• Rabies Alaska and Canada

      Huettmann, Falk; Huettmann, Falk (2021)
    • Rabies data for Canada and Alaska/US for GIS model predictions

      Hueffer, K.; Huettmann, F. (2020-04)
      This value-added data set is part of a publication by Huettmann and Hueffer (in prep) and includes the GIS layers for rabies and predictions of Canada, assessed with Alaska locations ((taken from Huettmann et al. 2015). This project compiled the best publically available rabies data for Canada, and models them for the Northern part of the the North American continent (Alaska and Arctic Canada). The environmental data sets are in a common GIS format (ESRI and ASCII grids) and are taken from public Open Access sources. The rabies data sets are point data, as rabies was reported by the Canadian Food Inspection Agency, and processed in the lab. The dataset is 5GB in size and consists of 20 files.
    • Rabies Virus In Arctic Fox (Vulpes Lagopus): A Study Of Pantropic Distribution

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

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

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

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

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

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

      Iceman, Kimberly Erin; Harris, Michael; Edmonds, Brian; O'Brien, Kristin; Taylor, Barbara (2013)
      Central chemosensitivity is the vital ability of the brain to detect and respond to changes in tissue CO<sub>2 /pH. Changing CO<sub> 2 /pH causes brainstem central chemoreceptors to modulate ventilation, but the cellular basis of this chemosensitivity is not well understood. When studied in vitro, neurons within the rat medullary raphe are intrinsically sensitive to changes in pH. Serotonin/ substance P (5-HT) synthesizing raphe neurons are stimulated, and gamma-aminobutyric acid (GABA) synthesizing neurons are inhibited by CO<sub>2 /acidosis. The contribution of these neurons to central chemosensitivity in vivo, however, is controversial. Also unknown is whether there are other types of chemosensitive cells in the raphe. Here I tested the hypothesis that rat medullary raphe neurons are responsive to CO<sub>2 in a relatively intact preparation, that raphe 5-I-IT neurons are CO<sub> 2-stimulated, and that CO<sub>2inhibited raphe neurons are GABAergic. I used extracellular recording of individual raphe neurons in the unanesthetized juvenile rat in situ perfused decerebrate brainstem preparation to assess chemosensitivity of raphe neurons. I subsequently used juxtacellular labeling, and immunohistochemistry for markers of 5-HT and GABA synthesis to identify neurotransmitter phenotype of individually recorded cells. Results demonstrate that the medullary raphe is heterogeneous and clearly contains at least three distinct classes of CO<sub>2-sensitive neurons: modestly CO<sub>2-stimulated 5-I-IT neurons, CO<sub>2-inhibited GABAergic neurons that possess this sensitivity independent of major fast synaptic inputs, and robustly CO<sub>2-stimulated non-5-HT neurons. The CO<sub>2-stimulated non-5-HT neurons constitute a previously unrecognized class of chemosensitive raphe neuron that express receptors for substance P and are dependent on network inputs from 5-HT and GABA raphe cells for chemoresponsiveness. Based on my identification of these three distinct types of chemosensitive raphe cells, I propose a new raphe chemosensory amplifier (RCA) network model to explain raphe contributions to central chemosensitivity. In this model the three cell types interact as a CO<sub> 2-sensing network that potentially amplifies the chemosensory responses to CO<sub>2 and may limit toxic over excitation of 5-HT neurons. In this way, the RCA network could integrate inputs and respond to changes in tissue CO<sub>2 with an appropriate modulation of sympathetic and/or parasympathetic outflow, consistent with the broad role that brainstem raphe nuclei play in maintaining homeostasis.
    • Rapid Assessment Biodiversity Grid Data for a farming field in Lumbini, Nepal, June 2015

      Huettmann, Falk; Karmacharya, Dikpal; Spangler, Mark (EWHALE Lab, University of Alaska Fairbanks, 2015-06-27)
      This dataset consists of a rapid biodiversity assessment at a farming site near a village in Lumbini, Nepal. The data include 25 plots spaced 100m apart from each other, and 5 additional random points. The geo-referencing was done with a GPS, a geographic datum of WGS84 was used with decinal degrees (5 decimals) of latitude and longitude. The bounding box of this data set is: 27.481920 to 27.486120 Northern latitude, and 83.261799 to 83.266640 Western longitude. The grid was visited three times from June 7th, 8th and 9th in 2015 allowing for occupancy and distance sampling abundance estimates. Point transects were carried out for bird sightings; the insects and vegetation (flowers) were briefly assessed. Two photos were taken for each grid plot, and one sky shot to capture the atmospheric light conditions, e.g. for Remote Sensing work.Noteworthy are the high occurrences of crows, black kites, myrnas and larks, as well the detection of sarus cranes in this landscape that is dominated by domesticated zebu, water buffalo and goats. The grid area was heavily used by humans, e.g. for walking and sanitary purposes. A high incidence of microplastics was found. At the time of survey a heat wave over up to 47 degree Celsius was measured. This dataset consists of an MS Excel sheet and is less than 1MB in size.
    • Rapid Assessment Biodiversity Grid Data for Broad Pass 'divide' in Denali Preserve, Alaska, U.S., July 2016

      Huettmann, Falk; Andrew, Phillip (EWHALE lab, Inst of Arctic Biology, Biology & Wildlife Dept., University of Alaska Fairbanks (UAF), 2016-07)
      This data set consists of a citizen-science type rapid biodiversity assessment at landscape watershed divide in Denali Preserve, Alaska, U.S..The data include 25 plots spaced 100m apart from each other, and 5 additional random points. The geo-referencing was done with a GPS, a geographic datum of WGS84 was used with decimal degrees (5 decimals) of latitude and longitude. The bounding box of this data set is: 63.33421 til 63.33847 Northern latitude, and 149.10451 til 149.11398 Western longitude. The grid was visited three times from July 7th, 8th and 9th in 2016 allowing for occupancy and distance sampling abundance estimates for instance. Point transects were carried out for bird sightings; the vegetation (flowers and trees) and insects (trapping web of 100 cups) were briefly assessed. Three photos were taken for each grid plot, including one sky shot to capture the atmospheric light conditions, e.g. for Remote Sensing work. Noteworthy are the high occurrences of moose browse, as well as savannah and white-crowned sparrows. Despite its esthetic landscape appeal, the grid area was heavily affected by humans, e.g. a highway, local airport and railway and a camp ground are located at the grid. Incidence of hunting and snowmobiling was found. Basic weather data were also collected for 24h during the survey period. This dataset consists of an MS Excel sheet and is less than 1MB in size.
    • Rapid Assessment Biodiversity Grid Data for Snow Leopard and Pallas Cat habitats in Manang, Annapurna Conservation Area, Nepal, early June 2015

      Huettmann, Falk; Lama, Rinzin Phunjok; Ghale, Tashi R. (EWHALE Lab, University of Alaska Fairbanks, 2015-06-27)
      This dataset consists of a rapid biodiversity assessment at a Snow Leopard (Panthera uncia) and Pallas Cat (Otocolobus manul) habitat site near Manang village in the Annapurna Conservation Area (ACA), Nepal. The data include 25 plots spaced 100m apart from each other, and 5 additional random points. The geo-referencing was done with a GPS, a geographic datum of WGS84 was used with decinal degrees (5 decimals) of latitude and longitude. The bounding box of this data set is: 27.691960 to 28.287450 Northern latitude, and 84.004010 to 83.998410 Western longitude. The grid is located on a slope app. on 4200m above sea level and was visited three times on May 30th, May 31st and June 1st in 2015 allowing for occupancy and distance sampling abundance estimates. Point transects were carried out for bird sightings; animal tracks, insects (butterflies) and vegetation (flowers) were briefly assessed. Two photos were taken for each grid plot, and one sky shot to capture the atmospheric light conditions, e.g. for Remote Sensing work.Noteworthy are the high grazing pressures and strong occurrences of yaks, horses, and goats, as well the detection of bharal (blue sheep), Lammergeier, Himalaya Griffon, Golden Eagle, snow cock, cockoo, pipits and wagtails in this mountain high altitude landscape (all scientific names and details are provided in the taxonomic section of the metadata). Small white snails were found too. A snowleopard kill site (blue sheep and yak) was found, as well as tracks and a resting site on a nearby higher cliff site (where Pallas Cat was also observed earlier). This dataset consists of an MS Excel sheet and is less than 1MB in size.
    • Rapid Assessment Biodiversity Grid Data for ‘Lueneburger Heide’ (Lueneburg Heathland), Schneverdingen, Germany, August 2015

      Huettmann, Falk (2015-08)
      This data set consists of a citizen-science type rapid biodiversity assessment at landscape of ‘Lueneburger Heide’ (Lueneburg Heathland) near Schneverdingen, Germany.The data include 25 plots regularly spaced 100m apart from each other, and 5 additional random points. The geo-referencing was done with a GPS, a geographic datum of WGS84 was used with decimal degrees (5 decimals) of latitude and longitude. The bounding box of this data set is: 53.03996 til 53.10003 Northern latitude, and 9.80769 til 9.81478 Western longitude. The grid was visited three times between August 8th til 12th in 2015 allowing for occupancy and distance sampling abundance estimates for instance. Point transects were carried out for bird sightings. Also, mammalian evidence, the vegetation (flowers and trees) and some insects (primarily ants) were briefly assessed. Three photos were taken for each grid plot, including one sky shot to capture the atmospheric light conditions, e.g. for Remote Sensing work. Noteworthy are the high occurrences of human impacts (biofuel mais and tree plantations, sheep farming “Heidschnucken’, tourism, local train), as well as songbirds. Despite its esthetic and highly managed heath landscape appeal, the grid area is essentially a highly frequented surban nature recreation reserve but avian raptors, common cranes, rare amphibians (moor frog, roe deer, boar and re-introduced wolf can be found! Incidence of hunting occurs (e.g. high stands). This dataset consists of an MS Excel sheet and is less than 1MB in size.
    • Rapid Biodiversity Assessment GRID Sampling (citizen science) in the White Mountains, northern Alaska, USA, June 2013

      Huettmann, Falk (2013-07-03)
      This data set consists of a Rapid Biodiversity Sampling from a non-intrusive citizen science GRID (5*5 geo-referenced sampling + 5 random plots = 30 plots overall). It includes raw count data for 305 bird observations of 14 identified bird species, and plants from the 25+5 survey sampling plots (3m radius), as well as insects from four trapping webs (3m radius, 25 traps each, 3 repeats; mostly spiders were detected). The survey was done between 25th of June and 27th of June in 2013 at the White Mountains (north to the NorthForkBirch and Twelvemile Creeks - near the Steese Hgw 6) in Alaska USA (decimal degrees latitude 65.39590, longitude -145.72890, geographic datum of WGS84) . Plots are located near the public road in the rolling hills, subartic tundra on some slope, and some are located. All plot locations were photographed (sky, ground and habitat shots) and for a visual assessment. All bird detections (visual and oral) carry a radial distance 360 degrees from the observer, and were collected according to DISTANCE Sampling point transect protocols. Respectively, a DISTANCE Sampling trapping web protocol, with a 3m radius and allowing for detectability correction in abundance estimates, was applied for ground-living insects. Generally, these data do not cover high detailed taxonomic information (and usually just follow basic but accurate descriptions). Each plot was visited three times according to the PRESENCE software requirements to obtain occupancy estimates. All of these data can be data-mined using for instance freely available RandomForest, Distance Sampling and PRESENCE software packages. Comparable Biodiversity GRID data so far is available for over 11 other regions (e.g. Nicaragua, Central Alaska, Costa Rica, Papua New-Guinea, Northern & Interior Alaska, Northeastern China and Russian Far East). Data from the other study sites are also available online. For more details please contact authors. The fllowing species were identified: dwarf birch (Betula nana Taxonomic Serial Number TSN by ITIS.org 19479), Black crowberry (Empetrum nigrum 23743), Cottongrass (Eriophorum 40079), marsh Labrador tea (Rhododendron tomentosum 894434), Alaska blue berry (Vaccinium ovalifolium 23607), Bird vetch (Vicia cracca 26335), Ant (Formica 154211), Bohemian Waxwing (Bombycilla garrulus 178529), Fox Sparrow (Carduelis flammea 179230), Gray Jay (Perisoreus canadensis 179667), Swainson`s Thrush (Catharus ustulatus 179788), Raven (Corvus corax 179725), Yellow-rumped Warbler (Dendroica coronata 178891), Savannah Sparow (Passerculus sandwichensis 179314), Fox Sparrow (Passerella iliaca 179464), Grouse (Phasianidae 175861), Woodpecker (Picidae 178148), American Robin (Turdus migratorius 179759), Wilson Warbler (Wilsonia pusilla 178973), White-crowned Sparrow (Zonotrichia leucophrys 179455), Common Redpoll (Carduelis flammea 179230).
    • Rapid multi-nation distribution assessment of a charismatic species of conservation concern using ensemble model predictions: The Red Panda in the Hindu-Kush Himalaya region

      Kandel, Kamal; Suwal, Madan Krishna; Regmi, Ganga Ram; Nijman, Vincent; Nekaris, K.A.I.; Lama, Sonam Tashi; Thapa, Arjun; Sharma, Hari Prasad; Subedi, Tulsi Ram; Huettmann, Falk (2013)
      Background The red panda (Ailurus fulgens) is a globally threatened species living in the multi-nation Hindu-Kush Himalaya (HKH) region. It has a declining population trend due to anthropogenic pressures. Additionally, human-driven climate change is expected to have substantial impacts on the fragmented populations and the fragile habitats throughout its range. However, quantitative and transparent information on the ecological niche (potential as well as realized) of this species and the distribution across the vast and complex eight nations of the HKH region is still lacking. Such baseline information is not only crucial for identifying new populations but also for restoring locally extinct populations and for understanding its bio-geographical evolution, as well as for prioritizing regions and efficient management actions. Our study presents the first quantitative large-scale prediction of the potential ecological niche of red panda for the entire HKH. Methodology/Principal Findings We compiled, and made publicly available the best known ‘presence only’ red panda dataset with ISO compliant metadata. This was done through the International Centre for Integrated Mountain Development (ICIMOD.org) data-platform to the Global Biodiversity Information Facility (GBIF.org). We used data mining and machine learning algorithms such as high-performance commercial Classification and Regression Trees (CART), Random Forest, TreeNet, and Multivariate Adaptive Regression Splines (MARS) implementations (Salford Systems Ltd). We averaged all these models for the first produced Ensemble Model for HKH as well as for this species. Conclusions/Significance Our predictive model allows finding major drivers of the red panda ecological distribution niche, as well as to assess and fine-tune earlier habitat area estimates for management. Our models can be used by the Red Panda Recovery Team, Red Panda Action Plan etc. because they are robust, transparent, publicly available, fit for use, and have a good accuracy, as judged by several metrics e.g. Receiver Operating Characteristics (ROC-AUC) curves, expert opinion and assessed by known absence locations
    • Rapid thinning and collapse of lake calving Yakutat Glacier, Southeast Alaska

      Motyka, Roman; Hock, Regine; Larsen, Christopher; Trüssel, Barbara Lea; Truffer, Martin (2013-12)
      Glaciers around the globe are experiencing a notable retreat and thinning, triggered by atmospheric warming. Tidewater glaciers in particular have received much attention, because they have been recognized to contribute substantially to global sea level rise. How-ever, lake calving glaciers in Alaska show increasingly high thinning and retreat rates and are therefore contributors to sea level rise. The number of such lake calving systems is increasing worldwide as land-terminating glaciers retreat into overdeepened basins and form proglacial lakes. Yakutat Glacier in Southeast Alaska is a low elevation lake calving glacier with an accumulation to total area ratio of 0.03. It experienced rapid thinning of 4.43 ± 0.06 m w.e. yr⁻¹ between 2000-2010 and terminus retreat of over 15 km since the beginning of the 20th century. Simultaneously, adjacent Yakutat Icefield land-terminating glaciers thinned at lower but still substantial rates (3.54 ± 0.06 m w.e. yr⁻¹ for the same time period), indicating lake calving dynamics help drive increased mass loss. Yakutat Glacier sustained a ~3 km long floating tongue for over a decade, which started to disintegrate into large tabular icebergs in 2010. Such floating tongues are rarely seen on temperate tidewater glaciers. The floating ice was weakened by surface ablation, which then allowed rifts to form and intersect. Ice velocity from GPS measurements showed that the ice on the floating tongue was moving substantially faster than grounded ice, which was attributed to rift opening between the floating and grounded ice. Temporal variations of rift opening were determined from time-lapse imagery, and correlated well with variations in ice speeds. Larger rift opening rates occurred during and after precipitation or increased melt episodes. Both of these events increased subglacial discharge and could potentially increase the subaqueous currents towards the open lake and thus increase drag on the ice underside. Simultaneously, increased water input may cause lake level in rifts to rise resulting in faster rift propagation and spreading. Similar formation and disintegration of floating tongues are expected to occur in the glacier's future, as the ice divide lies below the current lake level. In addition to calving retreat, Yakutat Glacier is rapidly thinning, which lowers its surface and therefore exposes the ice to warmer air temperatures causing increased thinning. Even under a constant climate, this positive feedback mechanism would force Yakutat Glacier to quickly retreat and mostly disappear. Simulations of future mass loss were run for two scenarios, keeping the current climate and forcing it with a projected warming climate. Results showed that over 95% of the glacier ice will have disappeared by 2120 or 2070 under a constant vs projected climate, respectively. For the first few decades, the glacier will be able to maintain its current thinning rate by retreating and thus losing areas of lowest elevation. However, once higher elevations have thinned substantially, the glacier cannot compensate any more to maintain a constant thinning rate and transfers into an unstable run-away situation. To stop this collapse and transform Yakutat Glacier into equilibrium in its current geometry, air temperatures would have to drop by 1.5 K or precipitation would have to increase by more than 50%. An increase in precipitation alone is unlikely to lead to a stable configuration, due to the very small current accumulation area.
    • Rapid Uplift Of Southern Alaska Caused By Recent Ice Loss

      Larsen, Christopher Fairlamb; Freymueller, Jeffrey T. (2003)
      Changing surface loads, such as melting glaciers, can induce deformation of the Earth's crust. The speed of the Earth's response to load changes and the pattern of deformation they cause can be used to infer material properties of the lithosphere and mantle. Rapid uplift of southern Alaska has been measured with tide gauges, Global Positioning System (GPS) measurements and studies of raised shorelines. With multiple sites uplifting at rates in excess of 25 mm/yr, these measurements reveal the world's fastest regional uplift. Southern Alaska has over 75000 km2 of glaciers, the rapid melting of which is contributing more to global sea level rise than Greenland. Southern Alaska also has intense tectonic activity, and uplift driven by tectonics has been suggested to be comparable with that driven by glacial unloading. The majority of the uplift measurements examined here are located along the strike-slip portion of the Pacific - North America plate boundary. GPS measurements show little compressional strain associated with tectonic forcing. Tide gauges indicate long term linear uplift rates within the strike-slip regime, contrasting with tectonically influenced non-linear uplift to the northwest, where the Pacific Plate subducts beneath North America. Dating of raised shorelines within southeast Alaska show that the rapid uplift there began simultaneously with glacial unloading ~1790 AD. These observations indicate that the tectonic contribution to the uplift in southeast Alaska is small. Multiple independent studies are used here to constrain the load changes in southern Alaska over the past ~1000--2000 yrs. A detailed model of the advance, standstill and retreat phases of the Little Ice Age glaciation is used as input to a simple viscoelastic Earth model. This model can match the pattern and magnitude of the region's uplift observations with a low degree of misfit, verifying that the region's uplift can be entirely attributed to glacial isostatic rebound. Furthermore, the uplift observations require at the 95% confidence level a three-layer Earth model consisting of a <math> <f> 50<sup>+30</sup><inf>-25</inf></f> </math> km thick elastic lithosphere, an asthenosphere with viscosity eta A = (1.4 +/- 0.3) x 1019 Pa s and thickness <math> <f> 110<sup>+20</sup><inf>-15</inf></f> </math> km, overlaying a viscous upper mantle half-space (etaum = 4 x 1020 Pa s).
    • Rayleigh lidar studies of mesospheric inversion layers at Poker Flat Research Range, Chatanika, Alaska

      Irving, Brita K. (2012-08)
      Rayleigh lidar observations at Poker Flat Research Range, Chatanika, Alaska (65°N, 213°E), have yielded density and temperature measurements from 40-80 km. These measurements have been made under clear nighttime skies since November 1997. This thesis presents a study of Mesospheric Inversion Layers (MILs) and lidar performance at Chatanika. MILs are identified and characterized in the 40-70 km altitude region on 55 of the 149 wintertime observations over two periods, November 1997-April 2005 and November 2007-March 2009, using a new detection algorithm. Investigation of the MILs compared with planetary wave activity as observed by satellite finds a strong correlation between the presence of MILs and the structure of the planetary waves. These two periods are marked by strong planetary wave activity and sudden stratospheric warming events. MILs are found to occur more frequently than previously reported at Arctic sites, but less frequently than at lower latitudes. In spring 2012 the existing lidar system was extended by incorporating a larger aperture telescope and higher power laser and field trials were conducted. The results from these field trails are presented and the ability of the new lidar system to extend the scope of future studies at Chatanika is assessed.
    • Recent changes in plant and avian communities at Creamer's Refuge, Alaska using field and remote sensing observations

      Tauzer, Lila Maria; Powell, Abby; Bret-Harte, Syndonia; Sharbaugh, Susan; Prakash, Anupma (2013-05)
      Plant communities in the north are being profoundly altered by climate warming, but our understanding of the extent and outcomes of this ecosystem shift is limited. Although it was assumed local vegetation changes will affect avian communities, few data exist to investigate this relationship. In an interior Alaska boreal forest ecosystem, this study capitalized on available resources to assess simultaneous change in plant and avian communities over 35 years. Biological changes were quantified in summer avian community data (species composition, diversity, and richness) and in vegetation using archived field data, and supplemented this data with remote sensing observations for a similar time period to assess the validity of this method for documenting environmental change. Field and remote sensing data both documented successional changes resulting in denser, more coniferous-dominated habitats. Birds responded accordingly, which indicates a rapid avian response to habitat change and that they are good indicators of environmental change. Information gained provides more accurate evaluations of habitat dynamics throughout the interior boreal forest and highlights the importance of considering successional change in all long-term climate studies. It allows for better predictions of future habitat change and acts as a strong baseline for future environmental monitoring.