Papers in Physical Oceanography and Meteorology
Permanent URI for this collection
Published by the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. Published originally as Massachusetts Institute of Technology Meteorological Papers (1930-1932), this collection contains papers from Vol .1 No. 1 to Vol. 10 No. 4 (1930-1948).
ISSN: 0198-6821
Browse
Browsing Papers in Physical Oceanography and Meteorology by Title
Results Per Page
Sort Options
-
BookAmerican air mass properties(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1933-06) Willett, Hurd C.In this paper the term Air Mass is applied to an extensive portion of the earth's atmosphere which approximates horizontal homogeneity. The formation of an air mass in this sense takes place on the earth's surface wherever the atmosphere remains at rest over an extensive area of uniform surface properties for a suffciently long time so that the properties of the atmosphere (vertical distribution of temperature and moisture) reach equilibrium with respect to the surface beneath. Such a region on the earth's surface is referred to as a source region of air masses. As examples of source regions we might cite the uniformly snow and ice covered northern portion of the continent of North America in winter, or the uniformly warm waters of the Gulf of Mexico and Caribbean Sea. Obviously the properties of an air mass in the source region will depend entirely upon the nature of the source region. The concept of the air mass is of importance not only in the source regions. Sooner or later a general movement of the air mass from the source region is certain to occur, as one of the large-scale air currents which we find continually moving across the synoptic charts. Because of the great extent of such currents and the conservatism of the air mass properties, it is usually easy to trace the movement of the air mass from day to day, while at the same time any modification of its properties by its new environment can be carefully noted. Since this modification is not likely to be uniform throughout the entire air mass, it may to a certain degree destroy the horizontal homogeneity of the mass. However, the horizontal differences produced within an air mass in this manner are small and continuous in comparison to the abrupt and discontinuous transition zones, or fronts, which mark the boundaries between air masses. Frontal discontinuities are intensified wherever there is found in the atmosphere convergent movement of air masses of different properties. Since the air masses from particular sources are found to possess at any season certain characteristic properties which undergo rather definite modification depending upon the trajectory of the air mass after leaving its source region, the investigation of the characteristic properties of the principal air mass types can be of great assistance to the synoptic meteorologist and forecaster. We owe this method of attack on the problems of synoptic meteorology to the Norwegian school of meteorologists, notably to T. Bergeron. Investigation of the properties of the principal air masses appearing in western Europe has been made in particular by O. Moese and G. Schinze. The purpose of this paper is to give the results of a similar investigation of the properties of the principal air masses of North America, and to comment on some of the striking differences which appear between conditions here and in Europe.
-
BookApplication of the distribution of oxygen to the physical oceanography of the Caribbean sea region(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1938-09) Seiwell, Harry RichardObservational data for this discussion were obtained principally during the two cruises of the oceanographic research ship, "Atlantis," to the Caribbean Sea March 7 to May 5, 1933 (stations 1487-1610) and February 2 to March 2, 1934 (stations 1935-2002). The oxygen determinations, carried out on board, have been published in Bulletin Hydrographique (1934, 1935) together with other hydrographic data. The Caribbean Sea region falls into two natural bathymetric subdivisions: a western, lying between Yucatan Channel and a ridge extending from Honduras to Haiti via Jamaica, designated in this paper as the "Cayman basin," and an eastern, between this ridge and the lesser Antilles, here designated as the "Caribbean basin". "Cayman basin" has been used by Parr (1937) and by Rakestraw and Smith (1937), and, while antedated by "Yucatan basin" (Krümmel, 1907) it seems that less confusion will arise if the term "Cayman" is used in this discussion. The "Atlantis" observations supply for the first time the necessary information for a detailed study of the distribution of oxygen in the Caribbean Sea region. The 1933 and 1934 observations are here used indifferently; such a procedure seemed desirable since the data are insuffcient for determination of annual or seasonal variations, particularly in view of the disturbing effect which may be caused by short period vertical oscillations of relatively large magnitude.
-
BookAverage monthly sea surface temperatures of the western North Atlantic ocean(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1947-05) Fuglister, Frederick C.This paper contains twelve charts of the North Atlantic Ocean west of the 60th meridian which show the average temperature of the surface water for each month of the year. Two additional charts show respectively the maximum and minimum values reached by the average temperature for any month. The next chart presents the yearly range, that is, the difference between the average temperature of the warmest and coldest months. The last chart of the series shows the depth of the virtually isothermal water during the summer and winter months.
-
BookCharacteristic weather phenomena of California : a regional analysis based on aeronautical weather observations(Massachusetts Institute of Technology, 1931) Byers, Horace R.During the fiscal year beginning July 1, 1928, the Daniel Guggenheim Fund for the Promotion of Aeronautics maintained an experimental meteorological service for the benefit of air transportation between San Francisco and Los Angeles. The system was designed as a first approach toward a model weather reporting organization for air traffic. Its main feature was the gathering of simultaneous weather observations from about 35 stations in Southern and Central California covering an area of, roughly, 65,000 square miles. The observation hours were 6.30 a.m., 8 a.m., 9.30 a.m., 11 a.m., 12.30 p.m., and 3.30 p.m., 120th meridian time. The regular Weather Bureau observations furnished additional data for 5 a.m. and 5 p.m. A description of the organization has been published by E. H. Bowie. Since the service was organized strictly for the purpose of informing airplane pilots of weather conditions over their routes and not with a view of furnishing a fertile field for meteorological investigations, certain instrumental readings which are important in meteorological research were not provided. Thus humidity observations are lacking, except as subsequently obtained from the few but more thoroughly equipped stations of the U. S. Weather Bureau, the U. S. Navy and the University of California. A series of airplane ascents made at the Naval Air Station at San Diego provided pressure, temperature and relative humidity observations from the upper atmosphere for part of the period investigated. Three pilot balloon stations were established by the Fund to supplement those of the Government, so that ample free air wind data are available. Non-professional part-time observers were employed at most of the stations. For this reason, inaccuracies are likely to have lessened the value of the reports. These errors occurred chiefly in the determination of cloud forms. When the uncertainties of cloud classification and the diffculties it presents even to the trained meteorologist are fully appreciated, the errors in these observations are not surprising. It is the opinion of the authors that the cloud forms herein recorded are for all practical purposes correct. During the year in which this service was conducted by the Fund, some interesting data were collected to add to the knowledge of meteorological conditions in California. This applies particularly to the movement of fronts and the development, distribution and dissipation of the persistent and frequent fogs in the area. Some of these results will be presented below.
-
BookCirculation in upper layers of southern North Atlantic deduced with use of isentropic analysis(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1938-08) Montgomery, Raymond B.Except for the presence in most localities of a shallow homogeneous surface layer and of a relatively homogeneous and deeper bottom layer, the oceans of the temperate and tropical regions are stratified and vertically stable at all depths. Due to the opacity of water for long-wave radiation and to the damping of vertical turbulence by the stability, there is no potent mechanism for altering the potential density of any water element below the layer of direct surface influences. Hence there can be no flow of major proportions across surfaces of constant potential density. For these reasons it is now generally accepted that flow takes place essentially parallel to these surfaces. It follows that the major sources for the water on each surface of constant potential density are to be found along its intersection with the sea surface in higher latitudes.
-
BookCloudiness and precipitation in relation to frontal lifting and horizontal convergence(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1943-08) Austin, James MurdochThe physical processes which result in the formation of clouds and the production of precipitation have been described by numerous meteorologists. The genetical classification has been summarized by Petterssen as follows: (1) Clouds and precipitation types which form in unstable air masses, (2) Clouds and precipitation types which form in stable air masses, (3) Clouds and precipitation types which form in connection with quasi-horizontal inversions in the free atmosphere, and (4) Frontal clouds and precipitation forms. In general, the procedure adopted for the forecasting of these meteorological elements can also be subdivided into the same four categories. Since the distribution of the elements in the atmosphere is never constant with time, the problem of forecasting cloudiness and precipitation is sometimes diffcult. A detailed discussion of qualitative and quantitative prognostic methods can be found in various standard meteorological texts. However, present methods are not entirely adequate and it is the aim of this investigation to contribute to the solution of the forecast problem. This study has been divided into two main sections, viz., (1) Clouds and precipitation types which occur at frontal surfaces as the result of frontal lifting, and (2) Clouds and precipitation types which occur within air masses as the result of horizontal convergence within the wind field. (1) Frontal Surfaces. In a recent study of fronts and frontogenesis, Petterssen and Austin have investigated the processes that tend to create wind shear, or vorticity, along fronts. It was found that, in general, an increase or decrease in shear is accompanied by a change in the vertical velocity field at a front. Since cloudiness and precipitation arise from the ascending velocities at frontal surfaces, the possibility of forecasting the change in horizontal shear at a front will be investigated. Furthermore, it has been shown that the vertical velocity of either air mass at a frontal surface can be determined from the velocity of the front and the horizontal wind velocity. The wind velocities in the free atmosphere can be obtained with a reasonable degree of accuracy, but the front velocity cannot always be evaluated with the same accuracy. Because it is important to determine the magnitude or at least the sign of the vertical velocities, a kinematical study will be made of the displacement of frontal surfaces. (2) Horizontal Convergence. In 1931 Giao published an explanation of the origin of clouds and precipitation in the vicinity of moving cyclones, without introducing the concept of frontal surfaces. Giao claimed that most condensation phenomena could be attributed to the cooling produced by local pressure changes and the horizontal convergence which arises from the meridional component of the wind velocity. The conclusions are conveniently summarized by Haurwitz, together with a short discussion of Giao's theory. Since some systems of clouds and precipitation types may result solely from convergence in the horizontal flow, an attempt wil be made to evaluate this effect quantitatively.
-
BookThe cycle of phosphorus in the western basin of the North Atlantic(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1935-04) Seiwell, Harry RichardThe importance of phosphorus for organic production in the sea appears to have been recognized first by Brandt (1899) and the earlier determinations of this element in the coastal seas of northern Europe (Brandt, 1920; Raben, 1920; Mathews, 1917) suggested a correlation between seasonal variation of phosphate and growth of phytoplankton. These earlier determinations were later shown to be too high (Atkins, 1926, a) and did not indicate the complete exhaustion of phosphate from the water, so it was not until several years later that Atkins (1923), employing the rapid and more accurate colorimetric ceruleo-molybdate method of Deniges, illustrated the complete dependence of algal growth on phosphate (in the English Channel) and thus established the foundation for modern studies of marine chemical fertility. The beginning of our knowledge of phosphate content of the open ocean may, as far as is known to me, also be attributed to Atkins (1926, a) and even though these early results were frequently somewhat vitiated by storing of the samples before analyses, they represented the order of magnitude of phosphate concentration in the sea. Within recent years phosphate determination has become a component part of the program of most deep sea investigations and much general information on its distribution and variation in the open ocean has been brought to light.
-
BookDiscussion and illustration of problems suggested by the analysis of atmospheric cross-sections(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1935-07) Willett, Hurd C.The preparation of atmospheric cross-sections, in which the fields of the various meteorological elements are represented in the vertical plane containing a number of synoptic aerological soundings, has long been a part of the technique applied to the investigation of problems in synoptic meteorology. However, owing to the lack of adequate observational material, the number of such cross-sections prepared in the past has been very small. The method was applied only in a few cases chosen for careful analysis and study. Consequently no uniform technique of analysis of such cross-sections has been developed, nor have the possibilities of this method of synoptic investigation received much attention. In the fall of 1933 the author decided that the possibilities of the cross-section method of synoptic representation warranted the systematic preparation and analysis of a large number of cross-sections. For this purpose a number of periods during which the synoptic maps seemed to indicate interesting atmospheric developments, and for which numerous aerological observations were available, were chosen from the maps of the preceding two or three years for detailed cross-sectional study. In all, ten periods of from two to six days each were chosen, a total of 36 days, entailing the preparation of about 90 cross-sections, and the use of about 400 aerological soundings.
-
BookThe distribution of oxygen in the western basin of the North Atlantic(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1934-08) Seiwell, Harry RichardThe distribution of dissolved oxygen in the sea is controlled by a combination of its physical, chemical and biological characteristics; on the one hand, the chemical and biological activities tend to vary the content of the dissolved gas whereas, on the other, the circulatory agencies tend to redistribute the oxygen and bring about equilibrium. The fact that there is a constant consumption of dissolved oxygen in the depths and that frequent supersaturation with oxygen occurs at or near the surface of the ocean was observed on the "Challenger" expedition (Dittmar, 1884). An explanation of the cause of supersaturation of oxygen, however, was not forthcoming until 1899 when Martin Knudsen suggested that it was caused by photosynthetic activities of vegetable plankton. The original oxygen content of ocean waters has been obtained from a-thin surface layer in contact with the atmosphere and as a product of photosynthetic activity. In modern concepts of oceanography it is a generally accepted fact that the water masses of the depths of the oceans have at some time and place been at the surface where under the influence of climatic conditions they acquired distinct temperature, salinity and oxygen characteristics. The sinking of the surface layers in the so-called regions of convergence and their ultimate distribution by means of quasi-horizontal and convectional currents results in the whole of the ocean basins being filled with water which has acquired its fundamental characteristics while under the influence of atmospheric conditions. From general knowledge of oceanic circulation, based on researches of Nansen (1912), Jacobsen (1929), Wüst (1928), etc., the water of the western basin of the North Atlantic is probably of several origins and consequently of different ages and oxygen contents. Thus, the deepest part of the whole basin, up to depths of 2000-1500 meters appears to contain water which, for the most part, originated at the surface in high North Atlantic latitudes. Lying on top of this deepest water there is, in the northern half of the region, what appears to be a mixture of it and other North Atlantic water, while in the southern half of the region there is at intermediate depths a mass of water which apparently originated at the surface in high latitudes of the South Atlantic.
-
BookDynamics of steady ocean currents in the light of experimental fluid mechanics(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1936-08) Rossby, Carl-GustafThe present investigation may be regarded as a part of a systematic effort to introduce into meteorology and physical oceanography methods and results which for a number of years have contributed to the rapid growth and increasing practical significance of experimental fluid mechanics. This science has recognized that the exact character of the forces controlling the motion of a turbulent fluid is not known and that consequently there is very little justification for a purely theoretical attack on problems of a practical character. For this reason fluid mechanics has been forced to develop a research technique all of its own, in which the theory is developed on the basis of experiments and then used to predict the behavior of fluids in cases which are not accessible to experimentation. In oceanography it has long been regarded as an axiom that the movements of the water are controlled by three forces, the horizontal pressure gradient, the deflecting force, and the frictional force resulting from the relative motion of superimposed strata. It is significant that thirty-five years of intensive theoretical work on this basis have failed to produce a theory capable of explaining the major features of the observed oceanic circulation below the pure drift current layer. The present investigation considers a force which has been completely disregarded by theoretical investigators although its existence has been admitted implicitly by practically everyone who has approached physical oceanography from the descriptive side, namely the frictional force resulting from large-scale horizontal mixing. The intro- . duction of this force permits us to see how motion generated in the surface layers may be diffused and finally dissipated without recourse to doubtful frictional forces at the bottom of the ocean.
-
BookThe effect of short period variations of temperature and salinity on calculations in dynamic oceanography(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1939-11) Seiwell, Harry RichardThis paper is a discussion of possible discrepancies in computations of ocean currents (based on horizontal variations of dynamic topography calculated from arbitrary deep lying reference surfaces), because of time variations of temperature and salinity at fixed depths in the sea (illustrated for a 24-hour period at "Atlantis" Station 2639). The results contained herein, while based chiefly on information from the western North Atlantic, are of general applicability, since time variations of the same order of magnitude have been observed over extensive areas of the Atlantic ocean. In selecting material for analysis of dynamic situations in the region concerned, consideration has been given only to those favorably located stations from which the structural features could most conveniently be obtained for illustrating the points in question.
-
BookThe electrical field induced by ocean currents and waves, with applications to the method of towed electrodes(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1954-11) Longuet-Higgins, M. S. ; Stern, Melvin E. ; Stommel, Henry M.The purpose of this paper is to discuss the nature of the electrical field induced in the ocean by particular types of velocity distribution. It is believed that these examples will be helpful in the interpretation of measurements by towed electrodes in the sea. The electrical field induced by waves and tidal streams, originally predicted by Faraday (1832), was first measured experimentally by Young, Gerrard and Jevons (1920), who used both moored and towed electrodes in their observations. Recently, the technique of towed electrodes has been developed by von Arx (1950, 1951) and others into a useful means of detecting water movements in the deep ocean. While the method has been increasingly used, the problem of interpreting the measurements in terms of water movements has become of great importance. Two of the present authors have made theoretical studies (Longuet-Higgins 1949, Stommel 1948) dealing with certain cases of velocity fields, and Malkus and Stern (1952) have proved some important integral theorems. There seems, however, to be a need for a more extended discussion of the principles underlying the method, and for the computation of additional illustrative examples. This is all the more desirable since some of the theoretical discussions published previously have been misleading.
-
BookFluid mechanics applied to the study of atmospheric circulations. I. A study of flow patterns with the aid of isentropic analysis.(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1938-12) Rossby, Carl-Gustaf ; Namias, Jerome ; Simmers, Ritchie G.This paper constitutes Part I of a report on certain investigations which have been in progress at the Massachusetts Institute of Technology during the past few years and which have been supported in part with funds provided by the Weather Bureau of the U. S. Department of Agriculture under the Bankhead-Jones Special Research Fund. The ultimate purpose of these investigations is to develop a sound physical model of the general circulation of the atmosphere, in the hope that an improved understanding of this process eventually may furnish valuable clues as to how the time range of our present daily weather forecasts may be extended and their quality be improved. In the past, the interpretation of the large-scale circulations of the atmosphere with the aid of the tools of classical hydrodynamics has suffered from the fact that these tools were designed for the study of thermodynamically inactive fluids, in which, furthermore, viscous or eddy stresses could be neglected. Through the work of V. Bjerknes and his students a good start has now been made towards the development of a science of hydrodynamics applicable also to thermodynamically active fluids, in which density changes are taking place as a result of non-adiabatic temperature changes. The removal of the second restriction-i.e., the development of hydrodynamic tools adapted to the study of fluids in which eddy stresses playa dominant role-has been accomplished mainly through the investigations of the Göttingen school of fluid mechanics. As yet, no synthesis of these two modern developments has been accomplished, although it is becoming increasingly clear that such a synthesis is needed before any headway can be made with the interpretation of the behaviour of the atmosphere. There has been a tendency on the part of meteorologists to assume that the effects of eddy stresses are restricted to a layer near the ground, and that the atmosphere above this layer behaves approximately as an ideal fluid. Even fairly elementary considerations show that a real understanding of atmospheric circulations becomes absolutely impossible on the basis of this assumption. A modest first attempt towards such a synthesis of the Norwegian and German developments will be attempted in these reports. It will be shown that the movements in the free atmosphere above the ground friction layer are affected by large-scale lateral mixing processes which produce shearing stresses acting across vertical planes, and one or two examples will be given to demonstrate that reasonable steady state solutions for the atmosphere can be obtained by taking this internal stress distribution into account. It will be shown, moreover, that the distribution of cold sources and heat sources in the free atmosphere is at least in part controlled by the stress distribution, which regúlates the location of ascending and descending movements.
-
BookFronts and frontogenesis in relation to vorticity(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1942-01) Petterssen, Sverre ; Austin, James MurdochSoon after the discovery of the polar front, it was realized that fronts were subject to processes which either increased or diminished their intensity. Thus, fronts may form in fields where the distributiori of the meteorological elements is continuous; and, in other cases, fronts may dissolve and develop into a field of continuous distribution of the various elements. The processes which lead to the formation of a front or the increase in intensity of an existing front, are called jrontogenetical processes; and the processes which lead to the dissolution of fronts are calledjrontolytical processes. In theoretical treatments of fronts it has been customary to simplify the problem by assuming that a frontal surface is a mathematical discontinuity, and doubts have been raised against the validity of this simplification. Petterssen has shown that both the dynamic and the kinematic boundary conditions that hold for perfect discontinuities hold also for layers of transition of finite thickness within which the meteorological elements vary continuously. We are, therefore, justified in treating frontal surfaces and fronts as either strict discontinuities or as finite layers of transition. Frontogenesis may therefore be defined as the process that tends to create a surface of discontinuity in the atmosphere. Whether or not this process results in a strict discontinuity is immaterial.
-
BookA generalization of the theory of the mixing length with applications to atmospheric and oceanic turbulence(Massachusetts Institute of Technology, 1932) Rossby, Carl-Gustaf
-
BookThe layer of frictional influence in wind and ocean currents(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1935-04) Rossby, Carl-Gustaf ; Montgomery, Raymond B.The purpose of the present paper is to analyze, in a reasonably comprehensive fashion, the principal factors controlling the mean state of turbulence and hence the mean velocity distribution in wind and ocean currents near the surface. The plan of the investigation is theoretical but efforts have been made to check each major step or result through an analysis of available measurements. The comparison of theory and observations is made diffcult by the fact that in most cases measurements have been arranged without the aid of a working hypothesis concerning the dynamics of the effect studied; thus information is often lacking concerning parameters essential to the interpretation of the data.
-
BookMeasurements of temperature and humidity in the lowest 1000 feet of the atmosphere over Massachusetts bay(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1946-11) Craig, Richard A.In the summer and fall of 1944, psychrometric measurements were made in the lowest 1000 ft of the atmosphere over Massachusetts Bay. They were designed to show vertical distributions of temperature and humidity in more detail than had any previous observations over a comparable height range. The measuring program was carried out under the general direction of Mr. Donald E. Kerr by members of the Radiation Laboratory, Massachusetts Institute of Technology, in connection with studies concerning the propagation near the sea surface of radio waves of the order of centimeters or a few meters in length. The meteorological measurements were desired because they yielded information about vertical distributions of refractive index of air for radio frequencies. The vertical distribution of refractive index is of great importance in the propagation problem (Sheppard, 1946), that in the lowest 1000 It being of primary significance for the study at the Radiation Laboratory.
-
BookMeasurements of the vertical water vapor transport and distribution within unstable atmospheric ground layers and the turbulent mass exchange coefficient(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1952-12) Bunker, Andrew F.The series of observations described in this report were planned with the double purpose of measuring the evaporation and transport of water vapor from the ocean into an unstable atmosphere, and of studying the diffusion processes operating in air of this stability class. Measured values of the evaporation from ocean surfaces were conspicuously absent from the meteorological literature until Craig and Montgomery (1949) published values for hydrostatically stable air. The present set of measurements extends our knowledge to include evaporation into a hydrostatically unstable air mass. In addition to evaporation values at the surface, net transports of water vapor at many levels up to 2000 meters have been measured.
-
BookThe meteorological airplane ascents of the Massachusetts Institute of Technology. Part I. On the technique of meteorological airplane ascents. Part II. Aircraft instruments in meteorological flying(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1934-08) Lange, K. O. ; Draper, C. S.The aerological flights at Boston are part of the general research program of the Meteorological Division of Massachusetts Institute of Technology, which program since 1929 has been directed especially toward the study of American air masses and fronts. Recently, some results of these studies were published by Willett, who based his investigations on a series continuous over three years of mornìng and evening weather maps, analyzed at the Institute, together with upper air soundings from the United States Weather Bureau stations at Dallas, Omaha, Chicago, Groesbeck, Atlanta and from the United States Navy at Seattle, Anacostia, Pensacola and San Diego. These upper air data facilitated the determination of the properties of the air masses and so proved of inestimable value for the study. But the use of the data also showed that improvement both in the number of stations and in the quality of observations was highly desirable. Ascents in the northeastern part of the United States were lacking. Knowledge of the vertical structure of air masses reaching this region, however, is of special interest in forecasting for this densely populated district. For these reasons and since the direct comparison of actual local weather developments with upper air conditions is also con- sidered to be very valuable, the Institute started its own airplane station at Boston. In addition to "regular" ascents at the time of the morning surface observations, special flights were made when particularly interesting weather situations prevailed. On a number of days series of ascents were carried out to obtain cross sections through fronts passing over Boston. Other special flights were made to obtain information on atmospheric turbulence. For this same purpose and also in order to study the diurnal changes of temperature in the lowest 5,000 feet, several series are planned of a number of comparatively low altitude flights at short intervals throughout the day.
-
BookThe minimum oxygen concentration in the western basin of the North Atlantic(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1937-05) Seiwell, Harry RichardWith the advance in knowledge of oceanic circulation there now exists a demand for additional identifying properties which will serve to trace the origin and movements of water masses in the sea, and to check earlier conclusions based entirely on temperature and salinity distribution. Of all the known identifying properties (except temperature and salinity) oxygen appears to be the most useful, not only because of the ease with which it can be accurately measured at sea, but also because of the large amount of data available on its distribution in the open ocean.