The influence of the continental shelf on the tides of the Atlantic coast of the United States

Examination is made of the hypothesis that the tide along the eastern coast of the United States results from a co-oscillation of water over the Continental Shelf engendered by motion at the continental slope, the barrier against which the oceanic tidal wave is reflected . Using methods which are effective in analyzing tides in embayments, the range of tide and the time of high water over the continental slope have been estimated from data on the tide at the coast and from the topography of the off-lying shelf...

The processes determining the concentration of oxygen, phosphate and other organic derivatives within the depths of the Atlantic Ocean

The great oceans of the world all contain at intermediate depths less oxygen and more nitrate and phosphate than is found at either lesser or greater depths. This is one of the most marked physical features of the sea which must be attributed to the action of biological agencies. Those who have discussed this condition recently are agreed that it originates through the oxidation of organic matter derived primarily from the surface layers of the ocean, where alone the original synthesis of organic matter can occur. The condition obtaining at any depth is considered to depend upon the balance between the rate at which oxygen is removed from the water by respiratory and other metabolic processes and the renewal of oxygen in the layers in question by movements of the water. One group of investigators has emphasized the latter factor as the dominant one in determining the observed distribution of oxygen (Jacobsen, 1916; Dietrich, 1937; Wüst, 1935; Wattenberg, 1929, 1938). Oxygen content is reduced to the greatest extent at those depths in which the water is in minimal motion and hence the renewal of oxygen is least. Seiwell (1937) and Sverdrup (1938) have pointed out that this condition is not a necessity and is indeed in certain situations contrary to the apparent facts. They have shown that the observed distribution of oxygen may be accounted for by assuming various suitable relations between the rates at which oxidation occurs as a function of the depth and the rates of renewal by the circulation of water. These discussions appear to consider the state of the water to depend upon factors operative more or less locally and in situ. Specifically, oxidation is assumed to follow the sinking of organic matter from the surface to the depth in question in the discussions of Wattenberg (1937) and Seiwell (1937). The renewal of oxygen is assumed to depend on the horizontal circulation. Several considerations appear to have been given insuffcient weight in discussions of this subject. It is not at all clear why the depth of the oxygen minimum layer varies so greatly from place to place or what its relation is to the particular nutritive conditions in the sea's surface. Observations made in the relatively shallow water of the Gulf of Maine indicate that organic decomposition and oxidation take place for the most part not far from the sea surface. It seems not unreasonable to assume that the properties of the water which depend upon organic decomposition may have been determined primarily at a time when the water was relatively near the sea surface and that the water has subsequently moved into its observed position. The recent evidence, reviewed by Montgomery (1940), that mixing processes along surfaces of constant potential density may occur with great ease, even in the absence of directional flow, provides a convenient mechanism for establishing a distribution of oxygen and the products of organic activity at great depths which is dependent in large part on processes taking place much nearer the sea surface in remote regions. These considerations have suggested that the wellmarked evidence of decomposition which is observed at great depths in the central Atlantic Ocean may be due to the flow of water along surfaces of equal potential density from regions near the sea surface in high northern and southern latitudes rather than to the decay of organic matter derived directly from the overlying surface waters. This view requires that the characteristics of the water show a marked continuity in their distribution along layers of constant potential density, and that these layers emerge at or near to the sea surface in places suitable to produce the peculiar character of the layers in question. To test this possibility, data secured by the "Meteor," the "Discovery," and the "Atlantis" have been examined. The most illuminating information was secured from two north-south sections which together extend from Greenland to Antarctica. The South Atlantic was traversed by a section, made by the "Discovery" in April-May, 1931, extending along the thirtieth meridian from 57°36'S to 14°27'N ("Discovery" Reports, 1932). This is Section 2 of Clowes (1938). A section of the North Atlantic was constructed from the data secured by the "Atlantis" extending from 1°N to 34°N west of the fortieth meridian in March, 1932 (Stations 1158-1179), and from 39°N to 49°N near the fortieth meridian in September, 1935 (Stations 2485-2491), and by the "Meteor" (Stations 120-125) extending from 50°N to 58°N near the forty-fourth meridian, occupied in March, 1935 (Bull. Hydrographique, 1933, 1936). The data have been converted into suitable common units. Phosphate has been expressed as milligram-a toms phosphorus per cubic meter (γ-atoms P per liter) uncorrected for salt error. The function of the oxygen content which is of importance is the quantity which has disappeared from the water owing to metabolic processes. This has been approximated by assuming the water to have been saturated with air at the time it acquired its temperature and salinity at the sea surface and subtracting the recorded oxygen content from the value calculated on this assumption. The "apparent oxygen utilization" so obtained has been expressed as cubic centimeters per liter. In plotting the data for the sections, a rectangular grid on which latitude is represented horizon tally and sigma-τ is represented vertically has been chosen. Mon tgomery (1938) has shown that surfaces of equal sigma-τ are approximately of constant potential density. Consequently, on such a diagram the path of free movement by lateral mixing or flow is along horizontal lines. Any correlation of the distribution of a component of the sea water with potential density becomes at once apparent, if present. The surface of the sea and surfaces of any particular depth are represented by curved lines on the diagram. A grid of this type has been used by Spilhaus (1941) to distinguish different water types in the complex situation which exists at the margin of the Gulf Stream

The exchange of oxygen across the sea surface

In temperate latitudes the oxygen content of sea water near the surface varies with the season. This results because the solubility of oxygen in the water changes with its temperature and because of the unequal production and utilization of oxygen by organisms at different seasons. Both factors cause an exchange of oxygen across the sea\u27s surface. The present paper is an attempt to determine the magnitude of this exchange as it occurs in the Gulf of Maine and to evaluate the factors responsible

The tide in coastal waters

The tide in many straits and embayments between New York and the Bay of Fundy may be described by theoretical equations based on the interference of a progressive wave entering at one end of the reach with, in the case of straits, a second wave entering at the opposite end or, in the case of embayments, a second wave arising from the reflection of this wave from a barrier at the head of the embayment...

The tides of the waters of New England and New York

From the Preface: This book is written for the many intelligent people who work or play along the coast between Sandy Hook and the Bay of Fundy in the hope that it will give them a better understanding of matters which greatly influence the daily ordering of their activities. It may be of value to the serious student of the tides, at the beginning as an introduction to tidal theory and later as a summary of the tides on this particular coast. The stretch of coast considered and the off-lying ocean contain examples of practically all known tidal phenomena. The book is based for the most part on information given in the tide and current tables published by the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, formerly the Coast and Geodetic Survey. It is not intended to replace these tables if one would know what to expect at any particular place on any particular day. Rather, it attempts to explain why the tide locally is as it is and why it varies from place to place

Interference phenomena in the tides of the Woods Hole region

The relations of mean range of tide, time of high water, and time of slack water along Vineyard and Nantucket Sounds may be attributed to the interference of tidal waves entering the sounds from their opposite ends. Interference of the semidiurnal constituents is maximal in the neighborhood of Woods Hole where the great reduction of these constituents, relative to the diurnal constituents, results in a pronounced diurnal inequality in the range of successive tides at appropriate phases of the moon...

The analysis of tidal phenomena in narrow embayments

The tides of coastal embayments derive their energy from the ocean tides rather than from the direct action of lunar and solar gravitational forces. They are considered to be part of co-oscilating systems in which the period is determined by the tide in the outer sea, while the detailed character of the motion depends on the size and form of the enclosed basin (Defant, 1925; Doodson and Warburg, 1941). In narrow basins of simple form in which the influence of the earth's rotation is small, the motions resemble standing waves. Ideally, such waves are characterized by the simultaneous rise and fall of level on either side of a nodal line at which no change in elevation takes place. The elevation at high water increases with distance from the nodal line and slack water coincides with high and low water. The properties of tides due to standing waves may be deduced by assuming the motion to result from a primary progressive wave moving up the channel which undergoes complete reflection at a barrier. Mathematically, this situation may be treated as the interference of two identical progressive waves moving in opposite directions and so related that both waves are in phase at the barrier. This treatment of standing waves assumes the presence of total reflection, the absence of damping and the absence of effects of the earth's rotation. Since these conditions are not realized in natural tidal basins, the standing wave concept leads to oversimplification. In coastal embayments the most striking departure from the expectations of the standing wave concept is the discrepancy between times of high water and slack water, which may be great near the mouths of the larger bays and sounds. High water does not occur simultaneously within such enclosures but is earlier near the sea. Commonly, the nodal line is represented merely by a region in which the tidal range is small. These are effects which can be explained if damping of the primary and reflected waves by frictional or other effects is taken into account. According to these concepts, the problem of tidal behavior in embayments is to determine numerically the properties of the primary and reflected waves so as to account for the observed relations of amplitude and stream velocity of the actual tide and to correlate these numerical properties with the geographical form of the embayment. In the present paper an attempt is made to treat the tidal behavior in such a way that the observed changes in elevation and motion of the water along the path of the wave may be used to determine the distribution of phase of the primary and reflected waves along the channel and to measure the damping. The relations between the several aspects of a wave as it advances along a channel of uniform depth and width have been developed theoretically so as to show the times of high water and slack water, the range of the tide, and the phase relations of the primary and reflected waves along the channel for any degree of damping. By expressing the relationship of the several aspects of a reflected wave in a form in which the wave period is taken as the unit of time and distance is given in terms of the related phase changes, it is possible to eliminate the purely geographical dimensions and to obtain a wholly general description of the tide which may be used to indicate how any given channel distorts the behavior of the wave as it advances. In the case of irregular channels, in order to justify the application of relations deduced for uniform channels, in which the change in phase of the primary and reflected waves and their damping is proportional to the distance traveled and in which the velocity of the waves is constant, it is necessary to make the following assumptions: 1. That the effect of irregularities in cross section is to alter the velocity of the primary and reflected waves; i.e., to distort the geographical distribution of phase differences. 2.That damping is proportional to the phase change in the waves rather than to the distance traveled. 3. That the damping coeffcient, as defined, is constant along the length of the channel

Advanced manned space flight simulation and training: An investigation of simulation host computer system concepts

The findings of a preliminary investigation by Southwest Research Institute (SwRI) in simulation host computer concepts is presented. It is designed to aid NASA in evaluating simulation technologies for use in spaceflight training. The focus of the investigation is on the next generation of space simulation systems that will be utilized in training personnel for Space Station Freedom operations. SwRI concludes that NASA should pursue a distributed simulation host computer system architecture for the Space Station Training Facility (SSTF) rather than a centralized mainframe based arrangement. A distributed system offers many advantages and is seen by SwRI as the only architecture that will allow NASA to achieve established functional goals and operational objectives over the life of the Space Station Freedom program. Several distributed, parallel computing systems are available today that offer real-time capabilities for time critical, man-in-the-loop simulation. These systems are flexible in terms of connectivity and configurability, and are easily scaled to meet increasing demands for more computing power

Report to the Towns of Brookhaven and Islip, N.Y. on the hydrography of Great South Bay and Moriches Bay

Originally issued as Reference No. 52-26, series later renamed WHOI-.During the summer of 1950, The Woods Hole Oceanographic Institution conducted a study of the waters of Great South Bay for the Town of Islip, New York, with a view to seeking the cause of the decline of the oyster industry, which has deteriorated steadily during the past twenty years. The report of these studies was submitted in January 1951. The survey revealed two conditions which in combination appeared to be unfavorable to the oyster industry. One unfavorable condition was the local change in circulation occasioned by the opening of Moriches Inlet in 1931, which had increased the salinity of Bellport Bay, creating a condition which might well be detrimental to the production of seed oysters. Aside from this, it was concluded that little change had taken place in the salinity and tidal exchange of the central and western part of the bay during the past twenty years. The second unfavorable condition was the pollution of Great South Bay by wastes from the duck farms located along the Carmans River and the tributaries of Moriches Bay. Chemical studies indicated that the bay water is unusually rich in the products of decomposing organic matter. These materials appeared to arise from the mouth of the Carmans River and the tributaries of Moriches Bay, from which they are carried westward across Great South Bay. They provide nutriment for the growth of an unusually dense population of microscopic plants. Evidence existed that oysters do not feed properly on water containing such large concentrations of plant cells, and available statistics showed a clear correlation over a period of years between the condition of bay oysters and the numbers of plant cells in the water. Finally, the decline in oyster production has been closely paralleled by the growth of the duck industry, which increased fourfold during the period. In the report on the survey of 1950, it was pointed out that a number of questions had been revealed which were not anticipated when the field work was in progress and that these questions merited additional study. One of these related to the behavior of uric acid, the peculiar form in which birds secrete nitrogenous wastes, which promised to provide unambiguous evidence on whether the duck farms are the source of pollution. Another was the more detailed study of the circulation of Moriches Bay and its connection with Great South Bay through Narrow Bay, since this appeared to be the principal avenue of the pollution of Great South Bay. Finally, more detailed information was desired concerning the actual quantities of pollutants arising from the duck farms and of the alterations of its components by biological and other action upon introduction into the bay water. Before these additional studies could be undertaken, the problem acquired a new aspect be cause of the spontaneous closure of Moriches Inlet which occurred on May 15, 1951. While this terminated any possibility of increasing knowledge of the circulation between the bays as it previously existed, it afforded an opportunity to observe the effect of the opening on the condition of the bay waters. This information was of prime importance in view of the proposal to reopen and stabilize Moriches Inlet. Field parties visited the region on three occasions during the sumer. On July 12-14, 1951, a survey was made of the entire system of bays lying between the western extremity of Great South Bay and the Shintecock Canal. Between July 27 and August 5, studies were made of the chemical conditions in Moriches Bay and its approaches, and a detailed examination was carried out on the immediate conditions associated with the duck farms along the Terrell River. On September 24-29, an attempt was made to measure the exchange of water and associated pollutants between Moriches Bay and Great South Bay, and through the Quantuck Canal. On this occasion continuous observations were made at Smith Point and Beach Lane Bridge for a period of fifty hours, including four complete tidal cycles.The work conducted in 1951 was supported jointly by the appropriations made by the Towns of Brookhaven and Islip at the initiative of the Long Island Fishermen's Association