Renaming and Rebranding within U.S. and Canadian Geography Departments, 1990–2014     

Amy E. Frazier  Thomas A. Wikle 《The Professional geographer》2017,69(1):12-21

Between 2000 and 2014, more than thirty geography departments adopted revised or new names, with some entirely dropping geography. Although renaming and rebranding efforts are not new to higher education, the rapid pace at which geography department names have changed raises questions about the discipline's identity and health. We examine the renaming trend within geography programs together with intended and unexpected factors as perceived by faculty. Specifically, we look at the renaming and rebranding trend within the context of four pillars offered by Pattison (1964 Pattison, W. D. 1964. The four traditions of geography. Journal of Geography 63 (5): 211–16.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) to define geography's principal academic domains—earth-science, man–land, area/regional studies, and spatial traditions.  相似文献   

Importance of organic Fe complexing ligands in the Mississippi River plume     

Rodney T. Powell  Amy Wilson-Finelli 《Estuarine, Coastal and Shelf Science》2003,58(4):757

As part of a larger program focused on understanding the biogeochemistry of large river plumes, we participated in two expeditions during 2000 to sample the Mississippi River plume. Surface water samples were collected using a trace metal clean towed fish and analyzed for total dissolved Fe, organic Fe complexing ligands and their associated conditional stability constants. The ligands in the river plume have conditional stability constants (log K′_FeL between 10.5 and 12.3 with an average of 11.2 and standard deviation of 0.6) very similar to ligands found in the open ocean. Comparison of high flow and low flow regimes indicates that variability in flow may be the main cause of the variability in Fe concentrations in the plume. The organic Fe complexing ligands are in greatest excess during a time of higher flow. These ligands are responsible for maintaining very high (5 nM) Fe concentrations throughout the plume. Due to complexation with these organic ligands, the concentration of Fe remains above the Fe-hydroxide solubility level until a salinity above 35 is reached where there appears to be a sink for Fe in the less productive waters. Therefore, Fe is transported a great distance from the river source and is available for biological utilization in the coastal zone.  相似文献   

Wind-induced Kuroshio intrusion into the South China Sea   总被引：14，自引：0，他引：14  

Amy Farris  Mark Wimbush 《Journal of Oceanography》1996,52(6):771-784

The Kuroshio flows north along the east coasts of the Philippines and Taiwan. Between these two land masses lies the Luzon Strait which connects the Pacific Ocean to the South China Sea. The Kuroshio usually flows north past this strait, but at times part or all of it flows west through the strait into the South China Sea forming a loop current. It has been suggested that the loop current forms when the northeast monsoon deflects the Kuroshio through the Luzon Strait. In this study, satellite-derived sea-surface temperature images are used to observe the Kuroshio in the Luzon Strait region. Together with wind data from the region, these observations indicate a loop-current development process which is largely determined by an integrated supercritical wind stress parameter. The loop current grows when a four-day average of the local wind-stress component directed to the south exceeds 0.08 Nm^–2. When this average wind-stress component drops below the critical value, the Kuroshio returns to its northward path.  相似文献   

Changes in topography and vegetation near gaps in a protective foredune     

Karl F. Nordstrom  JeanMarie Hartman  Amy L. Freestone  Mark Wong  Nancy L. Jackson 《Ocean & Coastal Management》2007,50(11-12):945-959

Data gathered on a foredune on a nourished beach reveal the relationships between topography and plant communities at gaps in the dune crest. Sand inundation at gaps allows plants in some portions of the dune to rejuvenate to earlier successional stages, while an increase in richness occurs in other portions. Ammophila breviligulata can create an initial dune ridge, colonize new areas of bare sand within the dune field, facilitate growth of other species, and provide a natural alternative to fencing in managing gaps. Foredune mobility can be considered a positive factor if beach width and dune volume provide adequate protection.  相似文献   

Nitrogen loads to New Zealand aquatic receiving environments: comparison with regulatory criteria     

Ton H. Snelder  Amy L. Whitehead  Caroline Fraser  Scott T. Larned  Marc Schallenberg 《新西兰海洋与淡水研究杂志》2020,54(3):527-550

ABSTRACT

There is concern about the deteriorating nutrient status of aquatic receiving environments in New Zealand. We estimated the amount by which current nitrogen (N) concentrations and loads exceed criteria in rivers, lakes and estuaries nationally. Criteria corresponded to national ‘bottom-line’ (i.e. minimal) environmental objectives set by government policy. Three metrics were evaluated: (1) degree of compliance describes the current TN loads in receiving environments relative to criteria; (2) catchment N status describes the acceptability of catchment N loads compared to criteria; and (3) excess load indicates the amount by which the N load exceeds the maximum allowable load (kg yr^?1). Non-compliance with N criteria was broadly distributed nationally particularly in low-elevation catchments. Catchments with unacceptable N status constituted at least 31% of New Zealand’s land area, which corresponds to at least 43% of the country’s agricultural land. The national excess load was estimated to be at least 19.1 Gg yr^?1. We are 97.5% confident that estimated excess loads exceed zero for nine of 15 regions and for the nation as a whole. The analyses provide a strategic assessment of where reductions in N emissions are required to achieve the minimal national objectives.  相似文献   

Understanding U.S. public support for domestic climate change policies     

Rachael Shwom  David Bidwell  Amy Dan  Thomas Dietz 《Global Environmental Change》2010,20(3):472-482

In the U.S., public support for federal, state and local efforts to reduce greenhouse gases (GHGs) continues to be a crucial element of the political viability of these proposals. We present a detailed analysis of the reasons given by the general public of Michigan and Virginia for supporting or rejecting a number of policies that could be implemented to meet GHG reductions. The data allow us to analyze the relationships between reasons provided by respondents, social psychological and demographic characteristics, and policy support. This analysis can provide policymakers pragmatic guidance in (1) developing tactics to engage the public that build on current concerns about climate change policies and (2) crafting and communicating policies that garner support from various segments of the public. This analysis also raises theoretical questions regarding the relationship between public discourse on environmental issues and the formation of public policy support. We suggest that future efforts to understand the U.S. dynamics of public support for climate change policies could benefit from understanding the public discursive and the reasoning processes that underlie public opinion formation.  相似文献   

Transverse structure of subtidal flow in a weakly stratified subtropical tidal inlet     

Amy F. Waterhouse  Arnoldo Valle-Levinson 《Continental Shelf Research》2010,30(3-4):281-292

The transverse structure of exchange flows and lateral flows as well as their relationship to the subtidal variability are investigated in a subtropical inlet, Ponce de Leon Inlet, Florida. Two surveys were executed during different phases of the tidal month to determine the spatial structure of subtidal exchange flows. Data from fixed moorings were used to depict the temporal variability of the spatial structure established in the surveys. The data suggested a tidally rectified pattern of net outflow in the channel and inflow over shoals with a negligible influence of streamwise baroclinic pressure gradients on the dynamics and slight modifications due to the wind. Onshore winds strengthened net inflows but weakened net outflows, rarely reversing them, while offshore winds increased net outflows and weakened net inflows. Curvature effects were found to be important in modifying secondary circulations. Slight modifications to the secondary flows were also caused by stream-normal baroclinicity during one survey. Most important, the intensity of the exchange flows was modulated by tides, with the largest exchange flows developing in response to the strongest tidal rectification of spring tides.  相似文献   

Adding our leaves: A community-wide perspective on research directions in ecohydrology     

Christina L. Tague  Shirley A. Papuga  Cynthia Gerlein-Safdi  Salli Dymond  Ryan R. Morrison  Elizabeth W. Boyer  Diego Riveros-Iregui  Elizabeth Agee  Bhavna Arora  Yannis G. Dialynas  Amy Hansen  Stefan Krause  Sylvain Kuppel  Steven P Loheide II  Stanislaus J. Schymanski  Samuel C Zipper 《水文研究》2020,34(7):1665-1673

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Radio OH observations of 9P/Tempel 1 before and after Deep Impact   总被引：1，自引：0，他引：1  

Ellen S. Howell  Amy J. Lovell  F. Peter Schloerb 《Icarus》2007,187(1):228-239

We observed 18-cm OH emission in Comet 9P/Tempel 1 before and after Deep Impact. Observations using the Arecibo Observatory 305 m telescope took place between 8 April and 9 June, 2005, followed by post-impact observations using the National Radio Astronomy Observatory 100 m Green Bank Telescope 4-12 July, 2005. The resulting spectra were analyzed with a kinematic Monte Carlo model which allows estimation of the OH production rate, neutral gas outflow velocity, and distribution of the out-gassing from the nucleus. We detected typically 24% variability from the overall OH production rate trend in the two months leading up to the impact, and no dramatic increase in OH production in the days post-impact. Generally, the coma is well-described, within uncertainties, by a symmetric model with OH production rates from 1.6 to , and mean water outflow velocity of . At these low production rates, collisional quenching is expected to occur only within 20,000 km of the nucleus. However, our best-fit average quenching radius is 64,200 ± 22,000 km in April and May.  相似文献   

Submillimeter photometry and lightcurves of Ceres and other large asteroids     

Matthew A. Chamberlain  Amy J. Lovell 《Icarus》2009,202(2):487-501

Photometry and thermal lightcurves of six large asteroids (1-Ceres, 2-Pallas, 3-Juno, 12-Victoria, 85-Io and 511-Davida) have been observed at 870 μm (345 GHz) using the MPIfR 19-Channel Bolometer of the Heinrich-Hertz Submillimeter Telescope. Only Ceres displayed a lightcurve with an amplitude (∼50%, peak to peak) that was significantly greater than the uncertainty in the observations. When thermal fluxes and brightness temperatures are corrected for heliocentric distance and albedo, there is a significant relation with the sub-solar latitude of the asteroid, or the local season of the asteroid. No such trend can be found between observations with solar phase angle. These results are evidence that most of the submillimeter thermal radiation is emitted from below the diurnal thermal wave. Comparing the observed trend with model output suggests that the submillimeter radiation from all the asteroids we observed is best modeled by surface material with low thermal inertia (<15 J m⁻² s^−0.5 K⁻¹, consistent with mid-infrared observations of large main-belt asteroids) and a refractive index closer to unity relative to densities inferred from radar experiments, implying a veneer of material over the asteroid surface with a density less than 1000 kg m⁻³. More data with better signal-to-noise and aspect coverage could improve these models and constrain physical properties of asteroid surface materials. This would also allow asteroids to be used as calibration sources with accurately known and stable, broadband fluxes at long wavelengths.  相似文献