This thesis presents a study of the dynamic interaction which takes place between the magnetospheric plasma and the underlying neutral atmosphere; it is hoped thus to gain a better understanding of the effects of this interaction upon the steady state configuration of the magnetosphere. The neutral portion of the atmosphere (the neutrosphere) and the overlying ionized regions (the upper atmosphere and magnetosphere) may be regarded as two distinct dynamic domains that interact in a region of transition occurring between 100 and 150 km over the earth. The neutrosphere because of its greater mass will dominate the motion, and the magnetospheric plasma can be expected to undergo motions related to those of the upper neutrosphere and transition region. However, the geomagnetic field restricts the motion of the magnetospheric plasma to a particular class, allowing one to consider the magnetospheric motion to be constrained. Motions in the transition region of the class not permitted the magnetospheric plasma will give rise to forces against the constraint. The reaction of the constraint on the atmosphere of the transition region takes the form of a Lorentz force J x B where J is the current responsible for the well known solar quiet day daily magnetic variation (Sq). The explanation for the production of this current in the transition region has traditionally been presented in terms of a dynamo-like electromotive force generated by motions of the conducting atmosphere through the magnetic field, whence the transition region is aptly named the dynamo region. The Lorentz force represented by this current constitutes a significant term in the equation of motion for the dynamo region. Another important term arises from eddy viscous stresses immediately below the dynamo region. The equation of motion for the dynamo region must thus include such forces as well as the pressure gradient and Coriolis terms. However, our almost total ignorance of the eddy viscous stress field at the lower surface of the dynamo layer at present precludes our deducing the entire dynamo layer winds from the observed Sq magnetic variation. The kinematics of the dynamo layer are discussed and the motion or the dynamo layer is divided into a symmetric and an antisymmetric part. The term symmetric is here used to describe winds in the northern and southern hemisphere that are the mirror images of each other with respect to the equatorial plane. It is demonstrated that the symmetric component gives rise to electrostatic fields transverse to the field lines, but to no currents along the field lines, while the antisymmetric case produces the converse effects. The symmetric and antisymmetric winds are further divided into components according to the horizontal electromotive force they produce. (a) Symmetric Wind. In the case of the symmetric wind, only the portion of the wind producing the solenoidal component of the horizontal dynamo electromotive force is effective in producing ionospheric currents. It is demonstrated that only this current producing wind system acts against the constraints imposed by the geomagnetic field on magnetospheric motions. The motion of the magnetospheric plasma driven by each such wind system is discussed. The earlier treatments of the dynamo theory consider the dynamo region to be a single layer in which the wind system and the electric conductivity are assumed to be uniform in height. A new, more general derivation of the layer's dynamo action is given in which no restrictions are placed upon the vertical distributions. An effective wind is defined which permits the use of the earlier equations relating the current function, the electrostatic field, and the scalar field describing the current producing part of the effective wind. The equation relating the electrostatic field and the current function is essentially that employed by Maeda (1956), allowing his solution for the portion of the electrostatic field associated with the current producing wind to remain unaffected by the stratification of the wind system. Mathematical techniques for solving the dynamo equations for the electrostatic field are developed. These allow for a quite general conductivity distribution over the globe, only requiring that it be expressible in surface harmonics. The effect of undetected zonal currents upon the solution for the electrostatic field is discussed. It is suggested that a considerable diurnal component of electrostatic field and other components as well may be hidden from us by our inability to detect the prevailing magnetic perturbations produced by zonal currents. The electrostatic field associated with the non-current producing components of the symmetric wind is likewise hidden from us. (b) Antisymmetric Wind. The equations for the current driven by the antisymmetric component of wind are derived, and some of the effects of such currents are discussed. It is found that the conduction of current along the field lines from one hemisphere to the other is associated with an interhemispheric stress between geomagnetically conjugate points of order 3 x 10⁻⁷ newtons/meter². In addition it is found that an antisymmetric layer current density of 5 amperes/km into the polar cap region (across the 75° latitude circle) might give rise to a displacement of about 150 km in the relative position of the conjugate points defined by field lines of the magnetospheric tail. It is suggested that the dynamo action in the 100 to 150 km height plays a role in determining the manner in which the magnetosphere divides itself into the corotating region and the magnetospheric tail.

Executive Summary The purpose of this report is to document economic and demographic changes for communities of the Gulf of Alaska, Southcentral Alaska, and Southeast Alaska over the period of 1950 to 2023. Over this period several major changes were made to the way that State and Federal commercial fisheries were managed in Alaska waters. These changes -particularly the introduction of the Limited Entry program in the mid-1970s and individual fishing quotas in the mid-1990’s - limited access to fisheries. Changes to fisheries access has implications not just for the fisherman directly included or excluded, but also more broadly to their home communities through the economic spillover effects that the fishing industry creates. Watson et al., (2021) shows that the impacts of the commercial fishing industry in Alaska extends beyond the income it provides to vessel captains. Fishing activity also provides for crew member and shore-side processing jobs and spillover effects into upstream and downstream industries. It also creates broader induced economic effects as income and wages are spent on local goods and services. However, as Watson et al., (2021) shows, these effects only tend to materialize in the home communities of fishermen. In other words, economic impacts follow fishermen.

Jet contrails can be frequently observed in the subarctic setting of Fairbanks, Alaska, much like in the contiguous United States. Since March of 2000, continuous digital imagery of the sky was obtained, supported by FAA flight data and radiosonde ascents at the Fairbanks International Airport. There were a total of 2504 over-flights (March 2000-July 2002) at Fairbanks, but for a great number of these, contrail observations were not possible due to clouds and/or darkness. For 590 cases, the formation of contrails could be confirmed; their life span varied widely from a few seconds to several hours. In general, cold temperatures and high relative humidity at flight level favored the formation of contrails. These conditions are frequently found in the upper troposphere close to the tropopause. Using our substantial database, different existing algorithms were tested and, in part, improved in order to predict contrail formation and lifetime. The best results were obtained with an algorithm described by Schumann (1996) and an aircraft specific contrail factor of 0.036 g/kgK. For contrails within 4 hours of the radiosonde ascents, a combined hit rate for correctly forecasting the occurrence and non-occurrence of contrails of 92% was obtained.

Although not designed as a social program to redistribute income, the Alaska Permanent Fund Dividend (PFD) has been reducing poverty by providing equal annual payments to nearly all state residents for over 40 years. We examine direct effects of the PFD on Alaska poverty rates since 1990, using US Census and American Community Survey Public Use Microdata Sample records to adjust for under-reporting of children's PFD income in official statistics. We estimate that the PFD reduced the number of Alaskans with incomes below the US poverty threshold by 20%–40%. We measure only a small effect on income distribution: a 0.02 reduction in the Gini coefficient. The effect of the PFD has been even larger for vulnerable populations. The PFD has reduced poverty rates of rural Indigenous Alaskans from 28% to less than 22%, and has played an important role in alleviating poverty among seniors and children. Aside from the special case of 2020, up to 50% more Alaska children—15% instead of 10%—would be living in poor families without PFD income. The poverty-ameliorating effects of the PFD have lessened somewhat since 2000, as dividend amounts adjusted for inflation have been declining.

With increased globalization, man-made climate change, and urbanization the landscape – embedded within the Pyrocene as part of the Anthropocene - becomes increasingly more fragmented, with habitats transitioning and getting lost; globally relevant regions considered ‘pristine' such as Alaska are no exception. Alaska holds 60% of the U.S. National Park system’s area and is of national and international importance, considering the U.S. is one of the wealthiest nations on earth. Roads, houses, mines, wind parks, agriculture, trails, etc. are just a few of the features humans created that can be summarized as ‘impervious surfaces’. Those are physical impacts and actively affecting urban-driven landscape fragmentation. Using the remote sensing data of the National Land Cover Database (NLCD; https://www.mrlc.gov/data/nlcd-2016-land-cover-alaska ), here we attempt to create the first quantification of this physical human impact on the Alaskan landscape and its fragmentation. We quantified these impacts using the well-established landscape metrics tool ‘Fragstats’, implemented as the R package “landscapemetrics” in the desktop software and through the interface of a Linux Cloud-computing environment. This workflow allows for the first time to overcome the computational limitations of the conventional Fragstats software within a reasonably quick timeframe. Thereby, we are able to analyze a land area as large as approx. 1,517,733 km2 (state of Alaska) while maintaining a high assessment resolution of 30 meters. Based on this traditional methodology, we found that Alaska has a reported physical human impact of c. 0.067%. But when assessed, we additionally overlaid other features that were not included in the input data to highlight the overall true human impact (including governances in game management unit boundaries, park boundaries, mines, etc.). We found that using remote sensing, Alaska’s human impact is actually considerably underestimated to a meaningless estimate and that the state is more seriously fragmented and affected by humans than commonly assumed. Very few areas are truly untouched and overall it displays a high patch density with corresponding low mean patch sizes throughout the study area. Instead, the true human impact is likely close to 100% throughout Alaska for several metrics. With these newly created insights, we provide the first state-wide landscape data and inference that are likely of considerable importance for land management entities in the state of Alaska, and for the U.S. National Park systems overall, especially in the changing climate. Likewise, the methodological framework presented here shows an Open Access workflow and can be used as a reference to be reproduced virtually anywhere else on the planet to assess more realistic large-scale landscape metrics and human impacts on the landscape in an Open GIS environment for more sustainable landscape stewardship and mitigation in policy.

This 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.

A 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.

The 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.