• Equilibrium and Transport in a Fully Ionized Gas

      Brittin, Wesley Emil (Geophysical Institute at the University of Alaska, 1957-04)
    • An evaluation of auroral all-sky camera observations

      Davis, T. N.; Deehr, C. S.; Leinbach, H. (Geophysical Institute of the University of Alaska, 1960-03)
      From photometric, all-sky camera, and visual observations of a moderate auroral display, it is found that the all-sky camera compares favorably with the visual observer in detecting and recording auroral forms. The visual observer can make instantaneous observations and so can detect rapid changes and auroral forms lasting only a few seconds, whereas the poorer time resolution of the all-sky camera prevents it from recording very short-lived phenonema. However, the ability of the all-sky camera to accurately record the shape and intensity of the majority of auroral forms allows it to yield more precise and complete information about these aspects of auroral morphology than is normally obtained through visual observation.
    • Evaluation of chemical methods for the determination of atmospheric ozone

      Mukherjee, Nalin R. (Geophysical Institute at the University of Alaska, 1952-11-15)
      Since the concentration of the ozone in the atmosphere near the earth's surface is of the order of 10 gm. per gm. of air, the quantitative determination of this ozone by chemical methods is rather difficult. Therefore, the different methods have been evaluated to determine the best, all conceivable precautions being taken into account. The chemical methods may be classified into two groups --Titer Methods and Spectro-chemical Methods. Among the former, two; namely, the Thiosulphate and Arsenite Methods, have been proposed and used. For the low concentration of ozone in the atmosphere near the earth 's surface, the Thiosulphate Method is found to give unreliable results due to the instability of the thiosulphate solution as well as to various side reactions which could not be controlled. The arsenite solution, however, is much more stable than the thiosulphate solution. Side reactions are very few and can largely be controlled. Reliable results can be obtained by the Arsenite Method when employing proper precautions. The oxidants and other interfering substances in the atmosphere present serious problems. Some oxidants behave like ozone as far as the reactions with the chemical reagents are concerned. Their occurrence in the atmosphere and their effects on the chemical reagents used for the quantitative determination of the atmospheric ozone are discussed in detail. Suggestions are made for their elimination from the atmosphere without affecting the ozone concentration.
    • Experiment Luxembourg

      Rumi, G. C.; Little, C. G. (Geophysical Institute at the University of Alaska, 1958-12)
      The earlier orbits and ephemerides for the Soviet satellites were not sufficiently accurate to be very useful in making observations in Alaska. Extrapolations from our own observations gave better predictions. This merely pointed out the fact that rough observations of meridian transits at high latitudes will give better values of the inclination of the orbit than precision observations at low latitudes. Hence, it was decided to observe visually the meridian transits estimating the altitude by noting the position with respect to the stars or using crude alidade measurements. The times of the earlier observations were observed on a watch or clock and the clock correction obtained from WWV. Later the times were determined with the aid of stop watches, taking time intervals from WWV signals. This rather meager program of optical observations of the Soviet satellites was undertaken to give supplementary data for use of the radio observations, and particularly to assist in the prediction of position of the satellite so that the 61-foot radar of Stanford Research Institute could be set accurately enough to observe it (the beam width at the half-power points is about 3°). This report contains primarily the visual observations made at the Geophysical Institute by various members of the staff, and a series of observations by Olaf Halverson at Nome, Alaska. In addition there is a short discussion of the geometry of the trajectory, the illumination of a circumpolar satellite, and a note on the evaluation of Brouwer's moment factors.
    • Experiment Luxembourg, Scientific Report No. 2

      Rumi, G. C. (Geophysical Institute at the University of Alaska, 1959-05)
    • Experiment Luxembourg, Scientific Report No. 3

      Rumi, G. C. (Geophysical Institute at the University of Alaska, 1960-02)
    • Experiment Luxembourg, Scientific Report No. 4

      Rumi, G. C.; Benson, R. F. (Geophysical Institute at the University of Alaska, 1960-12)
      Experiment Luxembourg was designed to measure the electron density and electron collision-frequency as a function of height in the D region over College, Alaska using the technique of radio-wave interaction. A block diagram, which includes all the equipment necessary for the actual operation of the experiment, is described and illustrated in detail. The major parts of the system are: the disturbing transmitter operating on 17.5 Mc/s and using a 4x4 array of Yagi antennas, the wanted transmitter operating on ~ 5 Mc/s and using a circular polarization unit with 4 dipoles arranged in a quadrangle, a similar circular polarization unit and antenna for 5 Mc/s at the receiving site, and the delicate receiving system which detects a cross-modulation of 1x10 -4 for a one volt input signal. Some values of electron density and collision-frequency have been obtained and will be discussed in following publications.
    • An HF sweep frequency study of the arctic ionosphere

      Bates, Howard F. (Geophysical Institute at the University of Alaska, 1961-04)
      Observations made during 1958 and 1959 using a sweep frequency, HF, oblique sounder located at College, Alaska, are discussed, and selected groups of echoes are illustrated. Groundscatter is the predominant echo type observed on mid-latitude backscatter records, but this is not true in the high latitudes. The majority of the scatter echoes from soundings toward geomagnetic north were direct F region scatter of two main types - IF and constant range echoes. These same echo types were observed from the E region during magnetic disturbances (the slant Es echo corresponds to the IF echo). These echoes were centered about geomagnetic north on swept azimuth soundings and were produced by scatter near the oblique reflection point in the ionosphere. Thus, we conclude that the echoes were caused by scatter from irregularities aligned along the geomagnetic field. The IF echo branches off the first order vertical incidence F region trace and increases linearly in range with frequency. It is produced by scattered energy which is least-time focused. The scatterers are essentially randomly distributed within large regions called clouds in the F region. The height of the irregularities producing the IF echo can be computed if the vertical incidence traces are clear; heights between 200 and 350 km have been found by this technique, indicating that electron density irregularities are not confined only to the lower ionosphere. From the regularity of occurrence of the IF echo, it is highly probable that the irregularities extend throughout much of the F region. The constant range echo is produced by energy scattered from the field-aligned surface of a cloud of irregularities. The soundings were made to the north so the clouds producing the observed constant range echo extended east and west. The IF and the constant range echoes are useful research tools because they indicate the amount of cloudiness present in the F region. During the summer day, the F region is relatively free of clouds, while during the winter night, it is quite overcast. The cloud size and distribution depend primarily upon the zenith angle of the sun, the smaller the zenith angle, the smaller and fewer the clouds. Geomagnetic effects do not appear to influence the behavior or the F region clouds, although this point is somewhat uncertain. The E region clouds which produced the slant Es echo were definitely correlated with geomagnetic activity but not to solar radiation, there appeared to be no connection between the causes of the E and the F region direct scatter echoes even though they were propagated by the same general mechanisms. This study raised several new problems whose explanations might contribute greatly to ionospheric research. The sweep frequency sounding technique is a good method, but the system sensitivity must be raised greatly over that of the present equipment if meaningful results are to be obtained.
    • Ice Fog: Low Temperature Air Pollution; Defined with Fairbanks, Alaska as type locality

      Benson, Carl S. (Geophysical Institute at the University of Alaska, 1965-11)
      Stable pressure systems over interior Alaska sometimes produce prolonged, extreme (below -40°C) cold spells at the surface. The meteorological conditions responsible for two such cold spells are discussed in detail in Appendix A, where it is shown that the rate of radiative cooling of the air is enhanced by suspended ice crystals which are themselves a result of the initial cooling. Radiation fogs formed during the onset of cold spells are generally of short duration because the air soon becomes desiccated. These fogs consist of supercooled water droplets until the air temperature goes below the "spontaneous freezing point” for water droplets (about -40°C); the fog then becomes an ice crystal fog, or simply "Ice Fog". During the cooling cycle water is gradually condensed out of the air until the droplets freeze. At this point there is a sharp, discontinuous decrease in the saturation vapor pressure of the air because it must be reckoned over ice rather than over water. The polluted air over Fairbanks allows droplets to begin freezing at the relatively high temperature of -35°C. Between -35 and -40°C the amount of water vapor condensed by freezing of supercooled water droplets is 3 to 5 times greater than the amount condensed by 1°C of cooling at these temperatures. This results in rapid and widespread formation of ice fog (Appendix B) which persists in the Fairbanks area as long as the cold spell lasts. The persistence of Fairbanks ice fog depends on a continual source of moisture (4.. 1 x 10^6 Kg H2O per day) from human activities within the fog. Ice fog crystals are an order of magnitude smaller than diamond dust, or cirrus cloud crystals, which in turn are an order of magnitude smaller than common snow crystals (0.01, 0.1 and 1 to 5-mm respectively). The differences in size are shown to result from differences in cooling rates over 5 orders of magnitude. Most of the ice fog crystals have settling rates which are slower than the upward velocity of air over the city center. The upward air movement is caused by convection cells driven by the 6°C "heat island" over Fairbanks. This causes a reduced precipitation rate which permits the density of ice fog in the city center to be three times greater than that in the outlying areas. The inversions which occur during cold spells over Fairbanks begin at ground level and are among the strongest and most persistent in the world. They are three times stronger than those in the inversion layer over Los Angeles. Thus, the low-lying air over Fairbanks stagnates and becomes effectively decoupled from the atmosphere above, permitting high concentrations of all pollutants. The combustion of fuel oil, gasoline, and coal provides daily inputs of: 4.1 x 10^6 kg CO2 ; 8.6 x 10^3 kg SO2 ; and 60, 46 and 20 kg of Pb, Br and Cl respectively, into a lens-like layer of air resting on the surface with a total volume less than 3 x 10^9 m^3. The air pollution over Fairbanks during cold spells couldn't be worse, because the mechanisms for cleaning the air are virtually eliminated while all activities which pollute the air are increased.
    • Incidence of Auroras and Their North-South Motions in the Northern Auroral Zone

      Davis, T. Neil; Kimball, Donald S. (Geophysical Institute at the University of Alaska, 1960-01)
      Studies of the incidence of auroral forms and their north and south motions are made by using a close-spaced array of all-sky cameras located in the northern auroral zone at the approximate geomagnetic longitude 250°E. It is found that during the observing season 1957-58 the peak of the average auroral zone occurred at 66-67° geomagnetic latitude. Although the southern extent of auroras retreats northward after local magnetic midnight, the southward motion of the individual forms, observed at the southern edge of the auroral zone, predominates over the northward motion throughout most of the night. The data indicate the existence on any given night of a latitude position near which many auroral forms occur. The first motion of auroras incident north of this position tends to be northward, and the first motion of auroras incident south of this position tends to be southward. A curve showing the occurrence of auroral forms peaks at, and is nearly symmetrical about, local geographic midnight, but the intensity of auroral emissions measured over the celestial hemisphere remains at a high level after midnight.
    • Indices of Upper Atmospheric Disturbance Phenomena in Auroral Zone

      Elvey, C. T.; Sugiura, M. (Geophysical Institute at the University of Alaska, 1958-12)
      The earlier orbits and ephemerides for the Soviet satellites were not sufficiently accurate to be very useful in making observations in Alaska. Extrapolations from our own observations gave better predictions. This merely pointed out the fact that rough observations of meridian transits at high latitudes will give better values of the inclination of the orbit than precision observations at low latitudes. Hence, it was decided to observe visually the meridian transits estimating the altitude by noting the position with respect to the stars or using crude alidade measurements. The times of the earlier observations were observed on a watch or clock and the clock correction obtained from WWV. Later the times were determined with the aid of stop watches, taking time intervals from WWV signals. This rather meager program of optical observations of the Soviet satellites was undertaken to give supplementary data for use of the radio observations, and particularly to assist in the prediction of position of the satellite so that the 61-foot radar of Stanford Research Institute could be set accurately enough to observe it (the beam width at the half-power points is about 3°). This report contains primarily the visual observations made at the Geophysical Institute by various members of the staff, and a series of observations by Olaf Halverson at Nome, Alaska. In addition there is a short discussion of the geometry of the trajectory, the illumination of a circumpolar satellite, and a note on the evaluation of Brouwer's moment factors.
    • Low Energy Cosmic Ray Events Associated With Solar Flares

      Reid, George C.; Leinbach, Harold (Geophysical Institute at the University of Alaska, 1959-09)
    • A Magneto-Ionic Theory of the Aurora

      Reid, G. C. (Geophysical Institute at the University of Alaska, 1958-12)
      A qualitative description of the development of a typical auroral display as the result of an electrical discharge in the ionosphere is presented. The prime cause of the discharge is taken as the potential difference existing between points in the interplanetary medium as a result of an interaction between charged particles of solar origin and the earth's magnetic field. The characteristics of the occasional very intense aurorae visible over large areas of the earth are discussed, as well as the normal diurnal and seasonal variation of auroral occurrence. The origin of the electric field is discussed, and a possible explanation in terms of particles trapped in the earth’s magnetic field, is presented.
    • Magnetometer and direct-current resistivity studies in Alaska

      Joesting, Henry R. (University of Alaska Mineral Industry Research Laboratory, 1941)
      During the past year and a half, the territorial Department of Mines in Alaska has conducted a modest experimental program for the purpose of determining the extent to which magnetic and resistivity methods can be used in interior Alaska in connection with prospecting, mining and geological studies. Since little information is available concerning previous work, and since conditions differ considerably from those in most other regions, it was considered advisable to make a general study of the possibilities and limitation[s] of the two methods, rather than a detailed study of any single problem.
    • The measurement of ionospheric absorption using extraterrestrial radio waves

      Little, C. G. (Geophysical Institute at the University of Alaska, 1957-01-28)
      Introduction: The discovery by Jansky in 1932 of the presence of radio waves incident upon the earth from outer space has led to several new methods of studying the earth's upper atmosphere. This report describes the manner in which these extraterrestrial radio waves may be used to measure the radio absorption characteristics of the ionosphere. It opens with a brief discussion of the theory of ionospheric absorption; this is followed by a description of the basic principles involved in this new technique. Two different types of equipment which may be used for this type of absorption measurement are then discussed. The report concludes with a brief summary of three types of ionospheric absorption phenomena which have been studied at various latitudes with such equipments.
    • Mercury in the environs of the north slope of Alaska

      Weiss, H. V.; Chew, K.; Guttman, M.; Host, A. (Naval Arctic Research Laboratory, 1974)
      The analysis of Greenland ice suggests that the flux of mercury from the continents to the atmosphere has increased in recent times, perhaps partly as a result of the many of man’s activities that effect an alteration of terrestrial surfaces. Upon the exposure of fresh crustal matter, the natural outgassing of mercury vapor from the earth’s surface could be enhanced. Accordingly, mercury was measured in a variety of environmental materials gathered from the North Slope of Alaska to provide background data prior to the anticipated increase of activity in this environment. The materials were collected during the U. S. Coast Guard WEBSEC 72-73 cruises as well as through the facilities provided by Naval Arctic Research Laboratory in the spring of 1973. The method of measurement depended upon radioactivation of mercury with neutrons and the subsequent quantification of characteristic gamma radiations after radiochemical purification. Mercury concentrations in seawater at several locations in the vicinity of 151°W, 71°N averaged 20 parts per trillion. The waters from all stations east of this location showed a significantly smaller concentration. This difference may relate to penetration o f Bering- Chukchi Sea water into the southern Beaufort Sea to 151°W. Marine sediments on the shelf and slope between 143°W and 153°W contained about 100 parts per billion mercury, except for those on the continental shelf between Barter Island and the Canning River, where the concentration was less than half this value. These results are consistent with sediment input from the respective rivers when their mercury content and mineralogy are considered. The mercury content of river waters was 18 ppt and in reasonable agreement with the average of snow samples (13 ppt). The burden of mercury in plankton was 37 ppb.
    • A Note on Harmonic Analysis of Geophysical Data with Special Reference to the Analysis of Geomagnetic Storms

      Sugiura, Masahisa (Geophysical Institute at the University of Alaska, 1960-04-18)
      Some geophysical characteristics tend to have a fixed distribution relative to the sun. An example is the distribution of air temperature on an ideal earth that is perfectly symmetrical (e.g., in its pattern of land and water) about its axis of rotation. In such a case the geophysical characteristic at any fixed station on the earth undergoes a daily variation that depends only on local time (and latitude and season). This simple pattern of daily change may be modified by intrinsic changes in the solar influences on the earth. The harmonic components of the daily variation at any station may in this case undergo phase changes, in some respects corresponding to Doppler shifts of frequency in optical or sonic phenomena. Care is then needed if the results of harmonic analysis are to be properly interpreted. Such interpretation is discussed with reference to the parts Dst and DS of the magnetic storm variations. Like caution must be observed in cases where the amplitude of a harmonic variation changes,with fixed phase.
    • NUNIVAK ISLAND SUBSISTENCE COD, RED SALMON AND GRAYLING FISHERIES – PAST AND PRESENT

      Drozda, Robert M. (U.S. Fish and Wildlife Service, Office of Subsistence Management, Fisheries Resource Monitoring Program, 2010-12)
      Nunivak Islanders (Nuniwarmiut) report Pacific cod (Gadus macrocephalus; atgiiyar) was a significant and consistent subsistence resource during the first half of the 20th century. Following an absence of at least 30 years, Pacific cod returned to Nunivak waters in the mid-1980s and were once again incorporated into the Nuniwarmiut subsistence round. This report presents an overview of traditional and contemporary Pacific cod fishing primarily collected as “traditional knowledge” from Nunivak elders, as well as from literature and archival sources. The report also summarizes the current state of the Nunivak Pacific cod fishery with results of subsistence fish surveys and documentation of fishing grounds. Secondarily, historical and contemporary use and availability of Sockeye salmon (Oncorhynchus nerka; cayag), Arctic grayling (Thymallus arcticus; culugpaugar) and other subsistence fish resources are presented. Ten Nuniwarmiut elders were interviewed and each provided detailed information on previously undocumented aspects of Pacific cod fishing at Nunivak Island, including locations, availability, methods, gear, processing and storage techniques.
    • Optical Earth Satellite Observations

      Abbott, W. N. (Geophysical Institute at the University of Alaska, 1958-02-14)
      I. INTRODUCTION The earlier orbits and ephemerides for the Soviet satellites were not sufficiently accurate to be very useful in making observations in Alaska. Extrapolations from our own observations gave better predictions. This merely pointed out the fact that rough observations of meridian transits at high latitudes will give better values of the inclination of the orbit than precision observations at low latitudes. Hence, it was decided to observe visually the meridian transits estimating the altitude by noting the position with respect to the stars or using crude alidade measurements. The times of the earlier observations were observed on a watch or clock and the clock correction obtained from WWV. Later the times were determined with the aid of stop watches, taking time intervals from WWV signals. This rather meager program of optical observations of the Soviet satellites was undertaken to give supplementary data for use of the radio observations, and particularly to assist in the prediction of position of the satellite so that the 61-foot radar of Stanford Research Institute could be set accurately enough to observe it (the beam width at the half-power points is about 3°). This report contains primarily the visual observations made at the Geophysical Institute by various members of the staff, and a series of observations by Olaf Halverson at Nome, Alaska. In addition there is a short discussion of the geometry of the trajectory, the illumination of a circumpolar satellite, and a note on the evaluation of Brouwer's moment factors.
    • An Optics Field Site for Auroral Studies

      Clark, K. C.; Romick, G. J. (Geophysical Institute at the University of Alaska, 1958-07)
      The earlier orbits and ephemerides for the Soviet satellites were not sufficiently accurate to be very useful in making observations in Alaska. Extrapolations from our own observations gave better predictions. This merely pointed out the fact that rough observations of meridian transits at high latitudes will give better values of the inclination of the orbit than precision observations at low latitudes. Hence, it was decided to observe visually the meridian transits estimating the altitude by noting the position with respect to the stars or using crude alidade measurements. The times of the earlier observations were observed on a watch or clock and the clock correction obtained from WWV. Later the times were determined with the aid of stop watches, taking time intervals from WWV signals. This rather meager program of optical observations of the Soviet satellites was undertaken to give supplementary data for use of the radio observations, and particularly to assist in the prediction of position of the satellite so that the 61-foot radar of Stanford Research Institute could be set accurately enough to observe it (the beam width at the half-power points is about 3°). This report contains primarily the visual observations made at the Geophysical Institute by various members of the staff, and a series of observations by Olaf Halverson at Nome, Alaska. In addition there is a short discussion of the geometry of the trajectory, the illumination of a circumpolar satellite, and a note on the evaluation of Brouwer's moment factors.