• Rabies data for Canada and Alaska/US for GIS model predictions

      Hueffer, K.; Huettmann, F. (2020-04)
      This value-added data set is part of a publication by Huettmann and Hueffer (in prep) and includes the GIS layers for rabies and predictions of Canada, assessed with Alaska locations ((taken from Huettmann et al. 2015). This project compiled the best publically available rabies data for Canada, and models them for the Northern part of the the North American continent (Alaska and Arctic Canada). The environmental data sets are in a common GIS format (ESRI and ASCII grids) and are taken from public Open Access sources. The rabies data sets are point data, as rabies was reported by the Canadian Food Inspection Agency, and processed in the lab. The dataset is 5GB in size and consists of 20 files.
    • Rabies on the Last Frontier: A Phylogeographical Look at Red (Vulpus vulpus) and Arctic (Vulpus lagopus) Fox with Respect to Mitochondrial DNA and the Spatial Diffusion of Rabies

      Clement, Christopher J. (2012)
      Vulpus vulpus and Vulpus lagopus are terrestrial animals that live in Alaska. They are also common carriers of the rabies virus. It has been determined that there are three different clades of rabies in Alaska being vectored by these two species of fox, but it is not clear why there are no endemic rabies in the Interior. We are interested in the migration patterns of Vulpus vulpus and Vulpus lagopus, the spread and maintenance of the rabies virus as a function of climate warming. We hypothesize that there is some element, whether biological or geographical, that restricts the virus from spreading into the interior and maintaining itself as much as it does in the coastal regions of Alaska. This research provides a model for determining how the virus spreads under retreating Arctic conditions, as the globe warms.
    • Rabies Virus In Arctic Fox (Vulpes Lagopus): A Study Of Pantropic Distribution

      Gildehaus, Lori A.; Runstadler, Jonathan (2010)
      Rabies is endemic in Arctic foxes, in Alaska and other Arctic regions and cold temperatures may preserve the virus in Arctic climates in infected animal carcasses. These frozen carcasses may provide a source of infection throughout winters and thereby propagate the rabies virus within animal populations in the Arctic. It was hypothesized that rabies virus antigen is present in the soft tissues of naturally infected Arctic foxes, Vulpes lagopus. Using a direct rapid immunohistochemistry test (DRIT) and a fluorescent antibody test (FAT), thirteen organ tissues from twelve naturally infected and three experimentally infected Arctic foxes were tested. All tissues, except testes, tested positive for rabies virus antigen by the DRIT, the FAT, or both in at least one fox. Although the DRIT detected rabies virus antigen in non-neuronal tissues, it did not detect antigen in as many non-neuronal tissues as the FAT. Spleen and stomach tissues had the highest rate of rabies virus detection by the FAT and using a combination of non-neuronal tissues would be the best substitute for brain if brain were unavailable.
    • Radar studies of turbulence and lidar studies of the nickel layer in the Arctic mesosphere

      Li, Jintai; Collins, Richard L.; Simpson, William R.; Newman, David E. (2016-05)
      This thesis presents studies of the Arctic middle atmosphere using Incoherent Scatter Radar (ISR) and resonance lidar at Poker Flat Research Range (PFRR), Chatanika, Alaska. The Poker Flat Incoherent Scatter Radar (PFISR) provides measurements of mesospheric turbulence and the resonance lidar provides measurements of mesospheric nickel layer. We develop retrieval and analysis techniques to determine the characteristics of the turbulence and the nickel layer. We present measurements of mesospheric turbulence with PFISR on 23 April 2008 and 18 February 2013. We characterize mesospheric turbulence in terms of the energy dissipation rate as a function of altitude and time on these days. We present an extensive analysis of the radar measurements to show that the use of high quality PFISR data and an accurate characterization of the geophysical conditions are essential to achieve accurate turbulent measurements. We find that the retrieved values of the energy dissipation rate vary significantly based on how the data is selected. We present measurements of mesospheric nickel layer with resonance lidar on the night of 27-28 November 2012 and 20-21 December 2012. We characterize the mesospheric nickel layer in terms of the nickel concentration as a function of altitude on these days. We find that our nickel concentrations are significantly higher than expected from studies of meteors. We present an extensive analysis of the lidar measurements to show that these measurements of unexpectedly high values of the nickel concentrations are accurate and not biased by the lidar measurements.
    • Radial and azimuthal dynamics of the io plasma torus

      Copper, Matthew; Delamere, Peter; Ng, Chung-Sang; Otto, Antonius (2015-05)
      The moon Io orbits Jupiter emitting neutral particles from its volcanic surface. This emission is ionized and forms the Io plasma torus around Jupiter. The variation of conditions at Io and Jupiter lead to variations in the content of the plasma in the torus. Volcanoes on Io's surface erupt and change the rate of neutral input. Hot electrons (30-100 eV), whose abundances vary in azimuth, create highly ionized species. Radial variation in subcorotation velocities, velocities less than than that of the motion of the dipole magnetic field, creates shears while maintaining coherent radial structure in the torus. Poorly understood changes in plasma density circulate through the torus creating the anomalous System IV behavior that has a period slightly longer than the rotation of Jupiter's magnetic field. This thesis summarizes the research that has produced a two-dimensional physical chemistry model, tested several existing theories about subcorotation velocities, System IV variation, and hot electrons, and adopted new methods of Io plasma torus analysis. In an attempt to understand important dynamics, the thesis modeled differing scenarios such as an initialized two-peak structure, a subcorotation profile dictated by mass loading and ionospheric conductivity, and a critical combination of two populations of hot electrons that accurately mimics the observed System IV phenomenon. This model was also used to solve the inverse problem of determining the best fit for the model parameters, neutral source input rate and radial transport rate, using observations of density, temperature, and composition. In addition the thesis shows the need for multi-dimensional modeling and the results from its groundbreaking two-dimensional model.
    • Radiation Information from 1958 δ2

      Basler, R. P.; DeWitt, R. N.; Reid, G. C. (Geophysical Institute at the University of Alaska, 1960-01)
      The telemetered radiation information from the satellite 1958 δ2 (Sputnik III) has been analyzed for sixty-two separate passes recorded in College, Alaska. The data indicate a dependence of radiation intensity on altitude in the range 250-500 km. Both the high and low energy components apparently contribute to the overall increase of intensity with altitude, but the presence of a continuous afterglow in the scintillating crystal prevented detailed interpretation of the results.
    • Radiation transport in cloudy and aerosol loaded atmospheres

      Kylling, Arve; Stamnes, Knut; Shaw, Glenn E.; Weeks, Wilford W.; Rees, Manfred H.; Smith, Roger W. (1992)
      The equation for radiation transport in vertical inhomogeneous absorbing, scattering, and emitting atmospheres is derived from first principles. It is cast in a form amenable to solution, and solved using the discrete ordinate method. Based on the discrete ordinate solution a new computationally efficient and stable two-stream algorithm which accounts for spherical geometry is developed. The absorption and scattering properties of atmospheric molecules and particulate matter is discussed. The absorption cross sections of the principal absorbers in the atmosphere, H$\sb2$O, CO$\sb2$ and O$\sb3,$ vary erratically and rapidly with wavelength. To account for this variation, the correlated-k distribution method is employed to simplify the integration over wavelength necessary for calculation of warming/cooling rates. The radiation model, utilizing appropriate absorption and scattering cross sections, is compared with ultraviolet radiation measurements. The comparison suggests that further experiments are required. Ultraviolet (UV) and photosynthetically active radiation (PAR) is computed for high and low latitudes for clear and cloudy skies under different ozone concentrations. An ozone depletion increases UV-B radiation detrimental to life. Water clouds diminish UV-B, UV-A and PAR for low surface albedos and increase them for high albedos. The relative amount of harmful UV-B increases on overcast days. The daily radiation doses exhibit small monthly variations at low latitudes but vary by a factor of 3 at high latitudes. Photodissociation and warming/cooling rates are calculated for clear skies, aerosol loaded atmospheres, and atmospheres with cirrus and water clouds. After major volcanic explosions aerosols change O$\sb3$ and NO$\sb2$ photodissociation rates by 20%. Both aged aerosols and cirrus clouds have little effect on photodissociation rates. Water clouds increase $(\sim$100%) photodissociation rates that are sensitive to visible radiation above the cloud. Solar warming rates vary by 50% in the stratosphere due to changing surface albedo. Water clouds have a similar effect. The net effect of cirrus clouds is to warm the troposphere and the stratosphere. Only extreme volcanic aerosol loadings affect the terrestrial warming rate, causing warming below the aerosol layer and cooling above it. Aerosols give increased solar warming above the aerosol layer and cooling below it.
    • Radiation transport in the atmosphere - sea ice - ocean system

      Jin, Zhonghai; Stamnes, Knut; Lynch, Amanda; Rees, Manfred H.; Shaw, Glenn E.; Tsay, Si-Chee; Weeks, Wilford F. (1995)
      A comprehensive radiative transfer model for the coupled atmosphere-sea ice-ocean system has been developed. The theoretical work required for constructing such a coupled model is described first. This work extends the discrete ordinate method, which has been proven to be effective in studies of radiative transfer in the atmosphere, to solve the radiative transfer problem pertaining to a system consisting of two strata with different indices of refraction, such as the atmosphere-ocean system and the atmosphere-sea ice-ocean system. The relevant changes (as compared to the standard problem with constant index of refraction throughout the medium) in formulation and solution of the radiative transfer equation, including the proper application of interface and boundary conditions, are presented. This solution is then applied to the atmosphere-sea ice-ocean system to study the solar energy balance in this coupled system. The input parameters required by the model are observable physical properties (e.g., the profiles of temperature and gas concentrations in the atmosphere, and the profiles of temperature, density, and salinity in the ice). The atmosphere, sea ice and ocean are each divided into a sufficient number of layers in the vertical to adequately resolve changes in their optical properties. This model rigorously accounts for the multiple scattering and absorption by atmospheric molecules, clouds, snow and sea water, as well as inclusions in the sea ice, such as brine pockets and air bubbles. The effects of various factors on the solar energy distribution in the entire system have been studied quantitatively. These factors include the ice salinity and density variations, cloud microphysics as well as variations in melt ponds and snow cover on the ice surface. Finally, the coupled radiative transfer model is used to study the impacts of clouds, snow and ice algae on the light transport in sea ice and in the ocean, as well as to simulate spectral irradiance and extinction measurements in sea ice.
    • Radiative transfer modeling in the coupled atmosphere-ocean system and its application to the remote sensing of ocean color imagery

      Yan, Banghua; Stamnes, Knut; Nielsen, Hans; Watkins, Brenton; Olson, John (2001-08)
      Ocean color is the radiance emanating from the ocean due to scattering by chlorophyll pigments and particles of organic and inorganic origin. Thus, it contains information about chlorophyll concentrations which can be used to estimate primary productivity. Observations of ocean color from space can be used to monitor the variability in marine primary productivity, thereby permitting a quantum leap in our understanding of oceanographic processes from regional to global scales. Satellite remote sensing of ocean color requires accurate removal of the contribution by atmospheric molecules and aerosols to the radiance measured at the top of the atmosphere (TOA). This removal process is called 'atmospheric correction.' Since about 90% of the radiance received by the satellitee sensor comes from the atmosphere, accurate removal of this portion is very important. A prerequisite for accurate atmospheric correction is accurate and reliable simulation of the transport of radiation in the atmosphere-ocean system. This thesis focuses on this radiative transfer process, and investigates the impact of particles in the atmosphere (aerosols) and ocean (oceanic chlorophylls and air bubbles) on our ability to remove the atmospheric contribution from the received signal. To explore these issues, a comprehensive radiative transfer model for the coupled atmosphere-ocean system is used to simulate the radiative transfer process and provide a physically sound link between surface-based measurements of oceanic and atmospheric parameters and radiances observed by satellite-deployed ocean color sensors. This model has been upgraded to provide accurate radiances in arbitrary directions as required to analyze satellite data. The model is then applied to quantify the uncertainties associated with several commonly made assumptions invoked in atmospheric correction algorithms. Since Atmospheric aerosols consist of a mixture of absorbing and non-absorbing components that may or may not be soluble, it becomes a challenging task to model the radiative effects of these particles. It is shown that the contribution of these particles to the TOA radiance depends on the assumptions made concerning how these particles mix and grow in a humid environment. This makes atmospheric correction a very difficult undertaking. Air bubbles in the ocean created by breaking waves give rise to scattered light. Unless this contribution to the radiance leaving the ocean is correctly accounted for, it would be mistakenly attributed to chlorophyll pigments. Thus, the findings in this thesis make an important contribution to the development of an adequate radiative transfer model for the coupled atmosphere-ocean system required for development and assessment of algorithms for atmospheric correction of ocean color imagery.
    • Radio Properties of the Auroral Ionosphere

      Little, C. Gordon; Merritt, Robert P.; Rumi, G. C.; Stiltner, Ernest; Cognard, Rene (Geophysical Institute at the University of Alaska, 1958-05-31)
      This report, prepared during May 1958, summarizes the analysis of over twelve months of amplitude and angular scintillation data obtained using phase-switch interferometers at 223 Mc and 456 Mc on the Cygnus and Cassiopeia radio sources. The main parameters of the equipment used are first discussed. The method of scaling the records, involving the arbitrary division of the records into four (456 Mc) or six (223 Mc) levels of activity is then described. The probability distributions of the amplitude variations, as derived using a phase-sweep interferometer, are given for the main levels of scintillation activity at 223 Mc. Values of mean fractional deviation of power, -A.P. } for the main levels of activity at 223 Mc are also given. Preliminary probability distributions of angular deviation, and values of mean angular deviation, are also given for the different levels of activity at 223 Mc. The solar-time dependence and sidereal-time (elevation angle) dependence of the scintillation activity are presented arid c6mpared with similar data from temperate latitudes. The report concludes with a section in which a recent theory of radio star scintillations^ is modified to include the effect of an elongation of the irregularities along the earth's magnetic lines of force.
    • Radio Properties of the Auroral Ionosphere, Final Report (Phase I)

      Reid, C. G.; Stiltner, E.; Cognard, R. (Geophysical Institute at the University of Alaska, 1959-02)
      It has been found in recent years that a study of the fluctuations in the signals received from radio stars affords a powerful means of investigating the irregular structure of the ionosphere. In 1955 studies of this type, using frequencies of 223 Me and 456 Me, were initiated at the Geophysical Institute, with a view to investigating the smallscale structure of the highly disturbed auroral ionosphere. The purpose of this report is to present a complete description of the initial experimental arrangement. Further developments of the equipment and some results of analysis of the data have been presented in Quarterly Progress Reports covering the period since 1 June 1956, The report is divided into three sections. Section I contains a description of the basic philosophy of the experiment with an elementary discussion of the various parameters involved. Section II contains a brief description of the actual field installation, and Section III is devoted to the electronic design features. The diagrams pertaining to each section are located at the end of the section.
    • Radio Properties of the Auroral ionosphere, Supplement to Final Report (Phase I)

      Reid, G. C.; Stiltner, E. (Geophysical Institute at the University of Alaska, 1960-02-01)
      The usefulness of the phase-sweep technique in interferometers designed to record radio star signals is discussed. Interferometers of this type have been built for use at frequencies of 223 and 456 Mcs., and their electronic design is explained in some detail. The report also includes a discussion of the automatic data processing system which has been designed to operate in conjunction with the interferometers in the analysis of the amplitude scintillation of radio stars.
    • Radio Properties of the Auroral Ionosphere, Supplementary Progress Report

      Jalbert, Roland A.; Stiltner, Ernest; Reid, George C. (Geophysical Institute at the University of Alaska, 1958-08)
    • Radio wave propagation in the arctic

      Little, C.G. (Geophysical Institute at the University of Alaska, 1955-08-15)
      The report is divided into six main sections. The first five deal in turn with the five main Tasks specified in the contract; the sixth describes three other phases of work also concerned with radio wave propagation in the Territory. The progress in these various fields is summarized very briefly below. Task No. 1 Sweep-frequency Ionospheric Back-Scatter No progress was made on this task, owing to lack of equipment. Task No. 2 Auroral Radar Echoes An SCR-270 radar was modified for auroral radar research, and two main investigations were carried out with this equipment. The first one was to determine the mode of propagation of V.H.F. auroral echoes; the results showed conclusively that a strong aspect sensitivity exists, due to the auroral ionization being aligned along the lines of force of the earth's magnetic field. The second investigation was to determine the relationship between the radar echoes and the occurrence of visual aurora; these observations showed that the radar echoes are usually closely associated in range and azimuth with visual aurora, but that the visual brightness of the aurora is not the factor controlling the strengths of the echoes. No echoes were obtained at frequencies greater than 106 mc, owing to lack of suitable equipment. Task No. 3 Investigation of Microwave Link The experimental, observations carried out on this link showed the absence of significant tropospheric refraction effects, and the work has now been terminated. Task No. k Prediction of Auroral and Ionospheric Storms The prediction of aurora and ionospheric storms presumes a thorough understanding of the phenomena. A brief review is given of the source of the disturbances, a stream of ionized particles from the sun, and the several influences which are observed during £nd subsequent to the bombardment of the atmosphere by these particles. Research in several phases of the problem which are in progress at the Institute are mentioned as well as that which is being done on this contract. The principle effort during the past year on this contract was development of some techniques for a better understanding of the aurora. These are the all-sky camera which is being used to study the development of an auroral display and the photoelectric photometer which appears to be useful in supplying data for an index of auroral activity. Some preliminary results from both of these equipments are presented. Task No. 5 Whistlers Observations have shown the fairly frequent occurrence of whistlers at College during the early part of July 1955» Tape recordings of some of these whistlers are now being analysed to determine their frequency dispersion. Additional Work Three main phases of additional work, dealing respectively with the tropospheric propagation of V.H.F. radio waves, the diffraction and scattering of V.H.F. radio waves by mountains, and the absorption of H.F. radio waves of the ionosphere were carried out at the Geophysical Institute. Numbers one and three of these were conducted at the request of the Alaskan Command, U.S. Air Force; the second problem was investigated in view of its possible importance in point-to-point communication in the Territory.
    • Radio wave propagation in the arctic

      Little, C.G.; Dyce, R.B.; Hessler, V. P.; Leonard, R. S.; Owren, L.; Roof, R. B.; Sugiura, M.; Swenson, G. W. Jr (Geophysical Institute at the University of Alaska, 1956)
      The main body of this report is divided into eight sections, corresponding to the eight aspects of Arctic radio wave propagation listed in Section I, Purposes of the Contract, In cases where the work has already been fully described in Interim Scientific Report No. 1 (AFCRC-TN- 55-579, here in after referred to as R(l)), brief summaries only are given. The progress in these eight fields is summarized as follows: Task No. 1 Sweep-Frequency Ionospheric Backscatter Because of lack of equipment, no progress was made on this task. Task No. 2 Auroral and Meteor Echoes Three frequencies were used in this work: (a) At 50 me A low“power9 50 me radar equipments specially designed and built for auroral radar research, was operated with a steerable antenna to monitor both auroral and meteor activity,, The results showed that the diurnal distribution of meteor activity is similar at College to that observed elsewhere, and that the meteor echo rates observed on this equipment are not affected by the presence of aurora. (b) At 106 me The 106 me SCR 270 DA radar was used for two main experiments, as described in R(l). First, the aspect sensitivity of the auroral echoes was investigated. The results showed clearly that the auroral ionization giving rise to VHF auroral radar echoes is aligned along the earth's magnetic lines of force3 in that the auroral radar echoes are strongest when the radio waves are traveling perpendicularly to the magnetic lines of force through the aurora. Second, the relationship between visual and radar aurora was investigated; this work showed that the auroral radar echoes are often closely associated in range and azimuth with visual aurora, although the strength of the echoes is not proportional to the visual brightness of the auroral forms„ (c) At 210 me The 210 me SA-2 radar was installed in a trailer and tested without modification, It was then modified by the building of a steerable 16-Yagi array, by increasing the pulse length, and by reducing the receiver bandwidth„ Simultaneous operation of the 50 me and the improved 210 me equipment resulted in the detection of many auroral echoes at the lower frequency; no auroral (or meteor) echoes were obtained on the 210 me equipment during the contract period although good mountain * echoes were obtained at ranges up to 250 km„ Task No„ 3 Investigation of Microwave Link As explained in R(l), the experimental observations carried out on this link showed the absence of significant tropospheric refraction effects, and the work was terminated at the end of the first year of the contract. Task No. 4 Prediction of Auroral and Ionospheric Storms Several types of work were undertaken in order to improve our understanding of auroral and ionospheric storms; these storms are two aspects of the bombardment of the upper atmosphere by particles from the sun, In particular, a solar radio interferometer was set up to monitor the solar radio emissions at 65 me As described in R(l), an all sky camera and a photoelectric photometer were developed for the monitoring of the visual auroral activity. An investigation of earth potentials has shown that they provide a simple method of monitoring magnetic activity; some tests were also made using a rapid-response electronic magnetometer. Some of the results obtained with these equipments are discussed in the report. A study of the form of the front surface of a neutral corpuscular stream advancing into a magnetic field similar to the earth's magnetic field is presented. This study shows the presence of equatorial and polar forbidden zones and the fact that only the particles arriving near the border between these forbidden zones can reach the earth's upper atmosphere. An equatorial motion of the zone of bombardment could be produced by an increase either in particle density or in particle velocity. Task No. 5 Whistlers A new type of whistler has been discovered that has simultaneous rising and descending components. Analysis of data obtained during the contract period indicates a diurnal variation in the rate of occurrence of whistlers that appears to be correlated with ionospheric heights. A correlation between the day-to- day occurrence of the dawn chorus and the daily K-index sums is also found. Task No. 6 Diffraction and Scatter of Radio Waves by Mountains (a) Diffraction The diffraction of VHF radio waves by mountains has been investigated over three diffraction paths. The results show that the experimentally observed signal strengths are in fair agreement with the values calculated theoretically using knife-edge approximations. One important observation, which has not been reported previously, is the variability of the diffracted signal strength from point to point across the ground. Also, although diffracted signals are normally described as being very constant in amplitude, slow fades lasting some hours and occurring over a relatively narrow frequency band were observed over one 200- mile path. (b) Mountain scatter Observations of mountain scatter were made using the SCR-270 DA radar and a mobile receiving equipment. The results imply that detectable scattered signals can be obtained over a very wide range of azimuths (greater than + 135°) relative to the line joining the transmitter and the mountain. It was found that the scattered signals were considerably broadened in pulse length.Task No. 7 Ionospheric Absorption The work done in connection with ionospheric absorption under this contract has been described previously in R(l). Undertaken at the request of the 58th Weather Reconnaissance Squadron, USAF, this study demonstrated convincingly that their communication failures were caused by ionospheric absorption phenomena, rather than by equipment or personnel failures. Task No. 8 Assistance to the Alaska Air Command on Problems of Radio Propagation As described in R(l), an investigation of a VHF radio link was made at the request of the Alaska Air Command. Continuous records of received signal strength at each end of the link revealed that the communication failures were caused by tropospheric refraction effects. A low-noise preamplifier, built and operated in parallel with a normal equipment, was found to reduce the number of fade-outs. A one-day symposium on Arctic radio wave propagation was held at the Geophysical Institute on January 26, 1956, for the benefit of communications personnel in the territory,, Approximately fifty visitors attended these meetings. The Geophysical Institute has also assisted the Alaska Air Command by the loan of electronic equipment and pen recorders as well as by supplying specialists who have acted in an advisory capacity on problems of radio wave propagation.
    • Radiowave Scattering Structure In The Disturbed Auroral Ionosphere: Some Measured Properties

      Fremouw, Edward Joseph; Philip, K.; Parthasarathy, R.; Tryon, J.; Owren, L. (1966)
    • Radon Concentrations in Public Facilities in Alaska

      Leonard, Shelby J.; Hawkins, Daniel B.; Tilsworth, Timothy (1987-07)
      Radon levels were measured in forty public facilities throughout Alaska. Test buildings consisted mainly of schools, DOT/PF maintenance garages, and office buildings. The project had two general goals: 1) To determine whether areas of potentially high indoor radon levels can be identified based on knowledge of the bedrock geology in the area, and 2) to determine if there is cause for concern regarding radon levels in public facilities in Alaska. Radon levels measured ranged from 0.0 to 5.2 pCi/l with a mean value of 0.6 pCi/l. No conclusive evidence was found correlating radon concentration with the geology of an area. The data suggest no urgency regarding radon levels in public facilities in Alaska, especially where mechanical ventilation and positive building pressure influence the dispersion of concentrations. However, the small size of the sample and the fact that most of the buildings sampled were mechanically ventilated does not rule out the possibility that higher radon levels may yet be found.