced into the near-surface layer, they are transported away from the area of introduction by surface currents. These currents extend, in general, through the entire depth of the upper layer and seem to be driven, directly or indirectly, by the wind.
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From page 45... ...
Exchange between near-surface and intermediate waters Since the surface layer is separated from deeper waters by a layer of rapid density increase, and hence of great stability, vertical transfer of materials across this layer by eddy diffusion must be much less rapid than is vertical diffusion in the upper layer. Thus radioactivity introduced at the surface by fallout may remain in the upper layer for a long time and be diluted by only a small part of the total volume of the sea.
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From page 46... ...
In a simple sense, the persistent trade winds blowing parallel to or offshore develop an offshore component of transport in the surface waters, and deeper waters upwell to maintain the volume continuity. Upwelling may also occur along other coasts when the winds are suitable.
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From page 47... ...
It is clear that the ultimate distribution in coastal areas of radioactive materials added to the sea would depend on the location of the release, the vertical distribution of radioactivity and density in the area of release, the length of time required for the transport to the coastal area or estuary, and the location of the source sea water which provides for the counter drift. The number of variables involved makes it difficult to discuss the effects in general terms, but it is worthwhile to note that the circulation in coastal areas is rapid, and water bathing the North Atlantic beaches is not uncommonly 90 per cent sea water even off large rivers such as the Hudson and Delaware.
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From page 48... ...
The general uniformity of temperature and dissolved substances in deep water suggests that deep currents are very slow, perhaps at most a few centimeters per second. But deep currents cannot be computed by the geostrophic method because only relative velocities can be thus obtained.
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From page 49... ...
The problem of the disposal of radioactive wastes in the deep sea has stimulated the oceanographer's natural curiosity as to the rate of this exchange. The North Atlantic receives surface waters from the South Atlantic and loses deep water to the South Atlantic.
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From page 50... ...
Present estimates of the age of deep waters are based primarily on measurements in the North Atlantic and on geochemical calculations for the entire world ocean. That the deep circulation of the Pacific is significantly slower than that of the Atlantic is suggested by the apparent absence of regions of deep and bottom water formation in the Pacific and the relatively high nutrient salt content and low dissolved oxygen content of deep Pacific waters.
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From page 51... ...
1950. Atlas of surface currents, northwestern Pacific Ocean.
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