A catalogue of caldera unrest at Taupo Volcanic Centre,New Zealand,using the Volcanic Unrest Index (VUI)     

Sally H. Potter  Bradley J. Scott  Gill E Jolly  David M. Johnston  Vince E. Neall 《Bulletin of Volcanology》2015,77(9):1-28

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Public attitudes towards flooding and property-level flood protection measures     

Seth Owusu  Grant Wright  Scott Arthur 《Natural Hazards》2015,77(3):1963-1978

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‘Bear are only the Lightning Rod’: Ongoing Acrimony in Alberta’s Grizzly Bear Recovery     

Courtney Hughes  Scott E. Nielsen 《社会与自然资源》2019,32(1):34-52

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Beringia and beyond: Papers celebrating the scientific career of Andrei Vladimirovich Sher, 1939–2008     

Scott Elias  Svetlana Kuzmina  Mary E. Edwards  Adrian M. Lister 《Quaternary Science Reviews》2011,30(17-18):2037-2038

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Do southern Appalachian Mountain summer stream temperatures respond to removal of understory rhododendron thickets?     

Scott Raulerson  C. Rhett Jackson  Nathan D. Melear  Seth E. Younger  Maura Dudley  Katherine J. Elliott 《水文研究》2020,34(14):3045-3060

Dense understory thickets of the native evergreen shrub Rhododendron maximum expanded initially following elimination of American chestnut by the chestnut blight, and later in response to loss of the eastern hemlock due to hemlock woolly adelgid invasion. Rhododendron thickets often blanket streams and their riparian zones, creating cool, low-light microclimates. To determine the effect of such understory thickets on summer stream temperatures, we removed riparian rhododendron understory on 300 m reaches of two southern Appalachian Mountain headwater streams, while leaving two 300 m reference reaches undisturbed. Overhead canopy was left intact in all four streams, but all streams were selected to have a significant component of dead or dying eastern hemlock in the overstory, creating time-varying canopy gaps throughout the reach. We continuously monitored temperatures upstream, within and downstream of treatment and reference reaches. Temperatures were monitored in all four streams in the summer before treatments were imposed (2014), and for two summers following treatment (2015, 2016). Temperatures varied significantly across and within streams prior to treatment and across years for the reference streams. After rhododendron removal, increases in summer stream temperatures were observed at some locations within the treatment reaches, but these increases did not persist downstream and varied by watershed, sensor, and year. Significant increases in daily maxima in treatment reaches ranged from 0.9 to 2.6°C. Overhead canopy provided enough shade to prevent rhododendron removal from increasing summer temperatures to levels deleterious to native cold-water fauna (average summer temperatures remained below 16°C), and local temperature effects were not persistent.  相似文献   

Water resources sustainability in a globalizing world: who uses the water?          下载免费PDF全文

Megan Konar  Tom P. Evans  Morgan Levy  Christopher A. Scott  Tara J. Troy  Charles J. Vörösmarty  Murugesu Sivapalan 《水文研究》2016,30(18):3330-3336

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Dating megafaunal extinction on the Pleistocene Darling Downs,eastern Australia: the promise and pitfalls of dating as a test of extinction hypotheses     

Gilbert J. Price  Gregory E. Webb  Jian-xin Zhao  Yue-xing Feng  Andrew S. Murray  Bernard N. Cooke  Scott A. Hocknull  Ian H. Sobbe 《Quaternary Science Reviews》2011,30(7-8):899-914

A key to understanding Late Pleistocene megafaunal extinction dynamics is knowledge of megafaunal ecological response(s) to long-term environmental perturbations. Strategically, that requires targeting fossil deposits that accumulated during glacial and interglacial intervals both before and after human arrival, with subsequent palaeoecological models underpinned by robust and reliable chronologies. Late Pleistocene vertebrate fossil localities from the Darling Downs, eastern Australia, provide stratigraphically-intact, abundant megafaunal sequences, which allows for testing of anthropogenic versus climate change megafauna extinction hypotheses. Each stratigraphic unit at site QML796, Kings Creek Catchment, was previously shown to have had similar sampling potential, and the basal units contain both small-sized taxa (e.g., land snails, frogs, bandicoots, rodents) and megafauna. Importantly, sequential faunal horizons show stepwise decrease in taxonomic diversity with the loss of some, but not all, megafauna in the geographically-small palaeocatchment. The purpose of this paper is to present the results of our intensive, multidisciplinary dating study of the deposits (>40 dates). Dating by means of accelerator mass spectrometry (AMS) ¹⁴C (targeting bone, freshwater molluscs, and charcoal) and thermal ionisation mass spectrometry U/Th (targeting teeth and freshwater molluscs) do not agree with each other and, in the case of AMS ¹⁴C dating, lack internal consistency. Scanning electron microscopy and rare earth element analyses demonstrate that the dated molluscs are diagenetically altered and contain aragonite cements that incorporated secondary young C, suggesting that such dates should be regarded as minimum ages. AMS ¹⁴C dated charcoals provide ages that occur out of stratigraphic order, and cluster in the upper chronological limits of the technique (～40–48 ka). Again, we suggest that such results should be regarded as suspicious and only minimum ages. Subsequent OSL and U/Th (teeth) dating provide complimentary results and demonstrate that the faunal sequences actually span ～120–83 ka, thus occurring beyond the AMS ¹⁴C dating window. Importantly, the dates suggest that the local decline in biological diversity was initiated ～75,000 years before the colonisation of humans on the continent. Collectively, the data are most parsimoniously consistent with a pre-human climate change model for local habitat change and megafauna extinction, but not with a nearly simultaneous extinction of megafauna as required by the human-induced blitzkrieg extinction hypothesis. This study demonstrates the problems inherent in dating deposits that lie near the chronological limits of the radiocarbon dating technique, and highlights the need to cross-check previously-dated archaeological and megafauna deposits within the timeframe of earliest human colonisation and latest megafaunal survival.  相似文献   

The influence of global sea surface temperature variability on the large-scale land surface temperature     

Nicholas L. Tyrrell  Dietmar Dommenget  Claudia Frauen  Scott Wales  Mike Rezny 《Climate Dynamics》2015,44(7-8):2159-2176

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Evaluating suspended sediment and turbidity reduction projects in a glacially conditioned catchment through dynamic regression and fluvial process-based modelling     

Kezhen Wang  Dany Davis  Scott Steinschneider 《水文研究》2021,35(9):e14351

Elevated turbidity (T_n) and suspended sediment concentrations (SSC) during and following flood events can degrade water supply quality and aquatic ecosystem integrity. Streams draining glacially conditioned mountainous terrain, such as those in the Catskill Mountains of New York State, are particularly susceptible to high levels of T_n and SSC sourced from erosional contact with glacial-related sediment. This study forwards a novel approach to evaluate the effectiveness of stream restoration best management practices (BMPs) meant to reduce stream T_n and SSC, and demonstrates the approach within the Stony Clove sub-basin of the Catskills, a water supply source for New York City. The proposed approach is designed to isolate BMP effects from natural trends in T_n and SSC caused by trends in discharge and shifts in average T_n or SSC per unit discharge (Q) following large flood events. We develop Dynamic Linear Models (DLMs) to quantify how T_n-Q and SSC-Q relationships change over time at monitoring stations upstream and downstream of BMPs within the Stony Clove and in three other sub-basins without BMPs, providing observational evidence of BMP effectiveness. A process-based model, the River Erosion Model, is then developed to simulate natural, hydrology-driven SSC-Q dynamics in the Stony Clove sub-basin (absent of BMP effects). We use DLMs to compare the modelled and observed SSC-Q dynamics and isolate the influence of the BMPs. Results suggest that observed reductions in SSC and T_n in the Stony Clove sub-basin have been driven by a combination of declining streamflow and the installed BMPs, confirming the utility of the BMPs for the monitored hydrologic conditions.  相似文献   

Some observations and characteristics of lightning ground discharges in southern Ontario     

C.L. Crozier  H.N. Herscovitch  J.W. Scott 《大气与海洋》2013,51(3):399-436

Abstract

Lightning ground flash and stroke observations were made with a single‐station gated, wideband magnetic direction‐finding system with a nominal range of 180 km located in Southern Ontario during the May‐September lightning‐active seasons of 1982 and 1983. Information was recorded on the azimuth of arrival, time, amplitude, stroke multiplicity and order, and polarity. The local climatology and seasonal statistics of lightning are analysed and summarized, and compared with standard observations of thunderstorm days and hours. Regional daily flashing rates and extremes for periods of 5 to 60 min were found to have a good empirical relationship. About 15% of the flashes had multiple strokes, generally less than 10 but with as many as 14 strokes. About 8% of the flashes were positive discharges; 3% of these were multistroke with no more than 2 strokes.

The lightning activity exhibits well defined diurnal peaks in the afternoon and at night 1–3 h before sunrise. The time interval between strokes was found to have a lognormal distribution with modal and median values of 60 and 75 ms, respectively, and no significant dependence on the order of stroke. The stroke‐to‐stroke amplitude changes within the same flash show that subsequent stroke amplitudes are often greater than the first. Subsequent strokes follow many patterns of change, the most common being an amplitude oscillating with ascending stroke order. The multistroke flash duration median values rose from about 80 ms for 2‐stroke flashes to about 650 ms for 8‐stroke flashes.

Under certain assumptions of system detection efficiency and range limits a regional ground flash density of 1.62 and 2.44 km^?2 a^?1 was estimated for the two years.  相似文献