• Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna

      Bryan, Anna Laura; Hundertmark, Kris; Horstmann-Dehn, Lara; Hardy, Sarah; Quakenbush, Lori (2014-08)
      Stomach contents, stable isotopes, fatty acids, and more recently fecal DNA are commonly used to infer the diet of marine mammals. However, how complementary or contradictory these methods are, especially when considering individual diet variability, remains poorly understood. This study assessed the differences in the dietary information resulting from stomach contents, stable isotopes, and fatty acids for adult bearded seals (Erignathus barbatus), and fishes identified from stomach contents and fecal DNA for bearded and ringed seals (Pusa hispida), harvested in Alaska for subsistence use. Stomach contents and fecal DNA provided information on recently consumed prey. In contrast, stable carbon and nitrogen isotopes of muscle and fatty acid profiles of blubber provided information on prey consumed and integrated over a longer time frame, but taxonomic resolution of prey was low. Overall, stomach contents provided the most dietary data, while fecal DNA delivered the least. Using denaturing gradient gel electrophoresis (DGGE) of 16S gene fragments, only 40% of the fecal samples (12 bearded and one ringed seal) produced detectable DNA suitable for reference gene amplification. Only three fish species could be positively identified in the diet of seals (Arctic cod, Boreogadus saida; shorthorn sculpin, Myoxocephalus scorpius; and an unknown snailfish species, Liparidae) when using fecal DNA. In a dietary comparison, and despite differences in dietary time frames, the relative occurrence (RO) of prey from stomach contents and the mean proportions of prey source groups from a Bayesian stable isotope mixing model (SIAR) were similar. The proportions of indicator fatty acids from full-thickness blubber, such as 16:4n-1, 20:5n-3, 20:4n-6, 20:1n-9, 22:1n-11, and the presence of non-methylene-interrupted fatty acids were similar to other fatty acid studies of bearded seals in Alaska, and suggest a benthic diet. Overall, the methods yielded different, but not necessarily contradictory results.
    • Identity crisis: how ideological and rhetorical failures cost Egyptians their revolution

      Abou Ghalioum, Ramzi; DeCaro, Peter; O'Donoghue, Brian (2019-05)
      The Egyptian uprising, which began on January 25, 2011, and ended on February 11, 2011, culminated in the ending of President Hosni Mubarak's 30-year reign as dictator. After free elections in which the Muslim Brotherhood ascended to power in the country, they were ousted in a military coup d'état only one year after their ascension to power and were replaced by former military general Abdul-Fattah el-Sisi. The symptoms which led the country to rise up against Mubarak continue to exist under el-Sisi today, indicating that no revolution really took place. This paper answers the question, "why did the revolution fail?", offering a rhetorical reason for the revolution's failure. The uprisings, which were billed as decentralized, offer unique opportunities for analysis of rhetorical strategy. This paper uses the reconstitutive-discourse model, a critical model which examines a rhetor's reconstitution of their audience's character, to examine the rhetoric of three different parties in the revolution. First, it examines the rhetoric of all protestors irrespective of source via Twitter and on the ground protestors; next it looks at the rhetoric of Wael Ghonim, who is credited with instigating the uprisings, and Mohammed ElBaradei, an influential figure who became interim vice-president in the aftermath of the uprisings. The study found that first, the uprisings were not really decentralized and indeed has leaders. Further, rhetorical failures on the part of its leaders caused the uprisings to fail in their goal of democratic revolution.
    • If I were to ask my mother

      Forshaw, Natalie C.; Brightwell, Gerri; Burleson, Derick; Heyne, Erik (2008-12)
      If I Were to Ask My Mother is a collection of personal essays that focuses on the narrator’s attempt to recreate her past through exploring childhood memories and entries of family diaries and other artifacts. In the first essay, the narrator’s childhood diaries are destroyed by her mother, an act seen by the adult narrator as an attempt by the mother to silence her daughter’s voice. The difficult mother/daughter relationship is a theme in the remaining essays as the narrator attempts to recreate the destroyed past by exploring her childhood memories. Diary entries are included in many of the essays in an attempt to compare memories with the stories found in the family diaries. Missing diary entries encourage the narrator to interpret the silences by speculating what might have been written. Sometimes, as the narrator discovers, the artifacts themselves hide the past’s truths.
    • The Igiugig Community Cultural Center: an indigenous plan in process

      Salmon, AlexAnna; Black, Jessica C.; Sekaquaptewa, Patricia S.; Stern, Charlene B.; Carothers, Courteny L. (2020-05)
      Indigenous planning practices of the Village of Igiugig have long identified the need for a community cultural center. This research project used a community-based participatory approach to explore the type of cultural center that will best serve residents and visitors alike. Through various community meetings, semi-structured interviews of key informants, and surveys of area businesses, Igiugig was able to articulate the main functionality of the center, as well as inform a design process for and by an Indigenous community in rural Alaska. One outcome of this process is a resource guide for the Igiugig Village Council, for the remainder of the planning and implementation of the community cultural center.
    • Igneous rocks and structures of the Nixon Fork Mine, Alaska, and their relations to ores

      Perttu, Brian; Newberry, Rainer; Wallace, Wesley; Layer, Paul (2013-12)
      The Nixon Fork Mine is a high-grade Cu-Au skarn deposit located near the western contact of the 5 square km Late Cretaceous Mystery pluton with marble, 7 km southeast of the Iditarod-Nixon Fork (I-NF) fault. This fault strikes at ~060�, and can be traced for ~400 km, with a minimum dextral displacement of ~90 km. Close proximity suggests that the Nixon Fork deposit should have been affected by the I-NF fault. In order to assess the structural evolution, I analyzed the orientations of geologic structures. I transcribed 1172 structures from previous mapping (to assess structures) and converted 186 maps into Vulcan CAD software (to create a three-dimensional model). I also acquired ������Ar/�_��_Ar dates for eleven representative potassium-bearing minerals and rocks. I identified six different episodes of deformation, including intrusion of felsic dikes, intrusion of mafic dikes, two episodes likely related to the I-NF fault, and two other poorly constrained episodes. ������Ar/�_��_Ar dates show the skarn is significantly younger than the Mystery Creek pluton, indicating it was likely sourced from an unexposed pluton. The main skarn pipe can be approximated as a line oriented ~210�/65�, which is approximately the intersection of planes defined by felsic dikes and major veins.
    • The illusion of knowledge: the evolution of early cartographic conceptions of Alaska

      Sherman, Neva (2006-08)
      The evolution of early cartographic conceptions of Alaska is marked by rises and falls in the advancement of knowledge, due to factors including the power of cartographers to perpetuate geographic speculation, unsuccessful expeditions of exploration, bureaucratic policies of secrecy, and purposeful deceit. This thesis examines that evolution, from the first appearance of western North America on world maps in the sixteenth century, through Russian expeditions to the region, to Captain James Cook's accurate mapping of the extent of Alaska in the eighteenth century, analyzing the factors that influenced Alaska's cartographic depictions and the real-life implications of those depictions. The maps that preceded Cook's are highlighted, placing Cook's cartographic contributions in context.
    • Imaging And Imaginings Of Hawaiianness In The Contemporary Hawaiian Islands

      Meredith, Ashley; Koester, David; Managan, Jane Kathryn (2010)
      The desire for the Hawaiian Kingdom to be restored and recognized as a nation-state has been a common interest among Hawaiians since the illegal United States occupation in 1893. However, colonial induced turbulence, caused by annexation, statehood, an early 20th century ban on Hawaiian language and cultural activities, the 50 percent blood quantum rule, and tourism, have had a profound impact on perceptions of Hawaiianness and Hawaiian identity and unity. With this historical backdrop, the thesis presents an analysis of the role and impact of the visual landscape in the construction and maintenance of individual and group identity in Hawai`i. The ethnographic fieldwork for this study, in addition to general observations, involved three programmatic research activities: participant photographic observations, a pile sort, and category tests. These exercises used images that reflected various aspects of Hawaiian history, symbolism and iconography. The aim of these open-ended but controlled activities was to gain a deeper understanding of contemporary Hawaiian identity through indigenous Hawaiians' and Hawai`i residents' perceptions of Hawaiianness. Perceptions and expression of Hawaiianness and Hawaiian identity were examined on the basis of responses to visual elements of the public environment such as street signs, advertisements, activities, and landscapes on Hawai`i Island. Such visual elements in the public environment are often designed to meet visitors' and residents' desires and expectations. With the Hawaiian Sovereignty Movement as an important driving force, many Hawaiians are working towards "socio-visual sustainability" and a culturally sustaining and more unified future.
    • Imagining Alaska

      Zbailey, Suzanne (2000-05)
      'I'd never felt part of something big before, ' says the character of Helen near the end of 'Imagining Alaska.' Each of the protagonists in this collection of three stories and a novella strives to become part of something they imagine is greater than themselves. For example, in 'Naked, ' Veronica's desire to be taken seriously as an artist leads her to an affair with a painter, while the lawyer in 'Sweet Country Song' projects her wish for a change in her life onto a cowboy. Meanwhile, Agnes in 'St. Agnes of the Mermaids' struggles with her religious beliefs, and Helen in the title novella tries to forge a life for herself as a young widow in Alaska. The pieces are told from either the first-person or limited third-person point-of-view, so that the reader progresses through the same act of discovery the protagonist does, until both reach a final moment of revelation
    • Imagining Ityoppia: Ethiopian diaspora and Rastafarianism

      Antohin, Esther Sellassie (2005-08)
      On a very general level, this thesis explores why Ethiopians and Rastafarians - who share Ityoppi, as a general point of reference - have historically been at odds. More specifically, however, I am interested in whether the rather recent emergence of Ethiopian communities in the United States - which share experiences of diaspora and processes of "imagining from afar" with Rastafarians - has resulted in a change of Ethiopian Americans' attitude toward adherents to Rastafarianism. The main aim of this study is to give an accurate account of the Ethiopian perspective of Rastafari, which has not been articulated till the present time. To this end I first give a broad description of their arrival in the United States, and their particular diasporic experiences, which encompasses only thirty years. Finally, I explore the prevailing attitudes and perceptions of Ethiopians in the United States with respect to the Rastafarian movement. This study utilizes primary source such as interviews and surveys conducted with first and second generation Ethiopians. It employs data collected via virtual communities along with other resources on the Internet and printed publications.
    • An impact assessment of current rural Alaska village solid waste management systems: a case study

      Wilkins, William H. III; Zhang, Mingchu; Greenberg, Joshua; Mouton, Michele (2016-08)
      The purpose of this study is to examine the impacts of current and alternative solid waste management practices of two rural Alaskan villages. The EASETECH life-cycle assessment modeling tool was used to compare the current solid waste management systems for the remote villages of Kalskag and Fort Yukon across eight alternative scenarios. Annual waste generation and composition data for these two villages and data specific to processes and functions for each waste system were collected and used to modify templates within the EASETECH program to provide a life-cycle assessment for current and proposed waste management practices. The results indicate that integrated waste management practices for these remote villages may not be economically feasible or environmentally favorable. Waste management options, though limited for these remote villages, may benefit from minor system changes. These changes include transport services and burn practices that only slightly increase operating costs, but significantly reduce local social and environmental impacts. Local, accurate, and complete waste stream data could help support future management planning for the solid waste management systems of these rural villages.
    • The impact of a fluctuating freezing front on ice formation in freezing soil

      Dillon, Matthew Ryan (2012-12)
      Frost heave is typically associated with the formation of segregation ice in fine-grained soil. Coarse-grained soil is generally considered to be non-frost susceptible. Field observa-tions and laboratory experiments show that coarse-grained soil can be extremely ice-rich in specific conditions. Previous studies have shown that oscillation of the frozen-unfrozen boundary can lead to the formation of ice by a mechanism different from the segregation ice mechanism. Conditions related to the formation of ice in coarse-grained soil were in-vestigated using modern laboratory techniques. Fourteen tests were conducted on five soil types. The thickness of soil subjected to freeze-thaw cycles was varied and controlled by the magnitude and duration of applied soil temperatures. The thickness of the ice formed increased when the sample drainage was limited or prevented during cooling. Under spe-cific conditions, the formation of a discrete ice layer was observed in coarse-grained soils. Seven samples were scanned with the pCT scanner at the completion of the warming and cooling tests. The sub-samples scanned were analyzed in 2D cross-sections, and charac-terized as 3D reconstructions. Frost heave induced by the formation of ice was observed in both fine- and coarse-grained soils, including soils that were found to be traditionally non-frost susceptible.
    • Impact Of Freeze -Thaw On Liquefaction Potential And Dynamic Properties Of Mabel Creek Silt

      Zhang, Yu (2009)
      In the early winter of 2002 (November), the Alaska Denali earthquake (Mw=-7.9) caused significant damage in partially frozen fine-grained soil and extensive liquefaction was observed in glacial fine-grained saturated soil surface deposits near Tok, Alaska. It illustrated that there was a need to evaluate the seismic response and liquefaction potential of fine-grain soil in cold regions; however, until now most of the research on the liquefaction phenomenon and seismic response were mainly about soil in non-cold regions. The seismic response and liquefaction potential of soils in cold regions, especially those of fine-grained nature, has not been studied thoroughly and therefore is not well-understood. This document presents a laboratory study on liquefaction potential and cyclic response of fine-grained soil in cold regions. As the main features of the soil in the ground of cold regions, temperature change at below freezing temperatures or near-freezing temperatures, and the seasonal climate change were evaluated on liquefaction potential, dynamic properties, and post-cyclic-loading settlement of fine-grained soils. Increasing temperatures from near freezing to the completely thawed temperature (i.e., 24�C, 5�C, 1�C, and 0.5�C) were used to thaw the frozen Mabel Creek silt to simulate temperature change on it, or the Mabel Creek silt experienced several freezing and thawing alternating processes (i.e., 1, 2, and 4 freeze-thaw cycles) to simulate seasonal climate change. Triaxial strain-controlled cyclic tests were conducted to evaluate liquefaction potential, dynamic properties, and post-cyclic-loading settlement. Based on this limited laboratory effort, results show that in most cases, temperature rise and freeze-thaw cycles can impact: (a) liquefaction potential, (b) dynamic properties and (c) post-cyclic-loading settlement of fine-grained soils. However, there was one case exception and this is decribed in the following sentence. When a fine-grained soil was conditioned in a partially frozen state, the possibility and threat of liquefaction significantly increased.
    • The impact of HLA-DM on peptide binding to MHC class II

      Templeton, Megan; Ferrante, Andrea; Kuhn, Thomas; Hueffer, Karsten (2016-05)
      Recognition of peptides bound to class II major histocompatibility complex (MHCII) molecules by T cell receptors of CD4+ T cells initiates an adaptive immune response. Analysis of the antigen presentation pathway indicates that elements of the epitope selection process are critical to generation of the peptide repertoire presented to T cells. Antigen presentation by dedicated cells (APCs) involves the intracellular fragmentation of protein antigens by cathepsins, binding of the derived peptide epitopes to MHCII with the participation of the peptide-editing molecule HLA-DM (DM), and subsequent transport to the surface for recognition. This thesis focuses on the energetics and structural flexibility of the peptide-MHCII complex, and their correlation with DM-susceptibility, to identify the criteria associated with the selection of peptides by APCs for subsequent presentation to T cells. Using the human MHCII HLA-DR (DR), and peptides derived from influenza H3 HA305-318 as test system, it was observed that, in the absence of DM, stable peptide binding is not reached through independent contributions of single-point interactions, but is a distributive process that involves the peptide-DR groove dyad in its entirety highlighting the inherent flexibility of the binding process. Here, DM mechanism is investigated in its ability to impact structural flexibility of the complex. Analysis of release from and binding to DR of a gamut of HA-derived peptides at two different levels of pH reveals that structural stability is reduced as a consequence of DM function. The results indicate that the outcome of DM activity is favoring the endurance of complexes with limited structural flexibility.
    • Impact of specific CSR activities, executive & board diversity on equity valuations

      Williams, David J.; Little, Joseph; Baek, Jungho; Greenberg, Joshua (2018-05)
      The objective of this study is to identify the impact of specific corporate social responsibility behaviors on equity prices. This study uses fixed effect parametric and nonparametric regressions to quantify the effect of specific corporate social responsibility activities on the equity price multiples of a number of US firms from 1999 to 2009. The results of these empirical models consistently show that CEO diversity, corporate charitable giving, and work-life balance benefit plans, are associated with lower equity price multiples compared against similar firms that lack these characteristics. Additionally, board diversity and support of the LBGTQ community is associated with a positive impact on equity price multiples. This study provides evidence that individual corporate social responsibility activities can have drastic impacts on equity prices, leading the way for future research testing whether the magnitudes of these impacts are rational and in-line with their expected impact on financial performance and risk, or a deviation from the efficient market hypothesis.
    • The impact of teacher achievement emotions on the co-production of education services

      Kelly, Kimberly A.; Lardon, Cécile; Arthur, Melanie; Porter, David; Burleson, Derick (2013-08)
      Educational policy in the United States has evolved into a more intense system of accountability, resulting in an intensification of achievement emotions experienced by teachers. Two theoretical paradigms were used to analyze whether such emotions impact teacher effectiveness in the classroom: the control-value theory of achievement emotions and the theory of co-production. Path analysis was used to test the hypothesized model of teacher effectiveness. Two of the four hypothesized factors contributing to teacher achievement emotions, perceived level of control over instruction and perceived levels of student achievement, were found to be significant. The remaining two variables, attribution of responsibility for student achievement and the correlation between teachers' values and educational reforms, were non-significant. The post-hoc model removed these two non-significant factors and added additional paths from the variable teachers' perceived control to teacher's coping response and teacher effectiveness. The post-hoc model fit the data well as demonstrated by significant path.and goodness of fit scores. The path model was transferable across the study's demographic subgroups with the exception of experience level. Modifications were made to the post-hoc model for this subgroup by addressing paths to the coping response variable, and such changes resulted in a significant fit to the data for this subgroup. The results of this study underscore the need for teachers to feel in control of their teaching in order to implement effective teaching strategies. Therefore, educational policies that diminish or remove such control may impact teacher effectiveness Under No Child Left Behind legislation, schools labeled as failing progressively remove more and more control from the teacher. The findings of this study indicate that such practices may be counterproductive and instead may be contributing to the problem of undesired student achievement levels. Enhancing teachers' feelings of self-efficacy in the classroom is recommended for enhancing student achievement, as is looking at the issue through the lens of co-production. Co-production of education services posits that education is co-produced by the teacher and the student. Effective reforms in education, therefore, must address both sides of the teacher-student nexus.
    • Impacts of a top predator (Esox lucius) on salmonids in Southcentral Alaska: genetics, connectivity, and vulnerability

      Jalbert, Chase S.; Falke, Jeffrey; Westley, Peter; López, J. Andrés; Dunker, Kristine (2018-12)
      Worldwide invasion and range expansion of northern pike (pike; Esox lucius) have been linked to the decline of native fishes and new techniques are needed to assess the effects of invasion over broad geographic scales. In Alaska, pike are native north and west of the Alaska Mountain Range but were introduced into Southcentral Alaska in the 1950s and again in the 1970s. To investigate the history of the invasion into Southcentral Alaska, I identified 7,889 single nucleotide polymorphisms (SNPs) from three native and seven introduced populations in Alaska and examined genetic diversity, structure, and affinities of native and invasive pike. Pike exhibited low genetic variability in native populations (mean heterozygosity = 0.0360 and mean π = 0.000241) and further reductions in introduced populations (mean heterozygosity = 0.0227 and mean π = 0.000131), which suggests a bottleneck following introduction. Population differentiation was high among some populations (global FST = 0.424; max FST = 0.668) when compared to other freshwater fishes. I identified five genetically distinct clusters of populations, consisting of three native groups, a single Susitna River basin invasive group, and a Kenai Peninsula group, with little evidence of admixture among groups. The extremely reduced genetic diversity observed in invasive northern pike populations does not appear to affect their invasion success as the species range Southcentral Alaska continues to expand. To assess the vulnerability of five species of Pacific salmon (Oncorhynchus spp.) to the invasion, I combined intrinsic potential habitat modeling, connectivity estimates, and Bayesian networks across 22,875km of stream reaches in the Matanuska-Susitna basin, Alaska, USA. Pink salmon were the most vulnerable species, with 15.2% (2,458 km) of their range identified as "highly" vulnerable. They were followed closely by chum salmon (14.8%) and coho salmon (14.7%). Finally, analysis of the intersection of vulnerable salmon habitats revealed 1,001 km of streams that were highly vulnerable for all five Pacific salmon. This framework is easy to implement, adaptable to any species or region, and cost effective. With increasing threats of species introductions, fishery managers need new tools like those described here to efficiently identify critical areas shared by multiple species, where management actions can have the greatest impact.
    • Impacts of sea otter predation on commercially important sea cucumbers (Parastichopus californicus) in Southeast Alaska

      Larson, Sean D.; Eckert, Ginny L.; Woodby, Douglas A.; Kruse, Gordon H. (2012-12)
      Consequences from management actions, particularly those regarding species reintroductions, are not always immediately apparent. After sea otters were extirpated from Southeast Alaska in the 18th and 19th century fur trade, it is presumed that marine invertebrate stocks grew in the absence of sea otter predation. Since reintroduction in the 1960s, the Southeast Alaska sea otter population has grown, with great potential to deplete the commercially important sea cucumber, Parastichopus californicus. This study evaluates the interaction with and impacts of sea otters on sea cucumbers using foraging observations and sea cucumber density data collected for fishery management. Sea otter diets, in terms of edible biomass, include about only 5% cucumbers, and yet sea otters are depleting sea cucumbers; declines in sea cucumber density at sea otter affected transects ranged from 26 to 100%. Sea otter predation should be included in sea cucumber fishery management, possibly as an additional form of mortality in the surplus production model, as a step toward ecosystem based management.
    • Impacts of storm on sea ice: from case study to climate scale analysis

      Peng, Liran; Zhang, Xiangdong; Collins, Richard; Fochesatto, Javier; Polyakov, Igor (2019-12)
      Recent studies have shown that intense and long-lasting storms potentially facilitate sea ice melting. Under the background of extratropical storm tracks poleward shift, significant reductions of Arctic sea ice coverage, and thinning of sea ice thickness over the last several decades, a better understanding on how storms impact sea ice mass balance is obviously of great importance to better predict future sea ice and the Arctic climate changes. This thesis presents a multi-scale study on how storms impact sea ice, consisting of three different parts of the effort. In the first part, we examined the impacts of the 2016 summer intense storm on sea ice changes over the Chukchi Sea using ship-borne observations. The results show that the intense storm can accelerate ice melt through enhanced upper-ocean mixing and upward heat transport. The satellite-observed long-term sea ice variations potentially can be impacted by many factors. In the second part, we first explore key physical processes controlling sea ice changes under no-storm condition. We examined and compared results from 25 sensitivity experiments using the NCAR's Community Earth System Model (CESM). We found that sea ice volume, velocity, and thickness are highly sensitive to perturbed air-ice momentum flux and sea ice strength. Increased sea ice strength or decreased air-ice momentum flux causes counter-clockwise rotation of the transpolar drift, resulting in an increase in sea ice export through Fram Strait and therefore reduction of the pan-Arctic sea ice thickness. Following four tracers released over the Arctic, we found the sea ice thickness distributions following those tracers are broader over the western Arctic and becomes narrower over the eastern Arctic. Additionally, thermodynamic processes are more dominant controlling sea ice thickness variations, especially over periphery seas. Over the eastern Arctic, dynamic processes play a more important role in controlling sea ice thickness variation. Previous studies show that thin ice responds to external perturbations much faster than the thick ice. Therefore, the impacts of storms on sea ice are expected to be different compared with the western/eastern Arctic and the entral/periphery seas. In the third part, we conduct a new composite analysis to investigate the storm impact on sea ice over seven regions for all storms spanning from 1979 to 2018. We focused on sea ice and storm changes over seven regions and found storms tend to have different short-term (two days before and after storm passage), mid-term (one-two weeks after storm passage), and long-term (from 1979 to 2018) impact on sea ice area over those regions. Over periphery seas (Chukchi, East Siberian, Laptev, Kara, and Barents Seas), storms lead to a short-term sea ice area decrease below the climatology, and a mid-term sea ice increase above the climatology. This behavior causes sea ice area to have a small correlation with the storm counts from 1979 to 2018, which suggest that storms have a limited long-term impact on sea ice area over periphery seas. Both the short term and mid-term storm impacts on sea ice area are confined within a 400 km radius circle with maximum impacts shown within a 200 km radius circle. Storms over the western Arctic (Chukchi, East Siberian, and Laptev Seas) have a stronger short-term and mid-term impact on sea ice area compared with the Eastern Arctic (Barents and Kara Seas). Storms over both Atlantic and Pacific entrance regions have a small impact on sea ice area, and storms over the Norwegian, Iceland, and Greenland Seas have the smallest impact on the sea ice area. Compared to the periphery seas, storms tend to have a stronger long-term impact on sea ice area over the central Arctic. The correlation coefficients between the storm count and sea ice area exceed 0.75.
    • The implementation and evaluation of a black carbon aerosol sampler used on an unmanned aircraft during the prescribed fire experiment RxCADRE

      Craft, Tara L.; Cahill, Caherine; Douglas, Thomas; Simpson, William (2014-12)
      Black carbon (BC) aerosols impact the earth's climate by absorbing solar radiation in the atmosphere and depositing on ice surfaces and lowering the albedo of those surfaces. Black carbon aerosols have been widely studied; however, using small unmanned aircraft systems (UAS) for the airborne study of the vertical and horizontal concentrations of BC is an emerging field. Using UAS to study BC poses some challenges due to size and weight restrictions of the aircraft, as well as issues that arise when adapting ground based instrumentation for use on different aircraft. University of Alaska Fairbanks researchers successfully integrated and flew a microAeth AE-51 on a Boeing ScanEagle to measure the concentration of BC and other absorbing and scattering particles in the smoke plume from a prescribed fire experiment, RxCADRE, conducted at Eglin AFB, FL, during October and November 2012. The ScanEaglemounted microAeth successfully collected black carbon aerosols in the smoke plume. The optical particle sizing and mass loadings from an optical particle counter disagreed with the results from the microAeth, which measures absorbing aerosols. The microAeth was tested in the laboratory-using two optical particle sizers to verify the sizes and concentrations of laboratory-generated aerosols entering the instrument and determine the capabilities and limits of the instrument. The optical particle counters were used in other applications as well showing the versatility of the instruments in extreme conditions.