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College of Fisheries and Ocean Sciences (CFOS)
The College of Fisheries and Ocean Sciences educates and inspires the next generation of world-class aquatic ecosystem scientists. -
Office of the Provost
The University of Alaska Fairbanks Provost is responsible for providing overall leadership, coordination and direction to UAF research and scholarly activities and graduate studies. -
School of Natural Resources and Agricultural Sciences (SNRAS)
As the primary land-grant component of the university, SNRAS administers a variety of programs and engages in cooperative efforts with federal, state, and borough governments and agencies. -
UAF Graduate School
University of Alaska Fairbanks Graduate School -
Undergraduate Research and Scholarly Activity
At the University of Alaska Fairbanks, the Office of Undergraduate Research and Scholarly Activity (URSA) supports, develops and institutionalizes UAF's diverse and robust programs of undergraduate research and creative ...
Recent Submissions
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Sea ice strengthThis report contains the results from a study of the mechanical and structural properties of sea ice; the study commenced in 1958 and was completed in late 1965. Most of the experimental work is based upon stress-strain tests in both direct compression and direct tension. Approximately 3800 of these tests were made. Those parameters anticipated to have significant effect upon strength were measured: temperature, salinity, rate of loading, crystal size, crystallographic orientation, history of the ice and depth in the ice sheet. All of these are found to be significant except that the history factor itself tended to be determined by the other parameters. The analysis was accomplished primarily by the testing of models by linear multiple regression. The models selected yield good results with multiple correlation coefficients between 0.70 and 0.98 over a range of petrofabric types. Sea ice is shown to be complex and its description requires five classifications of petrofabric types, each of which exhibit somewhat different characteristics. The load rate proved to be a highly significant parameter in both strength and stiffness in most cases. Ice failing in tension is somewhat less sensitive to load rate than is ice in compression. The interrelated effects of salinity and temperature were studied using the brine volume concept. This study yielded positive confirmation of the brine volume concept, evidence of solid salt reinforcement, and evidence of failure plane selectivity to bypass strongly reinforced planes. These aspects pertain to both tension and compression failure modes. Depth in the ice sheet is shown to be a strength factor when related to each of three parameters; rate of loading, brine volume and solid salt reinforcement. Additional work accomplished in conjunction with construction of large offshore oil drilling platforms had provided significant information concerning oscillatory failure of sea ice in compression and strength reduction at very high load rates. The ice failure force oscillation is an ice property and is not primarily a function of the response of the structure. The amplitude of oscillation is large and at a frequency in the range of most space frame structures. The failing ice may cause forced resonant vibration in structures, and the forces are large enough to resonantly vibrate structure weighing several thousand tons.
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Access, Equity, and Safety in Rural Road Development: Historical Evidence from the Dalton Highway, 1974-2024This study investigates the historical example of the construction of the Dalton Highway—the most significant new road built in Alaska since 1971—to analyze how historical changes in access (both new infrastructures and access policies) and equity (who decides, who benefits, who is seen as a stakeholder) have impacted safety, broadly defined, in rural, isolated, tribal, and indigenous (RITI) communities throughout Northern Alaska.
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Geomagnetic influences on thermospheric winds observed in the auroral zoneA large body of observations of the wind field in the high-latitude thermosphere (140 to 350 km) is examined to characterize the winds and to determine their probably source. Theories and existing models of these winds are first reviewed. The morphologies of auroral particle precipitation, electric fields, and current systems are discussed to elucidate the effects of these factors upon the wind field. Existing models suggest that the effects of auroral electric fields and heating can be separated in a geomagnetic coordinate frame. It is shown, in this study, that the mean temporal dependence of the (geomagnetic) meridional component is similar to that predicted by tidal models except the magnitudes of the observed winds are smaller than predicted (observed peak speeds – 150 m sec⁻¹). Deviations (up to 200 m sec⁻¹) of the observed meridional winds from this mean behavior are probably caused by heating of the thermosphere by Joule dissipation in the auroral electrojets. Zonal winds are shown to be principally driven by collisions of the neutrals with ions drifting under the action of the auroral zone electric field. Zonal speeds from 200 to 400 m sec⁻¹ are typical. The observed zonal winds are correlated with the direction of the auroral electric fields as inferred from magnetometer records. The response time of the observed winds to changes in direction of the electric field (northward to southward) is found to be ≈ 1¹/₂ hours. Tidal winds are of secondary importance for the zonal component (peak speeds ≈ 150 m sec⁻¹). Electric fields and Joule dissipation in the high-latitude thermosphere are concluded to be responsible for the principal observed characteristics of auroral-zone thermospheric winds.
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Learning from the Permafrost & Infrastructure Symposium: merging science, engineering, and community-based knowledgeThe 2023 Permafrost & Infrastructure Symposium brought over 30 Arctic scientists, engineers, planners, and policymakers to Northern Alaska to see the impacts of permafrost thaw on roads and community infrastructure firsthand and to learn from those who live and work in the Arctic. For the symposium’s first half (July 28–August 1), participants gathered at the Barrow Arctic Research Center in Utqiaġvik for presentations, field trips and discussions focused on critical climate-related issues prioritized by local governments on the North Slope. They were joined in Utqiaġvik by key personnel from the North Slope Borough (NSB), regional housing authority, local utility cooperative, and the Alaska Native villages of Point Lay and Wainwright. Twenty participants flew to Deadhorse, Alaska, for the start of the second half of the symposium (August 1–5), which focused on transportation infrastructure and permafrost landscapes in Prudhoe Bay and south along the 416-mile Dalton Highway towards Fairbanks. A closing half-day session at the University of Alaska Fairbanks (UAF) Usibelli Engineering Learning and Innovation Building explored climate adaptation planning strategies with talks by the Commissioner of Alaska DOT&PF and the U.S. Department of Transportation’s Office of the Secretary. The symposium produced recommendations for the future.
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Safe Reinforcement Learning for Intersection Management in RITI Communities Under Rare Extreme EventsThe rapid advancement of artificial intelligence (AI) is reshaping the transportation sector, with applications spanning autonomous vehicles, driver injury prevention, and traffic management. Efficient traffic management, particularly through adaptive intersection control, holds significant potential for reducing congestion. This study explores the application of reinforcement learning (RL) to adaptive traffic signal control in rural, isolated, tribal, and indigenous (RITI) communities, which face unique challenges such as rare extreme weather events. Standard RL approaches struggle in these contexts due to limited exposure to these rare events. In our study, we first evaluate several mainstream RL algorithms and identified two most promising approaches. Then, we propose to use offline RL algorithms, which can train on existing datasets before interacting with the real environments. This provides a robust solution because (1) it is costly to deploy the algorithm and let the traffic network operate under suboptimal policies before the algorithm learns the optimal policy, and (2) it mimics the scenario where some events are not seen in the training dataset. We compare the performance of offline RL algorithms using different offline datasets, generated by policies of different levels of expertise, in realistic test cases. Results indicate that offline RL approaches perform better when trained on datasets from expert policies, stressing the importance of the quality of the offline datasets. These findings highlight the potential of RL-based adaptive traffic control for improving transportation efficiency, especially when tailored to the specific conditions of RITI communities.
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Polar micropulsationsType Pc 1 micropulsation activity at high latitudes: Statistical analyses were made on structured Pc 1 micropulsation data recorded at College (Alaska), Thule (Greenland), and Sodankyla and Nurmijarvi (Finland) from November 1967 through January 1970. Hourly occurrences of Pc 1 were scaled for mid-frequencies, amplitudes, and “sameness” of event as seen at two or more sites. The data give evidence for the existence of a global effect in Pc 1 activity. The effect is thought to be related to drifting trapped solar wind protons, i.e. to some form of proton ring current. The existence of a midday maximum in Pc 1 production at source latitudes is verified. The Pc 1 diurnal variations observed at other latitudes, including Thule (89°), are mainly shaped by characteristics of propagation in the ionosphere horizontal duct. An event occurring on 23 Feb 1967 propagated from the vicinity of Finland, completely over the polar cap, to Alaska, at a time when the disturbance level over the polar cap was minimal. The evidence suggests that E-region electrojets and other ionospheric irregularities are effective in scattering Pc 1 waves which are propagating polewards in the duct. The scattering mechanism explains some of the occurrence characteristics, e.g. the lack of the 2-4 Hz events within the polar cap though these events are fairly common at subauroral and middle latitudes. Main regularities of micropulsations at the geomagnetic poles: Observations of micropulsations in the range from small fractions of an Hz up to several Hz were conducted at the geomagnetic poles, Thule and Vostok, from 1964 to date. Main morphological regularities of different types of pulsations in these regions were investigated. Most typical for the geomagnetic poles in the family of continuous pulsations are types Pc 2 and Pc 3. A distinct seasonal variation was established for the intensity of Pc 3. It is suggested that Pc 2 pulsations penetrate to the polar cap from the far regions of the magnetospheric tail. The deformation in the shape of the Pi 2 pulsations in the region of the geomagnetic pole is stressed. The character of their propagation from the auroral zone where their amplitude is maximum is different towards the pole and towards middle latitudes. The connection of irregular short period magnetic disturbances of the PD* type with disturbances in the interplanetary field was investigated. It was revealed that the delay in PD occurrence is different for day and night hours. Investigation of pulsation behavior at the geomagnetic poles during the growth phase of substorms led to the discovery of precursors having periods equal to several minutes. Bursts of irregular oscillations with periods of 2 to 7 minutes either appear or are intensified approximately one hour before the substorm. It is suggested that these bursts of pulsations correspond to similar oscillations at the boundary of the magnetosphere discovered by direct measurements. Preliminary results of comparison of pulsation behavior at the geomagnetic poles and of aurora development are outlined. Micropulsations associated with polar magnetic substorms: This paper presents a comprehensive study of the irregular type of electromagnetic micropulsations which occur in association with the polar substorm. An extensive review of the literature serves to define the problem and to guide the ensuing scaling, analysis and discussion of results. The study utilizes data recorded on strip chart and magnetic tape over a period of several years from several stations in Alaska and Finland and from Thule, the Danish station near the North geomagnetic pole. The analysis includes extensive statistical studies of the incidence of Pi 1 and 2 at College in relation to magnetic bays and riometer data. Incidence is measured in terms of both spectral and amplitude characteristics. Individual events are studied in detail to determine the temporal and spatial distributions of the micropulsations in relation to the magnetic substorm and electron precipitation. Charts presenting the development of the polar micropulsation substorm are prepared from the above analysis. The results of the analysis are discussed in relation to the properties of the solar wind, velocity, particle densities, and magnetic field, and to the magnetospheric substorm.
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Ionospheric drift measurements in the auroral zoneAn investigation of the apparent horizontal ionospheric drifts in the ’90 km’ region and the E-region is presented. The investigation was made using the spaced-receiver method with a frequency of 3.321 MHz at College, Alaska. The structure and random characteristics of the ionospheric irregularities are described. A comparison between the two different levels shows noticeable differences of these properties. A comparison between the ’90 km’ drift measurements and meteor winds, also obtained at College, is presented. Individual wind and drift measurements were very difficult to compare, because of the lack of meteor events. Instead, average winds and drifts were used for the comparison. The results show that during magnetically quiet periods, the comparison is good, whereas during periods of increased magnetic activity the comparison is poor. Periodic fading events observed at College are also discussed.
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Stratigraphy, petrology, and geochemistry of the Spurr Volcanic Complex, eastern Aleutian Arc, AlaskaThe Spurr Volcanic Complex (SVC) is a calcalkaline, medium-K, sequence of andesites erupted over the last quarter of a million years by the easternmost currently active volcanic center in the Aleutian Arc. The ancestral Mt. Spurr was built mostly of andesites of uniform composition (58-60% SiO₂), although andesite production was episodically interrupted by the introduction of new batches of more mafic magma. Near the end of the Pleistocene the ancestral Mt. Spurr underwent Bezymianny-type avalanche caldera formation, resulting in the production of a volcanic debris avalanche with overlying ashflows. Immediately afterward, a large dome (the present Mt. Spurr) was emplaced in the caldera. Both the ashflows and dome are made of acid andesite more silicic than any analyzed lavas from the ancestral Mt. Spurr (60-63% SiO₂), yet contain olivine and amphibole xenocrysts derived from more mafic magma. The mafic magma (53-57% SiO₂) erupted during and after dome emplacement, forming proto-Crater Peak and Crater Peak. Hybrid pyroclastic flows and lavas were also produced. Proto-Crater Peak underwent glacial dissection prior to the formation of Crater Peak in approximately the same location. The vents for the silicic and mafic lavas are in the center and in the breach of the 5 by 6 km horseshoe shaped caldera, respectively, and are less than 4 km apart. Late Holocene eruptive activity is restricted to Crater Peak, and magmas continue to be relatively mafic and derived from deep within the crust. SVC lavas are plag ± ol + cpx ± opx + mt bearing. All post-caldera units contain small amounts of high AL₂O₃, high alkali pargasite, and Proto-Crater Peak and Crater Peak lavas contain abundant pyroxenite and anorthosite clots presumably derived from an immediately pre-existing magma chamber. Ranges of mineral chemistries within individual samples are often nearly as large as ranges of mineral chemistries throughout the SVC suite, suggesting that magma mixing is common. SVC lavas are unlike experimentally produced cotectic liquids and are thus unlikely to be related to each other by fractional crystallization. Magmatic evolution must instead be controlled in large part by crustal assimilation. Flat Y-SiO₂ and Nb-SiO₂ trends and Rb enrichment beyond that which can be reasonably modeled by fractional crystallization also suggest extensive assimilation of lower crust, bulk upper crust, or partial melts of local batholithic material. Since at least the mid-Holocene there has been no shallow, silicic magma chamber at the SVC. This increases the expectation that the low resistivity layer described by Turner and Wescott (1986) is a highly conductive layer of bedrock, such as a thick, altered tuff.
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The determination of the diurnal variation of the auroral belt by radio meansBackscatter echoes in the high frequency portion of the radio spectrum exhibit a systematic southward movement in the evening and northward in the morning. Typically, the scattering belt lies about 78°N geomagnetic latitude during the day, and moves south to 65 to 70° at night. The extent of the southward movement correlates strongly with geomagnetic activity and, to a lesser degree, local time. No significant difference was found between summer and winter diurnal variations of the scattering belt. The scattering belt has been found to include the optical auroral belt; thus, it is concluded that there is no significant difference in the diurnal variation in the position of the summer and winter auroral belts for given levels of magnetic disturbance. The scattering belt was present on the College magnetic meridian during most of the two and one-half years’ observations. This is interpreted as showing the optical auroral belt existed most of the time somewhere on the College meridian, and hence on others as well. Thus, the auroral belt during the solar activity minimum period existed as a more or less closed curve around the geomagnetic pole. When the latitudinal effects are considered versus local time, the auroral belt takes the form of an oval curve, the northernmost portion approximately on the noon meridian. The size of the oval at any time is proportional to the size of the disturbance. The scattering belts as determined from simultaneous College and Thule backscatter soundings over approximately reciprocal paths generally coincided. This result shows that simultaneous soundings in four to eight directions from the magnetic pole could be used to map the auroral belt completely around the earth at any given time.
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College oblique ionogramsThis report illustrates some of the typical backscatter echoes observed at College, Alaska. Backscatter soundings are being made in five directions—015, 105, 210, 270 and 325 degrees true bearing. The majority of the echoes seen were not groundscatter as usually defined. Many echoes from the northern directions were, in fact, direct scatter echoes from the ionosphere. Groundscatter echoes were regularly observed from the south during this past winter, but only rarely from the north. Sample forward oblique ionograms recorded over the Andöya, Norway, to College, Alaska, path are shown. Preliminary results indicate that the signals were primarily propagated via E or Es layers. Signals with delays of 3 to 10 milliseconds over the great-circle path delay were quite common on all the paths monitored at College. The sample records shown contain signals with delays of 4 to 5 milliseconds.
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The magnetotelluric coast effect near a dyke or long promontoryThe magnetic and telluric fields near a vertical, infinitely deep dyke in an otherwise homogeneous plane medium are calculated. The approximate constancy of the horizontal, surface magnetic field at low frequencies is used as a boundary condition, following Weaver (1963b). Both “polarizations” of the surface electromagnetic field are considered, according to whether the electric or magnetic fields are parallel to the strike. The polarization ellipses of the telluric field and the vertical magnetic field are computed as functions of the conductivity ratio, and dyke thickness, for various observing positions and frequencies, and the fields are compared with similar calculations based on Weaver’s simple fault model. An extension is outlined and the analytical results presented for the case where both ocean and land are underlain by a non-conducting basement. The work of Rankin (1962) is thus extended to cover both polarization orientation of the surface field.
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Environmental studies for radar operations in the auroral zoneThe relations between VHF and UHF radio aurora and geomagnetic activity, as indicated by telluric current records, have been investigated. (VHF and UHF radio aurora are considered in Parts I and II, respectively, of this report.) VHF radio aurora, observed over Barrow, Alaska by a 41 Mc/s radar at Kotzebue, Alaska, and telluric current activity at Barrow show a high correlation, particularly with respect to onsets of major activity. Slight or moderate activity usually gives some forewarning of intense activity, but some disturbances have extremely abrupt onsets of intense activity. The correlation is clearly highest for overhead and nearly overhead radio aurora and drops off for separations of 300 km and more. Incoherent scatter from ionosphere has been recorded by the BMEWS UHF radar at Clear, Alaska by use of two different techniques. A generally applicable procedure is to record radar return for a period of time in analog form on magnetic tape for subsequent processing by a digital computer. The BMEWS radar is also capable of detecting incoherent scatter by the use of “DTO” reports accumulated over a period of time. Conventional ionospheric electron density profiles showing E, F1, and F2 layers, with the highest electron densities in the F2 layer, have been obtained at times. On other occasions the peak in electron density occurs at F1 layer heights. The technique is capable of providing profiles under conditions causing “blackout” of conventional ionosonde recorders.
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Nearshore ice conditions from radar data, Point Barrow area, AlaskaFrom June, 1973 to May, 1979, the University of Alaska maintained a small radar system to monitor near shore ice motion and conditions at the Naval Arctic Research Laboratory near Point Barrow, Alaska. The purpose was to support research projects which required that information. In this report, the data acquired are compiled to describe the annual cycle of the ice year in the area. A short open water season can be defined as extending from late-July to late-September. This is followed by freezeup, which is characterized by a decreasing frequency of occurrence of drifting pack ice in the area between October and January. The winter season extends from January through May and is marked by generally stable or slow-drifting pack ice, or by the absence of pack ice offshore from the edge of the fast ice. The onset of breakup in June is characterized by the increasing occurrence of drifting pack ice again. Comparison of the ice cycle with climatologic data indicates no strong correlations with variables other than (possibly) air temperature. As expected, ice activity is greatest during freezeup and breakup, with rapid changes in the directions and velocity of ice motion. Similar movement patterns occur in winter, but the ice velocities are slower. Data of the type generated by the radar system would be useful for any area in which development of offshore installations is planned. Clearly, a knowledge of the range of possible ice motion patterns and events can provide the basis for improving the design of such installations.
