• An Analysis Of Using Semi-Permeable Membrane Devices To Assess Persistent Organic Pollutants In Ambient Air Of Alaska

      Wu, Ted Hsin-Yeh; Cahill, Catherine (2006)
      A region of concern for persistent organic pollutants (POPS) contamination is the Arctic, because of POPs' ability to migrate long distances through the atmosphere toward cold regions, condense out of the atmosphere in those region, deposit in sensitive arctic ecosystems and bioaccumulate in Arctic species. Thus, monitoring of POP concentrations in the Arctic is necessary. However, traditional active air monitoring techniques for POPs may not be feasible in the Arctic, because of logistics and cost. While these issues may be overcome using passive air sampling devices, questions arise about the interpretation of the contaminant concentrations detected using the passive air samplers. In this dissertation semi-permeable membrane devices (SPMDs) containing triolein were characterized and evaluated for use in sampling the ambient air of Alaska for three classes of POPS (organochlorines [OCs], polychlorinated biphenyls [PCBs] and polyaromatic hydrocarbons [PAHs]). In addition, a SPMD-based sampling campaign for POPS was conducted simultaneously at five sites in Alaska during a one-year period. The POP concentrations obtained from the SPMDs were examined to determine the spatial and seasonal variability at the locations. POP concentrations detected in SPMDs were influenced by exposure to sunlight, concentrations of particulate-bound contaminants and changes in temperature. PAH concentrations in a SPMD mounted in a sunlight-blocking deployment unit were higher than in a SPMD exposed to sunlight (P = 0.007). PCB concentrations in SPMD exposed to filtered and non-filtered air were significantly different (P < 0.0001). Derived PAH air concentrations measured using SPMD were within a factor of approximately 7 of those obtained from an air sampler in Barrow, Alaska. The field study showed three distinct groups of samples. Barrow was separated from the sub-Arctic samples and a Homer sample (September-December) was distinct from the sub-Arctic samples. The separations suggest different air masses are being sampled by SPMDs. Lower concentrations of total POPs were measured at the coastal sites than the Interior sites.
    • Anaerobic Biodegradation Of Benzene Under Environmental Conditions Of Sub -Arctic Groundwaters

      Raad, Nada Itani; Kane, Douglas (2001)
      This research was conducted to detect and understand the potential for anaerobic degradation of benzene in a sub-arctic aquifer environment. The major hypothesis tested in this dissertation is that indigenous microorganisms from anaerobic groundwater wells contaminated with BTEX (benzene, toluene, ethylbenzene, xylenes) can use benzene as a carbon or energy source under conditions favoring iron- and sulfate-reduction and methanogenesis. To test this hypothesis microcosms were prepared and incubated under anaerobic conditions, with either hematite (Fe2O3) or sodium sulfate (Na2SO4) added to permit growth of iron and sulfate reducing bacteria. Several concentrations of benzene were used as a substrate, and the microcosms were incubated at temperatures of 21�C and 4�C. Cell counts were done and some characteristics of the bacteria, such as shape, gram staining, and spore formation were determined. The aromatic hydrocarbon benzene, was anaerobically transformed under both psychrophilic (4�C) and mesophilic (21�C) conditions. The temperature and substrate concentration played a role in determining the rate at which benzene was biodegraded under conditions favorable to iron-reducing, sulfate-reducing, or methanogenic bacteria. The rate of degradation under conditions favoring methanogenesis was faster than that under iron and sulfate-reducing conditions at 4�C, but not at 21�C. In general, at 21�C the biodegradation of benzene was faster in the presence of an exogenous electron acceptor. Benzene degraded completely under iron and sulfate-reducing conditions but did not degrade completely in most of the microcosms under methanogenic conditions. Phenol and was detected as intermediates for this transformation under all conditions. Benzene degradation rates were independent of the electron acceptor. This suggests that removal of benzene was initiated via fermentation reactions occurring under all conditions. Addition of a small concentration of sulfate or ferric as electron acceptors made degradation more complete. The in vitro research conducted on the anaerobic biodegradation of benzene provided new insight into the anaerobic degradation processes that occur at cold temperatures associated with sub-arctic environments. It also provided insights of the roles different types of microorganisms may play in the natural attenuation of contaminants.
    • Biological impacts and recovery from marine disposal of metal mining waste

      Kline, Edward R. (1998)
      Waste from coastal, metal mining operations may be disposed of in the ocean. Studies were conducted using tailings and wastewater (effluent) from a proposed gold mine that is located near Juneau, Alaska, USA. The ability of invertebrates to colonize tailings after obliteration by submarine tailings disposal (STD) was assessed through a field experiment. Trays of tailings and reference sediment were placed on the sea floor and retrieved over a 22 month period. The taxonomic composition, abundance, and biomass of invertebrates that colonized tailings and reference sediment were similar. Therefore, recolonization of invertebrates after obliteration by STD should not be inhibited by the presence of these tailings as a bottom substrate. In a laboratory study, the toxicity of effluent from the milling process was compared for early life stage fish and crustaceans. Common reference species and species that are indigenous to southern Alaska were exposed to effluent. The relationship between effluent concentration and organism response was established for immobilization, paralysis, and death. For each response, the sensitivity of the reference species bracketed that of the indigenous species. An overall ranking of species sensitivity could not be made because it depended on the response that was compared. The source of effluent toxicity was determined for one of the reference species, a crustacean. A simulated effluent was created to duplicate the ionic composition of the actual effluent. Toxicity was compared in effluent, effluent with increased salinity, simulated effluent, and solutions with adjusted concentrations of ions. Calcium was in excess in the effluent, relative to seawater, and was isolated as the source of toxicity. Sodium deficiency in the effluent, relative to seawater, reduced calcium toxicity.
    • Cloud Detection And Trace Gas Retrieval From The Next Generation Satellite Remote Sensing Instruments

      Larsen, North Fredrick; Stamnes, Knut (2005)
      The objective of this thesis is to develop a cloud detection algorithm suitable for the National Polar Orbiting Environmental Satellite System (NPOESS) Visible Infrared Imaging Radiometer Suite (VIIRS) and methods for atmospheric trace gas retrieval for future satellite remote sensing instruments. The development of this VIIRS cloud mask required a flowdown process of different sensor models in which a variety of sensor effects were simulated and evaluated. This included cloud simulations and cloud test development to investigate possible sensor effects, and a comprehensive flowdown analysis of the algorithm was conducted. In addition, a technique for total column water vapor retrieval using shadows was developed with the goal of enhancing water vapor retrievals under hazy atmospheric conditions. This is a new technique that relies on radiance differences between clear and shadowed surfaces, combined with ratios between water vapor absorbing and window regions. A novel method for retrieving methane amounts over water bodies, including lakes, rivers, and oceans, under conditions of sun glint has also been developed. The theoretical basis for the water vapor as well as the methane retrieval techniques is derived and simulated using a radiative transfer model.
    • Constructed Wetlands For Wastewater Treatment In The Subarctic

      Maddux, David Charles; Sparrow, Stephen D. (2002)
      This research had two basic objectives: to assess the capability of macrophytes indigenous to the subarctic in removal of heavy metals from wastewater and to determine the feasibility of using constructed wetlands for sewage wastewater treatment in a subarctic environment with a focus on rural application. The research consisted of two parts: a greenhouse study in which indigenous macrophytes were subjected to heavy metal pollutants similar to those found in roadway runoff and a constructed wetland built to treat sewage wastewater. Five species of plants were tested in both projects: Arctophila fulva, Carex rhynchophysa, Menyanthes trifoliate, Scirpus validus and Typha latifolia . In the greenhouse study, the plants were exposed to four heavy metals: cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) over a 68-day period. The plants were grown under a photoperiod of 20 hours light:4 hours dark. There were significant differences in metal uptake among species and more metals were stored in below-ground plant parts than in above-ground plant parts. In separate experiments, plants took up zinc in greater quantities than the other metals except A. fulva which took up copper in the greatest quantity. Effects of phytotoxicity from the metal concentrations were apparent only in M. trifoliata. The constructed wetland study consisted of a five-cell system. Biological oxygen demand (BOD), total suspended solids (TSS), fecal coliforms (FC), total phosphorus (TP), total Kjeldahl nitrogen (TKN) and ammonium nitrogen (NH4+) were measured bi-weekly during each growing season over a three-year period. Reduction efficiencies, averaged over the ice-free season, ranged from 24--67% for BOD; 38--62% for TSS; 93--99% for FC; 21--60% for TP; 43--76% for TKN; and 50--92% for NH4+. The reduction of pollutants indicated the ability of constructed wetlands to work well in the subarctic. Vegetation colonized the constructed wetland rapidly, with a complex community structure emerging over the study period. Pollutant reduction appeared to be limited by the size of the constructed wetland and not by the extreme climatic conditions.
    • Continuity And Change In The Wiseman Area Of Alaska: A Look At Land And Renewable Resource Use Over Time

      Scott, Carol Patricia (1993)
      Land and renewable resource use by residents of the Wiseman area in the central Brooks Range of Alaska was investigated in 1991-1993. The study documents current and historic land and renewable resource use patterns of local residents, records resident and agency management concerns regarding these uses, and analyzes opportunities and constraints that exist for rural Alaskan communities in utilizing renewable resources. The research was accomplished through resident interviews, participant observation of community activities, and review of other community studies. Conclusions include: (1) the Wiseman community exhibits characteristics of a mixed subsistence/cash economy; (2) residents rely on resources harvested in the various local federal, state, and private land management units; and (3) the establishment of the nearby National Park, and the construction of the Dalton Highway, have significantly affected local resource use. The study also demonstrates how community involvement in research effectively allows comprehensive documentation of land and resource use. <p>
    • Distance Activism And The Arctic National Wildlife Refuge

      Raymond-Yakoubian, Julie M.; Gladden, James (2002)
      The growing phenomenon of distance place attachment and distance activism can be seen in the extensive network of non-visitors involved in the protection of places like the Arctic National Wildlife Refuge in Alaska. This type of activism is not an anomaly, but rather an increasingly significant global phenomenon, which has gone largely unexamined by researchers of environmentalism, activism, wilderness, and place attachment. Distance activism encompasses the standard definition of activism, with the addition that distance activists must not have had physical contact with the natural environment for which they are being active. I argue that distance activists' actions and beliefs can be understood, in part, in terms of the conceptual frameworks of geopiety, topophilia, and place attachment. Furthermore, I argue that distance activism deserves a proper place in place attachment theorizing. Distance activism on behalf of the Arctic Refuge is examined as a case study of this important phenomenon. <p>
    • Distant vistas: Bradford Washburn, expeditionary science and landscape, 1930-1960

      Sfraga, Michael P.; Pearson, Roger (1997)
      Bradford Washburn is primarily known for his Alaskan mountaineering accomplishments and mountain photography. Between 1930 and 1960, Washburn led 19 expeditions to Alaska and Canada's Yukon Territory on which he surveyed, photographed and mapped some of the last unexplored mountain regions in North America. This study, however, analyzes Washburn's lesser known role in directing interdisciplinary field research involving high altitude physics, glaciology, cartography and geology, which he accomplished by linking such disparate entities as the motion picture industry, geographic organizations, the U.S. military, and prominent U.S. scientists. Washburn's career can be viewed as an intersection of nineteenth and twentieth century geographic traditions. He combined emerging technologies with new and innovative vehicles of exploration to more accurately study geological, geographical and environmental phenomenon in mountainous regions. During the Second Great Age of Discovery, which began with the Renaissance, explorers ventured into the heart of the world's continents by utilizing various vehicles of exploration such as canoes and pack animals. This style continued into the middle of the twentieth century when the present day Third Great Age of Discovery, characterized by the use of remote sensing platforms and space age satellites, allows for a more accurate geographic study and inventory of our planet. Washburn's interdisciplinary field work reflects the fundamental goals and patterns of expeditionary science found in both ages of discovery. In this study three important themes are examined: Washburn's role as innovative field scientist; geography as a disciplinary bridge; and the work of the independent geographer. By analyzing Washburn's work in the pre World War Two and Cold War era, we gain an understanding of the ways in which expeditionary science was funded and carried out within two fundamentally different political and economic frameworks. Moreover, this study provides an important window into our understanding of interdisciplinary earth sciences in the mid twentieth century. It also explores the often unappreciated link between environmental science and geography in the American context.
    • Disturbance History In The Tanana River Basin Of Alaska: Management Implications

      Roessler, James S.; Packee, Edmond C. (1997)
      The forests of Tanana River Basin in Interior Alaska have a history of disturbance. Four issues reflecting forest disturbance, important to include in current management strategies for these lands, were researched: (1) disturbance history of the Tanana Valley; (2) Alaska Interagency Fire Management Plan: a case study; (3) prescribed natural fire in Alaska: possibilities and complexities; and (4) past use of prescribed fire in white spruce: a summary with particular reference to Alaska. Through researching historical archives, conducting field visits, interviewing land and fire managers and reviewing current planning documents, I reached four major conclusions: (1) there is lack of use of historical facts regarding human-induced changes on the landscapes; (2) past involvement of public stakeholders in fire planning in Alaska was inadequate; (3) the Alaska Interagency Fire Management Plans need to identify scientific prescription parameters which address specific land management objectives; and (4) management-ignited prescribed fire must become a more common prescription after harvesting of white spruce. <p>
    • Experimental And Theoretical Investigation Of Stratospheric Ozone Depletion In The Northern Hemisphere Caused By Heterogeneous Chemistry

      Storvold, Rune; Stamnes, Knut (2001)
      Stratospheric ozone is of crucial importance for life on Earth. This thin layer protects us from the ultraviolet solar radiation and also works as a greenhouse gas that helps maintaining our climate. Large changes in thickness and vertical distribution of the ozone abundance may have detrimental effects on life on Earth. But even small changes could have considerable impact on UV irradiance, bio-production and cancer rates. During the last decade record low spring time vertical column amounts of stratospheric ozone have been observed over Northern Europe. However, this decrease is not as severe as the depletion observed over Antarctica and at mid-latitudes in the Southern Hemisphere. The discovery of the spring time stratospheric ozone depletion first in Antarctica and later in the Arctic has triggered international research efforts on stratospheric ozone chemistry and the possible effects of human activities on the ozone layer. Ground-based differential optical absorption spectroscopy measurements of NO2 and ozone have been performed over Fairbanks (65�N) and Ny-Alesund (79�N) during the 1994--95 season. In this work we present improvements to ground based differential optical spectroscopy measurements by improving dark current corrections and spectral fitting of spectrographic photo diode array detector measurements. We have also improved the retrieval of vertical column amounts from diffuse light measurements by improving the corrections for seasonal changes in absorber air mass. This is particularly important at high latitudes. We used these data together with local weather and ozone sounding data, and with trace gas and aerosol data measured by other ground based instruments and by instruments deployed on satellites. This comprehensive dataset was used to investigate the performance of two current state of the art chemical transport models with and without the presence of heterogeneous chemistry. These are the University of Cambridge SLIMCAT model and the University of Oslo SCTM-1 model. They were selected because the SLIMCAT is designed for process studies and comparison with measured data while the SCTM-1 is designed for prognostic and sensitivity studies aimed at predicting future development of the stratospheric ozone layer. We have used the models to study the sensitivity of the heterogeneous chemistry to stratospheric meteorological conditions and the effect of sulfuric acid aerosols and polar stratospheric clouds on the stratospheric ozone abundance and ozone chemistry at high- and mid-latitudes in the Northern Hemisphere.
    • Landscape Control Of Thunderstorm Development In Interior Alaska

      Dissing, Dorte; Verbyla, David (2003)
      General Circulation Models suggest a future climate of warmer and possibly drier summers in the boreal forest region, which could change fire regimes in high latitudes. Thunderstorm development is a dominant factor in the continental boreal forest fire regime, through its influence as a fire starting mechanism. Global Climate Change research has identified the land-atmosphere interface as a vital area of a needed research in order to improve our predictions of climate change. This dissertation has focused on the development of thunderstorms and lightning strike activity in a boreal forest region in Interior Alaska and on how the underlying surface can influence their development. I have examined the distributions and correlations between lightning strikes, thunderclouds, thunderstorm indices (CAPE and LI), elevation, and vegetation variables in Alaska. The relationships were examined at scales ranging from the Interior region of the state to individual wildfire burn scars, and at temporal scales ranging from the annual to daily. The objective is to understand the influential factors and processes responsible for thunderstorm development in Alaska, such that we may produce well-founded predictions on future thunderstorm regimes caused by a changing climate. The scale-related studies of this dissertation show that both processes and important variables for development of thunderstorms and lightning activity vary within and between the scales. It appears that on the larger scales, the combined effects of boreal forest and elevation on increased lightning strike activity were more prevalent than at the smallest scale (local). When the scale gets too small for the boundary layer to be affected (<10km), land surface effects on lightning cannot be. My results suggest that the underlying surface (in the form of areal forest coverage and vegetation) has more of an influence on convective development on days with airmass storms than on days with synoptic storms.
    • Mapping impacts of education for wilderness management planning

      Foster, Frederick Anthony (1998)
      Wilderness education is considered a key response to abate physical impacts caused by wilderness recreationists, but education's impacts upon the psychological values of wilderness are unknown. This investigation used a wilderness purism scale to measure how minimum impact instruction affects the intensity and quality of a student's wilderness experience and the relation of these expectations and preferences to appreciation, knowledge, and concern for the environment as a whole, i.e., environmental literacy. A wilderness purism scale, a spatial scale, and wilderness management scale measured how wilderness education affects recreationists' limits of unacceptability in wilderness conditions. Effects of wilderness education on multiple perceptions of wilderness specific to particular groups, are explained. Methods of how these can be collected, organized, and mapped using a GIS approach are demonstrated and techniques to build a wilderness experience typology are outlined. The investigation determined that environmental literacy is correlated with wilderness purism. Student's expectations and ethical perspectives toward wilderness became stronger following wilderness leadership education courses, specifically, their perceptions of wildness, experiential factors, and ethical perspectives of the wilderness experience. Educational programs increased respondents' wilderness perceptions and their desired spatial buffer distances from unacceptable conditions in wilderness. Distances from sights and sounds were found to be critical to wildemess recreationists' wilderness experience relating to sensing unacceptable conditions inside wilderness boundaries and "knowing" that unacceptable (human-made) conditions do not exist. Educators may use the findings to better design and assess their program's effectiveness. Results of the methodology could aid Limits of Acceptable Change (LAC) process for wilderness planning. Wilderness managers may use the protocol to plan for the maintenance of wilderness opportunities to meet increasing demands brought about by education. Management must be prepared to protect suitable conditions for this potentially growing population. If managers zone wilderness accordingly to wilderness purism groups, they can protect vast areas from bio/physical impacts by using the processes described in this study. It is a tool for managing wilderness areas for a range of wilderness experiences which will aid in insuring protection of wildlife, ecosystem integrity, and native biodiversity.
    • Microbial ecology and long-term persistence of crude oil in a taiga spruce forest

      Lindstrom, Jon Eric; Braddock, Joan F. (1997)
      The microbial ecology of a 1976 experimental crude oil spill in an Alaskan taiga black spruce forest was investigated in this study. Substantial oil residue remained in the soil, and several microbial parameters showed evidence of long-term oiling effects. Overall, the data suggest that the surviving community in the oiled plot has shifted toward using oil C for growth. Numbers of hydrocarbon degrading microbes, and specific hydrocarbon mineralization potentials, were significantly elevated in the oiled (OIL) plot compared to an adjacent oil-free, reference (REF) plot. Glutamate mineralization potentials and soil C mineralization, on the other hand, were not different between treatments, suggesting that OIL plot heterotrophs were well-acclimated to the oil. Despite little difference between OTL and REF soils in total C mineralized in vitro, net N mineralized was lower and net nitrification was absent in OIL soils. Analysis of the residual oil indicated minimal amounts of N were added with the spilled oil. Biomasses of total fungi and bacteria, and numbers of protozoa, showed no consistent effects due to oiling, but metabolically active fungal and bacterial biomasses were uniformally lower in OTL samples. Community-level multiple substrate metabolism (Biolog) was assessed using a new technique for extracting kinetic data from the microplates. This analysis suggested that the microbial population diversity in the OIL soils was lower than in REF soils. Further, these data indicated that the surviving populations in the OIL plot may be considered metabolic generalists. Some evidence of crude oil biodegradation was seen in the chemistry data, but enrichment of the oil residue in higher molecular weight components, duration of contact with soil organic material, and slow rates of C mineralization indicate the crude oil will persist at this site for decades. Contamination of Alaskan taiga soil at this site has yielded observable long-term microbial community effects with larger-scale consequences for ecosystem function.
    • Millennial To Annual Scale Paleoclimatic Change In Central Alaska During The Late Quaternary Interpreted From Lake Sediments And Tree Rings

      Barber, Valerie Ann; Finney, Bruce; Juday, Glenn (2002)
      The theme of this dissertation is the importance of effective moisture (precipitation minus evaporation) in subarctic ecosystems. Interior Alaska has a relatively dry climate with annual precipitation ranging from 25--45 cm. Records from interior Alaska lake sediment cores show low lake levels following the Last Glacial Maximum, with significant increases at 12,000 and 9,000 14C years BP. Using lake-level reconstructions and models based on modern hydrologic and meteorologic data, we infer precipitation of 35--75% less than modern at 12,000 yr. BP, 25--45% less than modern at 9,000 yr. BP, and 10--20% less than modern at 6,000 yr. BP. Trees were scarce on the interior Alaskan landscape during the late Pleistocene with birch species appearing about 12,000 BP and spruce species approximately 3500 years later. The correspondence between lake-level and vegetation changes suggests that moisture may have been one of the limiting factors in the establishment of these tree species. Alaska climate records show a climatic regime shift in the mid-1970s. Less effective moisture is available over the past 30 years because summer temperatures in interior Alaska have been increasing without a concurrent increase in precipitation. Radial growth of white spruce at 20 low elevation stands in interior Alaska declined corresponding with this climatic change. The observation that moisture limits spruce growth in Alaska today is consistent with our inference of moisture limitation in the early Holocene. A 200-year reconstruction was developed based on two tree ring proxies, 13C discrimination and maximum latewood density, which together show excellent agreement with the recorded Fairbanks average May through August temperatures. The first half of the 20th century is characterized by the coolest summers of the 200 year period of reconstruction, while the latter part of the 20th century, particularly from 1974 onward, is characterized by some of the warmest summers of the 200 year period. Mid-19 th summer temperatures reconstruct to be as warm as the latter part of the 20th century, which is inconsistent with reconstructions of other regions. It seems likely, based on current information, that these inconsistencies may be real and may reflect regional synoptic conditions unique to interior Alaska. Distinctive decadal scale regimes were identified throughout the record.
    • Phenanthrene Adsorption And Desorption By Melanoidins And Marine Sediment Humic Acids

      Terschak, John Andrew; Henrichs, Susan M. (2002)
      Sediments are major reservoirs of persistent petroleum contamination in marine environments. Petroleum hydrocarbons associate with the sediment organic matter, of which humic acids are an important constituent. This study examined the role that humic acid and its structure plays in the kinetics and mechanisms of polycyclic aromatic hydrocarbon (PAH) interactions with sediments. Natural humic acids, with a wide range of properties, were isolated from Alaska coastal marine sediments. Melanoidins were synthesized and used as humic acid analogs. The humic acids were characterized by elemental and isotopic analyses, Fourier transform infrared spectroscopy, and cross-polarized magic angle spinning 13C nuclear magnetic resonance spectroscopy. The humic acids were coated onto a standard montmorillonite clay, and the adsorption and desorption of phenanthrene was measured using a radiotracer. Adsorption required about one week to reach steady state, indicative of slow diffusion of PAH within the humic acid. The composition of the humic acids had a greater effect on phenanthrene adsorption than their concentrations on the clay. Organic carbon normalized adsorption partition coefficients were closely correlated with the sum of amide and carboxylic carbons, a measure of the polarity of the humic acids, but were independent of initial phenanthrene concentration, indicating that the binding sites were unlimited and uniform in strength. This explains the fact that initial adsorbed concentration of phenanthrene had no effect on subsequent phenanthrene adsorption. Desorption of phenanthrene was not related to any of the humic acid structural characteristics measured. The initial desorption rate was linearly related to the initial adsorbed concentration, as expected for a diffusive process, and was negatively correlated with the carbon content of the humic acid coated clay. Under most conditions, desorption was complete after one to seven days; there was little evidence for irreversible adsorption. Because of the substantial variability of adsorption and desorption behavior with organic matter characteristics, interactions of aromatic hydrocarbons with marine sediments cannot be predicted based on total organic matter concentration alone. Information on aspects of organic matter composition is needed in order to make accurate predictions.
    • Relationship between the aerosol number distribution and the cloud condensation nuclei supersaturation spectrum

      Cantrell, Will Hart, Ii; Shaw, Glenn E. (1999)
      Though Cloud Condensation Nuclei (CCN) are a subset of atmospheric aerosol, relatively little is known of what links the two. A recently developed instrument called the CCN Remover, which directly relates the CCN supersaturation spectrum to the aerosol number distribution, is described. Instrumental errors are quantified and laboratory tests used to verify the instrument's accuracy are also presented. We made measurements with the CCN Remover in the Aerosol Characterization Experiment 2 (ACE 2) and the INdian Ocean EXperiment (INDOEX). These two multinational field campaigns shared the objective of investigating aerosol particles' ability to modulate cloud albedo by activating as CCN. In both instances, we found that aerosol particles were not activating with the characteristics of pure ammonium sulfate, which is generally regarded as the major component of the majority of aerosol particles which act as CCN. Either a substantial fraction of the aerosol was not participating in the activation process or the presence of a hydrophobic surface film inhibited water vapor transport. Measurements of the aerosol's chemical composition and hygroscopic growth factors are used to examine these possibilities. Anthropogenic activity is modifying the properties of natural aerosol particles in a way which could affect their ability to act as CCN. We discuss evidence for aerosol particles coated with sulfuric acid in an Arctic air mass in support of this claim. In some instances, the connection between aerosol and CCN can be inferred directly from the aerosol number distribution. Clouds segregate aerosol into two populations---those that act as CCN and those that do not, and when the cloud evaporates, the aerosol number distribution bears the signature of the cloud through which it has cycled---a minimum in the aerosol number distribution. The diameter at which this minimum occurs can be related to the maximum supersaturation in the cloud, and the number of particles larger than the minimum is the population of particles that acted as CCN. Over 1,000 bimodal aerosol number distributions from five widely separated locations have been analyzed for maximum supersaturation and cloud droplet (or CCN) et (or CCN) concentrations.
    • Studies of gravity-wave filtering and tidal interaction in the middle atmosphere

      Lu, Wentong; Smith, Roger W.; Fritts, David C.; Shaw, Glen E.; Lee, Lou-Chuang; Musgrave, David L.; Watkins, Brenton J. (1993)
      Based on the spectral character of the observed gravity wave field, a parameterization scheme for gravity wave propagation and effects in the lower and middle atmosphere has been proposed. This effort begins with spectral expressions for gravity wave energy and momentum fluxes and prescribes the manner in which such idealized spectra respond to variations in the gravity wave environment. Means of specifying spectral amplitudes in response to specific wave sources at lower levels and the spread of wave influences horizontally as the spectrum propagates vertically through the lower and middle atmosphere are suggested. The parameterization scheme relies on a separable and invariant spectral form that is consistent with observations throughout the atmosphere. By choosing representative gravity wave parameters, the scheme yields predictions of mean fluxes of momentum for winter and summer CIRA 1986 model atmosphere profiles that agree well with mean flux observation in the lower and middle atmosphere. In the troposphere and lower stratosphere, both winter and summer profiles imply a negative zonal mean flux of $\sim$0.2$m\sp2s\sp{-2},$ consistent with airborne and radar measurements and the needs of large-scale GCM models. In the mesosphere, mean fluxes tend to oppose the zonal mean wind with flux maxima above the wind maxima and vertical profiles in general agreement with radar estimates at these heights. To assess the importance of gravity wave-tidal interactions in the middle atmosphere, the parameterization scheme is further applied to a static mean wind plus a typical tidal wind structure. The results suggest that the gravity wave-tidal interaction is likely to be strong where tidal amplitudes become large, yielding a significant modulation in the anisotropy of the gravity wave field due to differential filtering and saturation processes. Consistent with observations, this filtering leads to wave momentum fluxes that are approximately anti-correlated with the tidal wind field and which may far exceed mean values in magnitude.
    • The Campaign To Establish A Last Great Wilderness: The Arctic National Wildlife Range

      Kaye, Roger W.; Gladden, James (2005)
      In 1960, after nearly a decade of controversy and failed legislative attempts, the Arctic National Wildlife Range was established by an executive order "for the purpose of preserving unique wildlife, wilderness, and recreational values." This is the story of the transformation of this little-known expanse of mountains, forest, and tundra into a place internationally recognized as one of the finest examples of wilderness. This dissertation is a political history of the conflict, examining the roles of key proponents and opponents and the sequence of actions that finally brought the Secretary of Interior to issue the order. More important, it is an exploration of the historic, cultural, philosophical, and scientific underpinnings of the campaign. It focuses upon the beliefs and values, the ideas and idealism, and the hopes and concerns for the future that inspired leaders of the effort, captured the public imagination, and galvanized the political support necessary to overcome powerful opposition. The immediate context of the campaign was the post-World War II transformation of American society. More than in any previous period, postwar America was receptive to the idea of setting an area aside for a unique combination of tangible and intangible values---cultural, symbolic, and spiritual values as well as wildlife, ecological, and recreational values. The controversy reflected growing concerns about the era's unprecedented rate of population growth; economic, industrial, and technological expansion; and consequent environmental alteration. For proponents, it came to symbolize the conflict between seemingly unbridled progress and the need to more carefully consider the environmental consequences of these trends. For opponents, the nine-million acre reservation represented a threat to the new state's economic prosperity, resented federal control of natural resources, and a restriction of the opportunity and freedom they came to Alaska seeking. Rooted in the progressive era split between utilitarian conservation and nature preservation, the campaign was, to a large degree, a contest between competing views of the appropriate relationship between postwar American society and its changing landscape. The view that prevailed reflects the successful integration of the emerging ecologically-based "environmental" perspective into the wilderness movement.
    • The effect of ultrasound on polycyclic aromatic hydrocarbons in aqueous media

      Wheat, Patrick E.; Tumeo, Mark; Brown, Edward; Johnson, Ronald; Reichardt, Paul; Tilsworth, Timothy (1992)
      Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants which pose a potential threat to human health and environmental quality. An investigation to determine the ability of ultrasonic radiation to desorb PAHs adsorbed on the surface of solid substrates and to chemically alter these chemicals in aqueous solutions and suspensions has been conducted. The data indicate that enhanced transport of adsorbed PAH from a glass surface can be induced by treatment with ultrasonic radiation of varying intensities. Furthermore, chemical alteration can be induced under intense (147 watts/cm$\sp2)$ ultrasonic treatment. The extent of reaction is a function of irradation time at this ultrasonic intensity. Reaction products from ultrasonic treatment of aqueous solutions of biphenyl, analysed by gas chromatography (GC) and mass spectrometry (MS), include ortho-, meta-, and para-(1,1 biphenyl) -ol. The principal product from ultra-sonic treatment of aqueous phenanthrene appears to be a phenanthrenediol. The use of ultrasound to treat PAH contaminated aqueous solutions in tandem with other methodologies appears promising. However, the toxicity of reaction product mixtures produced by ultrasonic treatment remains to be determined.