Evidence of Early Metalworking in Arctic Canada     

Patricia D. Sutherland  Peter H. Thompson  Patricia A. Hunt 《Geoarchaeology》2015,30(1):74-78

This paper examines new evidence related to an early (pre‐Columbian) European presence in Arctic Canada. Artifacts from archaeological sites that had been assumed to relate to pre‐Inuit indigenous occupations of the region in the centuries around A.D. 1000 have recently been recognized as having been manufactured using European technologies. We report here on the SEM‐EDS analysis of a small stone vessel recovered from a site on Baffin Island. The interior of the vessel contains abundant traces of copper–tin alloy (bronze) as well as glass spherules similar to those associated with high‐temperature processes. These results indicate that it had been used as a crucible. This artifact may represent the earliest evidence of high‐temperature nonferrous metalworking in the New World north of Mesoamerica.  相似文献   

Overview of the Inner Front and Southeast Bering Sea Carrying Capacity Programs     

Phyllis J. Stabeno  George L. Hunt  Jr.   《Deep Sea Research Part II: Topical Studies in Oceanography》2002,49(26)

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The Kwakshua Watersheds Observatory,central coast of British Columbia,Canada     

Ian J. W. Giesbrecht  William C. Floyd  Suzanne E. Tank  Ken P. Lertzman  Brian P. V. Hunt  Maartje C. Korver  Allison A. Oliver  Ray Brunsting  Paul Sanborn  Santiago G. Gonzalez Arriola  Gordon W. Frazer  Kyra A. St. Pierre  Shawn Hateley  James McPhail  Colby Owen  Stewart Butler  Bryn Fedje  Emma Myers  Lucy Quayle  Emily Haughton  Isabelle Desmarais  Rob White  David J. Levy-Booth  Colleen T. E. Kellogg  Jennifer M. Jackson  William W. Mohn  Steven J. Hallam  Justin Del Bel Belluz 《水文研究》2021,35(6):e14198

The Kwakshua Watersheds Observatory (KWO) is an integrative watersheds observatory on the coastal margin of a rain-dominated bog-forest landscape in British Columbia (BC), Canada. Established in 2013, the goal of the KWO is to understand and model the flux of terrestrial materials from land to sea – the origins, pathways, processes and ecosystem consequences – in the context of long-term environmental change. The KWO consists of seven gauged watersheds and a network of observation sites spanning from land to sea and along drainage gradients within catchments. Time-series datasets include year-round measurements of weather, soil hydrology, streamflow, aquatic biogeochemistry, microbial ecology and nearshore oceanographic conditions. Sensor measurements are recorded every 5 min and water samples are collected approximately monthly. Additional observations are made during high-flow conditions. We used remote sensing to map watershed terrain, drainage networks, soils and terrestrial ecosystems. The watersheds range in size from 3.2 to 12.8 km², with varying catchment characteristics that influence hydrological and biogeochemical responses. Despite local variation, the overall study area is a global hotspot for yields of dissolved organic carbon, dissolved organic nitrogen and dissolved iron at the coastal margin. This observatory helps fill an important gap in the global network of observatories, in terms of spatial location (central coast of BC), climate (temperate oceanic), hydrology (very high runoff, pluvial regime), geology (igneous intrusive, glacially scoured), vegetation (bog rainforest) and soils (large stores of organic carbon).  相似文献   

Invasive species and climate change: an agronomic perspective   总被引：2，自引：0，他引：2  

Lewis H. Ziska  Dana M. Blumenthal  G. Brett Runion  E. Raymond Hunt Jr  Hilda Diaz-Soltero 《Climatic change》2011,105(1-2):13-42

In the current review we wish to draw attention to an additional aspect of invasive species and climate change, that of agricultural productivity and food security. We recognize that at present, such a review remains, in part, speculative, and more illustrative than definitive. However, recent events on the global stage, particularly in regard to the number of food riots that occurred during 2008, even at a time of record harvests, have prompted additional interest in those factors, including invasive species, which could, through climatic uncertainty, alter food production. To that end, as agricultural scientists, we wish to begin an initial evaluation of key questions related to food production and climate change including: how vulnerable is agriculture to invasive species?; are current pest management strategies sufficient to control invasive outbreaks in the future?; what are the knowledge gaps?; can we provide initial recommendations for scientists, land managers and policy makers in regard to available resources? Our overall goals are to begin a synthesis of potential impacts on productivity, to identify seminal research areas that can be addressed in future research, and to provide the scientific basis to allow agronomists and land managers to formulate mitigation and adaptation options regarding invasive species and climate change as a means to maintain food security.  相似文献   

For Whom Do We Write? Suggestions for Getting Read in the 21st Century     

Randall J. Hunt  Franklin W. Schwartz 《Ground water》2014,52(2):163-164

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Natural climatic variability and the Norse settlements in Greenland     

B. G. Hunt 《Climatic change》2009,97(3-4):389-407

A multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been used to determine whether climatic conditions approximate to those experienced by the medieval Norse settlers in Greenland could be identified. The aim of this analysis was to see whether such conditions could be replicated by the natural climatic variability in this unforced simulation, in order to counteract claims that the current observed global warming is merely another example of this type of climatic regime. This view has been expressed in the media in an attempt to refute the existence of a CO₂-induced global warming. A 291-year period of above-average temperature followed by a 41-year cooler period were identified in one millennium of the simulation, and subsequently used as an analogue of conditions representative of the time of the Norse settlements. Considerable interannual variability existed in both these periods, but with noticeable positive and negative surface temperature anomalies in the warm and cold periods respectively. Thus the warm period was not a time of uniform benign conditions. Above-average precipitation was also associated with the warm period, and these climatic conditions would have enhanced pasture growth and hay production (the only crop the Norse produced) thereby sustaining the livelihood of the Norse Greenlanders. The climatic conditions associated with the cold period in the model were probably sufficient to limit the survival prospects of the settlers, especially when other, probably more critical, deleterious factors are taken into account. The temperature anomalies replicated in the simulation are similar to the limited proxy data, but may be smaller in magnitude: nevertheless they appear to be sufficiently large to have affected the viability of the Norse Greenlanders. After considering possible climatic mechanisms that could have contributed to these warm and cold periods it was concluded that they are simply a consequence of stochastic influences generated by nonlinear processes in the simulation. Thus this simulation provides no support for the contention that the current global warming is a manifestation of conditions prevailing during the Norse settlements in Greenland.  相似文献   

Stochastic control of Indian megadroughts and megafloods     

B. G. Hunt 《Climate Dynamics》2012,39(7-8):1801-1821

A multi-millennial run of the CSIRO Mark2 coupled climatic model has been used to investigate megadroughts and megafloods during the Indian summer monsoon (June–September). These extreme events were defined as having rainfall anomalies at least two standard deviations from normal. More than ten megafloods and more than twenty megadroughts, so-defined, were found to occur in a 5,000-year period of the simulation. The simulation replicated most of the major features of the observed summer monsoon, but a comparison of observed and simulated probability density functions suggests that the limited observed rainfall time series to date does not adequately sample the possible range of Indian monsoonal rainfall. An investigation of causal mechanisms of Indian rainfall variability reproduced the observed negative correlation with ENSO events, but it was found that neither extreme ENSO events or extremes of a range of other climatic phenomena coincided with the simulated, extreme megadroughts and megafloods. This disconnect between these events is succinctly illustrated with examples related to ENSO events in particular. Autoregressive and FFT analysis of observed and simulated Indian summer monsoon rainfall time series revealed them to consist of white noise. Since these time series therefore consist of random outcomes, it is apparent that these Indian megadroughts and megafloods are the consequence of stochastic influences. Thus, it is concluded that the interannual variability of Indian summer monsoonal rainfall cannot be predicted in general, nor can megadroughts and megafloods in particular.  相似文献   

Pathogen transport in groundwater systems: contrasts with traditional solute transport     

Randall J. Hunt  William P. Johnson 《Hydrogeology Journal》2017,25(4):921-930

Water quality affects many aspects of water availability, from precluding use to societal perceptions of fit-for-purpose. Pathogen source and transport processes are drivers of water quality because they have been responsible for numerous outbreaks resulting in large economic losses due to illness and, in some cases, loss of life. Outbreaks result from very small exposure (e.g., less than 20 viruses) from very strong sources (e.g., trillions of viruses shed by a single infected individual). Thus, unlike solute contaminants, an acute exposure to a very small amount of contaminated water can cause immediate adverse health effects. Similarly, pathogens are larger than solutes. Thus, interactions with surfaces and settling become important even as processes important for solutes such as diffusion become less important. These differences are articulated in “Colloid Filtration Theory”, a separate branch of pore-scale transport. Consequently, understanding pathogen processes requires changes in how groundwater systems are typically characterized, where the focus is on the leading edges of plumes and preferential flow paths, even if such features move only a very small fraction of the aquifer flow. Moreover, the relatively short survival times of pathogens in the subsurface require greater attention to very fast (<10 year) flow paths. By better understanding the differences between pathogen and solute transport mechanisms discussed here, a more encompassing view of water quality and source water protection is attained. With this more holistic view and theoretical understanding, better evaluations can be made regarding drinking water vulnerability and the relation between groundwater and human health.  相似文献   

Report of the IAU/IAG/COSPAR working group on cartographic coordinates and rotational elements of the planets and satellites: 1988     

M. E. Davies  V. K. Abalakin  M. Bursa  G. E. Hunt  J. H. Lieske  B. morando  R. H. Rapp  P. K. Seidelmann  A. T. Sinclair  Y. S. Tjuflin 《Celestial Mechanics and Dynamical Astronomy》1989,46(2):187-204

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Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation     

Hunt RJ  Steuer JJ  Mansor MT  Bullen TD 《Ground water》2001,39(5):702-712

Recharge areas of spring systems can be hard to identify, but they can be critically important for protection of a spring resource. A recharge area for a spring complex in southern Wisconsin was delineated using a variety of complementary techniques. A telescopic mesh refinement (TMR) model was constructed from an existing regional-scale ground water flow model. This TMR model was formally optimized using parameter estimation techniques; the optimized "best fit" to measured heads and fluxes was obtained by using a horizontal hydraulic conductivity 200% larger than the original regional model for the upper bedrock aquifer and 80% smaller for the lower bedrock aquifer. The uncertainty in hydraulic conductivity was formally considered using a stochastic Monte Carlo approach. Two-hundred model runs used uniformly distributed, randomly sampled, horizontal hydraulic conductivity values within the range given by the TMR optimized values and the previously constructed regional model. A probability distribution of particles captured by the spring, or a "probabilistic capture zone," was calculated from the realistic Monte Carlo results (136 runs of 200). In addition to portions of the local surface watershed, the capture zone encompassed areas outside of the watershed--demonstrating that the ground watershed and surface watershed do not coincide. Analysis of water collected from the site identified relatively large contrasts in chemistry, even for springs within 15 m of one another. The differences showed a distinct gradation from Ordovician-carbonate-dominated water in western spring vents to Cambrian-sandstone-influenced water in eastern spring vents. The difference in chemistry was attributed to distinctive bedrock geology as demonstrated by overlaying the capture zone derived from numerical modeling over a bedrock geology map for the area. This finding gives additional confidence to the capture zone calculated by modeling.  相似文献