The effect of riparian land use on transport hydraulics in agricultural headwater streams located in northeast Ohio,USA     

Kyle S. Herrman  Virginie Bouchard  Tim Granata  Anne E. Carey  Richard H. Moore 《水文研究》2010,24(1):1-12

This study examined if riparian land use (forested vs agricultural) affects hydraulic transport in headwater streams located in an agriculturally fragmented watershed. We identified paired 50‐m reaches (one reach in agricultural land use and the other in forested land use) along three headwater streams in the Upper Sugar Creek Watershed in northeast Ohio, USA (40° 51′42″N, 81° 50′29″W). Using breakthrough curves obtained by Rhodamine WT slug injections and the one‐dimensional transport with inflow and storage model (OTIS), hydraulic transport parameters were obtained for each reach on six different occasions (n = 36). Relative transient storage (A_S:A) was similar between both reach types (As: A = 0·3 ± 0·1 for both agricultural and forested reaches). Comparing values of F_med²⁰⁰ to those in the literature indicates that the effect of transient storage was moderately high in the study streams in the Upper Sugar Creek Watershed. Examining travel times revealed that overall residence time (HRT) and residence time in transient storage (T_STO) were both longer in forested reaches (forested HRT = 19·1 ± 11·5 min and T_STO = 4·0 ± 3·8 min; agricultural HRT = 9·3 ± 5·3 min and T_STO = 1·7 ± 1·4 min). We concluded that the effect of transient storage on solute transport was similar between the forested and agricultural reaches but the forested reaches had a greater potential to retain solutes as a result of longer travel times. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Mid-frequency measurements of array signal and noisecharacteristics     

Carey  W.M. Reese  J.W. Stuart  C.E. 《Oceanic Engineering, IEEE Journal of》1997,22(3):548-565

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Modal analysis of geoacoustic influences on shallow-waterpropagation     

Cederberg  R.J. Carey  W.M. Siegmann  W.L. 《Oceanic Engineering, IEEE Journal of》1997,22(2):237-244

Features observed in horizontal wavenumber spectra from low-frequency acoustic measurements taken off the New Jersey Shelf are analyzed through forward modeling using PE models. Environmental models which produce very good agreement with relative intensity data may only match wavenumbers of lower order modes. A prominent feature in contours of modal amplitude versus horizontal wavenumber and depth is the presence of double images of some higher order modes. Two possible causes of this phenomenon are examined. Range dependence in the environment can produce multiple modal images, but the magnitudes of variations required are much larger than those expected at the experiment site. The more likely cause of the double modes is shown to be a duct deep (two acoustic wavelengths) within the sediment. It produces modes with wavenumbers that are close together and with shapes that are very similar in the water column. Comparisons of model predictions with 50-Hz experimental wavenumbers and mode shapes show good agreement, except for amplitudes of some higher order modes. Predictions at 75 Hz typically require more detailed information about the sediment structure in order to accurately match all the features of higher order modes in the data  相似文献   

Stable isotopes of water reveal differences in plant – soil water relationships across northern environments     

Doerthe Tetzlaff  James Buttle  Sean K. Carey  Matthew J. Kohn  Hjalmar Laudon  James P. McNamara  Aaron Smith  Matthias Sprenger  Chris Soulsby 《水文研究》2021,35(1):e14023

We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well-known long-term study sites in northern/cold regions. These spanned a decreasing temperature gradient from Bruntland Burn (Scotland), Dorset (Canadian Shield), Dry Creek (USA), Krycklan (Sweden), to Wolf Creek (northern Canada). Xylem water was isotopically depleted compared to soil waters, most notably for deuterium. The degree to which potential soil water sources could explain the isotopic composition of xylem water was assessed quantitatively using overlapping polygons to enclose respective data sets when plotted in dual isotope space. At most sites isotopes in xylem water from angiosperms showed a strong overlap with soil water; this was not the case for gymnosperms. In most cases, xylem water composition on a given sampling day could be better explained if soil water composition was considered over longer antecedent periods spanning many months. Xylem water at most sites was usually most dissimilar to soil water in drier summer months, although sites differed in the sequence of change. Open questions remain on why a significant proportion of isotopically depleted water in plant xylem cannot be explained by soil water sources, particularly for gymnosperms. It is recommended that future research focuses on the potential for fractionation to affect water uptake at the soil-root interface, both through effects of exchange between the vapour and liquid phases of soil water and the effects of mycorrhizal interactions. Additionally, in cold regions, evaporation and diffusion of xylem water in winter may be an important process.  相似文献   

Sedimentary environments and trace fossils of the Permian Snapper Point Formation,Southern Sydney Basin     

Jan Carey 《Australian Journal of Earth Sciences》2013,60(7-8):433-458

The Lower Permian Snapper Point Formation at its type locality in the southern Sydney Basin is interpreted as a regressive sequence of a linear clastic shoreline. Lithologies, sedimentary structures, and palaeocurrent patterns suggest a prograding barrier‐beach environment. Barrier foot, bar nucleus, bar crest, and back‐bar are distinguished. Abundant trace fossils aid the recognition of minor facies. The thickness of sediments deposited in the protected inshore environment may be explained by progradation into rising relative sealevel, but rates of sealevel rise or land subsidence were ultimately exceeded by the rate of sediment supply. Up‐sequence changes in the character of the sedimentation units and biofacies may therefore reflect an evolution from a barrier profile to an open mainland beach.  相似文献   

A strategy for detecting derelict fishing gear at sea     

McElwee K  Donohue MJ  Courtney CA  Morishige C  Rivera-Vicente A 《Marine pollution bulletin》2012,65(1-3):7-15

Derelict fishing gear (DFG) is a highly persistent form of marine pollution known to cause environmental and economic damage. At-sea detection of DFG would support pelagic removal of this gear to prevent and minimize impacts on marine environments and species. In 2008, experts in marine debris, oceanography, remote sensing, and marine policy outlined a strategy to develop the capability to detect and ultimately remove DFG from the open ocean. The strategy includes three interrelated components: understanding the characteristics of the targeted DFG, indirectly detecting DFG by modeling likely locations, and directly detecting pelagic DFG using remote sensing. Together, these components aim to refine the search area, increase the likelihood of detection, and decrease mitigation response time, thereby providing guidance for removal operations. Here, we present this at-sea detection strategy, relate it to relevant extant research and technology, and identify gaps that currently prevent successful at-sea detection and removal of DFG.  相似文献   

Simulating the dispersal of tephra from the 1991 Pinatubo eruption: Implications for the formation of widespread ash layers     

Julie Fero  Steven N. Carey  John T. Merrill 《Journal of Volcanology and Geothermal Research》2009,186(1-2):120-132

PUFF and HAZMAP, two tephra dispersal models developed for volcanic hazard mitigation, are used to simulate the climatic 1991 eruption of Mt. Pinatubo. PUFF simulations indicate that the majority of ash was advected away from the source at the level of the tropopause (~ 17 km). Several eruptive pulses injected ash and SO₂ gas to higher altitudes (~ 25 km), but these pulses represent only a small fraction (~ 1%) of the total erupted material released during the simulation. Comparison with TOMS images of the SO₂ cloud after 71 and 93 h indicate that the SO₂ gas originated at an altitude of ~ 25 km near the source and descended to an altitude of ~ 22 km as the cloud moved across the Indian Ocean. HAZMAP simulations indicate that the Pinatubo tephra fall deposit in the South China Sea was formed by an eruption cloud with the majority of the ash concentrated at a height of 16–18 km. Results of this study demonstrate that the largest concentration of distal ash was transported at a level significantly below the maximum eruption column height (~ 40 km) and at a level below the calculated height of neutral buoyancy (~ 25 km). Simulations showed that distal ash transport was dominated by atmospheric circulation patterns near the regional tropopause. In contrast, the movement of the SO₂ cloud occurred at higher levels, along slightly different trajectories, and may have resulted from gas/particle segregations that took place during intrusion of the Pinatubo umbrella cloud as it moved away from source.  相似文献   

A coupled hydrology–biogeochemistry model to simulate dissolved organic carbon exports from a permafrost‐influenced catchment          下载免费PDF全文

Jason S. Lessels  Doerthe Tetzlaff  Sean K Carey  Pete Smith  Chris Soulsby 《水文研究》2015,29(26):5383-5396

We outline the development of a simple, coupled hydrology–biogeochemistry model for simulating stream discharge and dissolved organic carbon (DOC) dynamics in data sparse, permafrost‐influenced catchments with large stores of soil organic carbon. The model incorporates the influence of active layer dynamics and slope aspect on hydrological flowpaths and resulting DOC mobilization. Calibration and evaluation of the model was undertaken using observations from Granger Basin within the Wolf Creek research basin, Yukon, northern Canada. Results show that the model was able to capture the dominant hydrological response and DOC dynamics of the catchment reasonably well. Simulated DOC was highly correlated with observed DOC (r² = 0.65) for the study period. During the snowmelt period, the model adequately captured the observed dynamics, with simulations generally reflecting the timing and magnitude of the observed DOC and stream discharge. The model was less successful over the later summer period although this partly reflected a lack of DOC observations for calibration. The developed model offers a valuable framework for investigating the interactions between hydrological and DOC processes in these highly dynamic systems, where data acquisition is often very difficult. © 2015 The Authors Hydrological Processes Published by John Wiley & Sons, Ltd.  相似文献   

Anthropogenic land use is associated with N-fixing cyanobacterial dominance in lakes across the continental United States     

Jonathan P. Doubek  Cayelan C. Carey  Bradley J. Cardinale 《Aquatic Sciences - Research Across Boundaries》2015,77(4):681-694

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太阳的背面     

Bjorn Carey  胡德良 《海洋地质前沿》2006,22(11):40-40

在太阳上,看不到的那一面足以把你烤焦。太阳自转很慢,大约一个月才能转一周,这就意味着太阳另一面的每次活动会隐藏长达两周的时间。如果另一面正在形成一场巨大的磁暴,当太阳最终转到朝向地球时,磁暴就会携带大量的辐射袭击地球。这种情况在2003年发生过。当时意想不到的冲击  相似文献