508 research outputs found
Communication Scholarship and the Quest for Open Access
The advent of black, green, and gold open access publication models poses unique questions for scholars of communication. Platoās (1956) classic critique of writing in the legend of Theuth and Thamus warned that the printed word ārolls about all over the place, falling into the hands of those who have no concern with itā (pp. 69ā70). More than two 2 millennia later, scholars and administrators at all levels of the discipline face just such a phenomenon. As scholars of cyberspace debate whether āinformation wants to be freeā (Levy, 2014), a communication perspective involves consideration of the importance of authorship and attribution amid an ever-shifting array of digital publishing options and subversions. The purpose of this study is to investigate the ongoing transformation of academic publishing by examining black, green, and gold open access models, the responses of the communication discipline, and ongoing questions surrounding the nature and extent of accessibility. As access options for research and publication continue to evolve, this study hopes to provide coordinates for administrators seeking to navigate questions concerning the what, how, and why of communication scholarship in a digital age
Bering Strait transports from satellite altimetry
TOPEX/POSEIDON altimetry data are used to compute sea level slopes across the Bering Strait and associated geostrophic transport anomalies through the strait during ice-free periods from 1992 to 2002. The satellite turning latitude near 66N is just north of the strait, allowing us to use data from seven nearly zonal altimeter tracks close to the strait and to provide estimates of mean slopes, geostrophic currents and water transports approximately every 1.5 days. The altimeter-derived transport anomalies far exceed the mean value and are in good agreement with those derived from in situ observations. Comparison to wind data from a nearby meteorological station in Uelen, Russia, shows that computed transport anomalies correlate well with strong along-strait winds and less so with winds from other directions, thus making the transport predictions from winds alone more successful in seasons with strong and persistent meridional winds
Surface salinity under transitioning ice cover in the Canada Basin: Climate model biases linked to vertical distribution of fresh water
The Canada Basin has exhibited a significant trend toward a fresher surface layer and thus a more stratified upper-ocean over the past three decades. State-of-the-art ice-ocean models, by contrast, tend to simulate a surface layer that is saltier and less stratified than observed. Here, we examine decadal changes to seasonal processes that may contribute to this wide-reaching model bias using climate model simulations from the Community Earth System Model and below-ice observations from the Arctic Ice Dynamics Joint Experiment in 1975 and Ice Tethered Profilers in 2006-2012. In contrast to the observations, the models simulate salinity profiles that show relatively little variation between 1975 and 2012. We demonstrate that this bias can be mainly attributed to unrealistically deep vertical mixing in the model, creating a surface layer that is saltier than observed. The results provide insight for climate model improvement with broad implications for Arctic sea ice and ecosystem dynamics
Arctic system on trajectory to new state
The Arctic system is moving toward a new state that falls outside the envelope of glacial-interglacial fluctuations that prevailed during recent Earth history. This future Arctic is likely to have dramatically less permanent ice than exists at present. At the present rate of change, a summer ice-free Arctic Ocean within a century is a real possibility, a state not witnessed for at least a million years. The change appears to be driven largely by feedback-enhanced global climate warming, and there seem to be few, if any processes or feedbacks within the Arctic system that are capable of altering the trajectory toward this āsuper interglacialā state
A Steady Regime of Volume and Heat Transports in the Eastern Arctic Ocean in the Early 21st Century
Mooring observations in the eastern Eurasian Basin of the Arctic Ocean showed that mean 2013ā2018 along-slope volume and heat (calculated relative to the freezing temperature) transports in the upper 800 m were 4.8 Ā± 0.1 Sv (1 Sv = 106 m3/s) and 34.8 Ā± 0.6 TW, respectively. Volume and heat transports within the Atlantic Water (AW) layer (ā¼150ā800 m) in 2013ā2018 lacked significant temporal shifts at annual and longer time scales: averaged over the two periods of mooring deployment in 2013ā2015 and 2015ā2018, volume transports were 3.1 Ā± 0.1 Sv, while AW heat transports were 31.3 Ā± 1.0 TW and 34.8 Ā± 0.8 TW. Moreover, the reconstructed AW volume transports over longer, 2003ā2018, period of time showed strong interannual variations but lacked a statistically significant trend. However, we found a weak positive trend of 0.08 Ā± 0.07 Sv/year in the barotropic AW volume transport estimated using dynamic ocean topography (DOT) measurements in 2003ā2014 ā the longest period spanned by the DOT dataset. Vertical coherence of 2013ā2018 transports in the halocline (70ā140 m) and AW (ā¼150ā800 m) layers was high, suggesting the essential role of the barotropic forcing in constraining along-slope transports. Quantitative estimates of transports and their variability discussed in this study help identify the role of atlantification in critical changes of the eastern Arctic Ocean.publishedVersio
Mesoscale Atlantic water eddy off the Laptev Sea continental slope carries the signature of upstream interaction
A mesoscale eddy formed by the interaction of inflows of Atlantic water (AW) from Fram Strait and the Barents Sea into the Arctic Ocean was observed in February 2005 off the Laptev Sea continental slope by a mooring equipped with a McLane Moored Profiler. The eddy was composed of two distinct, vertically aligned cores with a combined thickness of about 650 m. The upper core of approximately ambient density was warmer (2.6Ā°C), saltier (34.88 psu), and vertically stably stratified. The lower core was cooler (0.1Ā°C), fresher (34.81 psu), neutrally stratified and ā¼0.02 kg/m3 less dense than surrounding ambient water. The eddy, homogeneous out to a radius of at least 3.4 km, had a 14.5 km radius of maximum velocity, and an entire diameter of about 27 km. We hypothesize that the eddy was formed by the confluence of the Fram Strait and Barents Sea AW inflows into the Arctic Ocean that takes place north of the Kara Sea, about 1100 km upstream from the mooring location. The eddy's vertical structure is likely maintained by salt fingering and diffusive convection. The numerical simulation of one-dimensional thermal and salt diffusion equations reasonably reproduces the evolution of the eddy thermohaline patterns from the hypothesized source area to the mooring location, suggesting that the vertical processes of double-diffusive and shear instabilities may be more important than lateral processes for the evolution of the eddy. The eddy is able to carry its thermohaline anomaly several thousand kilometers downstream from its source location
Group interventions to improve health outcomes : a framework for their design and delivery
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Connections among ice, runoff and atmospheric forcing in the Beaufort Gyre
During SHEBA, thin ice and freshening of the Arctic Ocean surface in the Beafort Sea led to speculation that perennial sea ice was disappearing [McPhee et al., 1998]. Since 1987, we have collected salinity, Ī“Ā¹āøO and Ba profiles near the initial SHEBA site and, in 1997, we ran a section out to SHEBA. Resolving fresh water into runoff and ice melt, we found a large background of Mackenzie River water with exceptional amounts in 1997 explaining much of the freshening at SHEBA. Ice melt went through a dramatic 4-6 m jump in the early 1990s coinciding with the atmospheric pressure field and sea-ice circulation becoming more cyclonic. The increase in sea-ice melt appears to be a thermal and mechanical response to a circulation regime shift. Should atmospheric circulation revert to the more anticyclonic mode, ice conditions can also be expected to revert although not necessarily to previous conditions.Copyrighted by the American Geophysical Union
Toward quantifying the increasing role oceanic heat in sea ice loss in the new Arctic
Author Posting. Ā© American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 96 (2015): 2079ā2105, doi:10.1175/BAMS-D-13-00177.1.The loss of Arctic sea ice has emerged as a leading signal of global warming. This, together with acknowledged impacts on other components of the Earth system, has led to the term āthe new Arctic.ā Global coupled climate models predict that ice loss will continue through the twenty-first century, with implications for governance, economics, security, and global weather. A wide range in model projections reflects the complex, highly coupled interactions between the polar atmosphere, ocean, and cryosphere, including teleconnections to lower latitudes. This paper summarizes our present understanding of how heat reaches the ice base from the original sourcesāinflows of Atlantic and Pacific Water, river discharge, and summer sensible heat and shortwave radiative fluxes at the ocean/ice surfaceāand speculates on how such processes may change in the new Arctic. The complexity of the coupled Arctic system, and the logistic and technological challenges of working in the Arctic Ocean, require a coordinated interdisciplinary and international program that will not only improve understanding of this critical component of global climate but will also provide opportunities to develop human resources with the skills required to tackle related problems in complex climate systems. We propose a research strategy with components that include 1) improved mapping of the upper- and middepth Arctic Ocean, 2) enhanced quantification of important process, 3) expanded long-term monitoring at key heat-flux locations, and 4) development of numerical capabilities that focus on parameterization of heat-flux mechanisms and their interactions.2016-06-0
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