bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling and analysis of the impact of irrigation on local arid climate over northwest China
Authors: Wen Lijuan , Jin Jiming 
Published: April 2011

AbstractThis study focuses on how irrigation processes affect local climate over arid areas. The chosen study area is northwest China, a typical arid region where three dominant land‐use types are irrigated cropland, grassland, and desert. Observational analysis indicates that the highest precipitation, the coolest surface temperatures, and the slowest warming trend are seen over irrigated cropland from 1979 to 2005. The single column atmospheric model (SCAM), developed by the National Center for Atmospheric Research (NCAR), was used to investigate and better understand the differences in long‐term climate conditions and change over the above three land‐use types. The results indicate that local climate conditions are predominantly controlled by large‐scale forcing in this arid region and that local land surface forcing related to vegetation cover change and irrigation processes also has a significant impact. This study strongly suggests that a realistic climate forecast for this region can be achieved only with both accurate large‐scale and local climate forcing. The irrigated cropland of the region generates stronger evaporation that cools the surface and slows the warming trend more than does the evaporation from the natural grassland and desert. Stronger evaporation also significantly increases precipitation, potentially alleviating the stress of irrigation demands in arid regions. A series of sensitivity SCAM simulations indicate that a drier and warmer climate occurs with decreasing vegetation cover in the irrigated cropland region. Copyright © 2011 John Wiley & Sons, Ltd.
Internal structure and hydrological functions of an alpine proglacial moraine
Authors: Langston Gregory , Bentley Laurence R. , Hayashi Masaki , McClymont Alastair , Pidlisecky Adam 
Published: April 2011

AbstractUnderstanding groundwater processes in alpine watersheds is critical to understand the timing of water release and late‐season stream flow for both headwater and downstream environments. Moraines and talus features can play an important role in groundwater flow and storage processes in alpine watersheds, but neither process is well understood for these features. We examined the complex hydrogeological environment of a partially ice‐cored moraine in the Lake O'Hara watershed in the Canadian Rockies. Electrical resistivity imaging (ERI) and seismic refraction tomography delineated regions of buried ice and frozen and unfrozen moraine material. Seismic refraction data also clearly indicated the depth to bedrock, which varied primarily due to the thickness of the overlying moraine material. Water levels in a lake and several tarns on the moraine responded differently to inputs of rain, snowmelt, and glacier melt, indicating the different degree of hydrological connectivity of these features to the groundwater flow system in the moraine. Such differences reflect the effects of bedrock topography and the location and geometry of buried ice. Ground‐penetrating radar images and ERI indicated regions of perched groundwater and focused infiltration. The location of these regions appears to be controlled by buried ice. All geophysical and hydrological data suggest that a relatively thin (<5 m) layer of saturated sediments and/or fractured bedrock likely provides a major flow system within the moraine. Copyright © 2011 John Wiley & Sons, Ltd.
Assessment on variability of extreme climate events for the Upper Thames River basin in Canada
Authors: Eum Hyung‐Il , Simonovic Slobodan P. 
Published: April 2011

AbstractClimate change may affect magnitude and frequency of regional extreme events with possibility of serious impacts on the existing infrastructure systems. This study investigates how the current spatial and temporal variations of extreme events are affected by climate change in the Upper Thames River basin, Ontario, Canada. A weather generator model is implemented to obtain daily time series of three climate variables for two future climate scenarios. The daily time series are disaggregated into hourly to capture characteristics of intense and rapidly changing storms. The maximum annual precipitation events for five short durations, 6‐, 12‐, 24‐, 48‐, and 72‐h durations, at each station are extracted from the generated hourly data. The frequency and seasonality analyses are conducted to investigate the temporal and spatial variability of extreme precipitation events corresponding to each duration. In addition, this study investigates the impacts of increase in temperature using reliability, resilience, and vulnerability. The results indicate that the extreme precipitation events under climate change will occur earlier than in the past. In addition, episodes of extremely high temperature may last longer up to 19·7% than under the no‐change climate scenario. This study points out that the revision of the design storms (e.g. 100‐ or 250‐year return period) is warranted for the west and the south east region of the basin. Copyright © 2011 John Wiley & Sons, Ltd.
The influence of dam and lakes on the Yangtze River streamflow: long‐range correlation and complexity analyses
Authors: Zhang Qiang , Zhou Yu , Singh Vijay P. , Chen Xiaohong 
Published: April 2011

AbstractEmploying long‐range correlation, complexity features and clustering, this study investigated the influence of dam and lake‐river systems on the Yangtze River flow. The impact of the Gezhouba Dam and the lake systems on streamflow was evaluated by analysing daily streamflow records at the Cuntan, the Yichang and the Datong station. Results indicated no evident influence of the Gezhouba Dam on streamflow changes. Distinct differences in scaling behaviour, long‐range correlation and clustering of streamflow at the Datong station when compared with those at the Cuntan and Yichang stations undoubtedly showed the influence of water storage and the buffering effect of the lake systems between the Datong station and other two hydrological stations on streamflow in the lower Yangtze River basin. Decreased regularity, enhanced long‐range correlation and increased clustering of streamflow in the lower Yangtze River basin due to the effect of water storage of the lake systems were corroborated. Copyright © 2011 John Wiley & Sons, Ltd.
Quantification of incoming all‐wave radiation in discontinuous forest canopies with application to snowmelt prediction
Authors: Lawler Robert R. , Link Timothy E. 
Published: April 2011

AbstractSnowmelt dynamics in forested areas are largely driven by net radiation, which is controlled by solar elevation angle and spatial variations in canopy structure. Understanding of the spatiotemporal radiative regimes in discontinuous forests during the snow season is limited. To improve understanding of radiation dynamics in discontinuous forests, a theoretical, spatially explicit, all‐wave irradiance model was developed. The model was tested using detailed measurements collected with radiometer arrays consisting of 16 pyranometers and 14 pyrgeometers installed in a small forest canopy gap. The model was used to simulate incoming radiation over the snow season at mid‐latitude (47°N), level forest canopy gaps with diameters ranging from one to six times the surrounding tree heights (H). Theoretical results indicate that radiative regimes in small canopy gaps may be distinctly different from continuous open areas and closed‐canopy forests, especially at low solar elevation angles. At low sun angles, spatial radiative minima can occur in gaps due to low incoming shortwave radiation caused by canopy shading, coupled with minimal longwave radiation enhancement from surrounding forests. At 47°N latitude on 1 February, simulated incoming all‐wave radiation in canopy gaps was less than both open and forested areas over 100 to 33% of north‐south transects ranging from 25 to 150 m in 1H to 6H gaps, respectively. By 1 May, the zone of radiative minima in 1H to 6H gaps ranged from 44 to 8%, respectively. The outcome of this work is an enhanced understanding of radiation variability in discontinuous forest canopies during the snow season. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of a thin veneer of low‐hydraulic‐conductivity sediment on modelled exchange between river water and groundwater in response to induced infiltration
Authors: Rosenberry Donald O. , Healy Richard W. 
Published: April 2011

AbstractA thin layer of fine‐grained sediment commonly is deposited at the sediment–water interface of streams and rivers during low‐flow conditions, and may hinder exchange at the sediment–water interface similar to that observed at many riverbank‐filtration (RBF) sites. Results from a numerical groundwater‐flow model indicate that a low‐permeability veneer reduces the contribution of river water to a pumping well in a riparian aquifer to various degrees, depending on simulated hydraulic gradients, hydrogeological properties, and pumping conditions. Seepage of river water is reduced by 5–10% when a 2‐cm thick, low‐permeability veneer is present on the bed surface. Increasing thickness of the low‐permeability layer to 0·1 m has little effect on distribution of seepage or percentage contribution from the river to the pumping well. A three‐orders‐of‐magnitude reduction in hydraulic conductivity of the veneer is required to reduce seepage from the river to the extent typically associated with clogging at RBF sites. This degree of reduction is much larger than field‐measured values that were on the order of a factor of 20–25. Over 90% of seepage occurs within 12 m of the shoreline closest to the pumping well for most simulations. Virtually no seepage occurs through the thalweg near the shoreline opposite the pumping well, although no low‐permeability sediment was simulated for the thalweg. These results are relevant to natural settings that favour formation of a substantial, low‐permeability sediment veneer, as well as central‐pivot irrigation systems, and municipal water supplies where river seepage is induced via pumping wells. Published in 2011 by John Wiley & Sons, Ltd.
Sensitivity of the snowcover energetics in a mountain basin to variations in climate
Authors: Reba Michele L. , Marks Danny , Winstral Adam , Link Timothy E. , Kumar Mukesh 
Published: April 2011

AbstractSnow is an important natural reservoir that holds water on the landscape for release later in the season in western North America and other portions of the world. As air temperature increases with global climate change, the character of the generally established seasonal snowcover will be affected. To study the specific response to variable climate, a carefully collected and processed meteorological data set for the 1984–2008 water years (WYs) was assembled for a snow‐dominated headwater mountain catchment. The data were used to force a physically based, distributed energy balance snow model to simulate patterns of snow deposition and melt over the catchment for the 25‐year period. This period covers both the highest (1984) and lowest (1992) snow seasons on record and exhibits extreme inter‐annual variability. This unique forcing data set captured meteorological conditions that resulted in the range of variability in snowcover accumulation, timing of ablation, and the timing and amount of surface water input (SWI), and discharge during the 25‐year study period. SWI is the amount of liquid water delivered to the soil surface from melting snow or from rain that passes through the snowcover or falls directly on the soil. Warm winters, characterized by early‐ and mid‐winter rain, triggered earlier inputs from SWI and response in discharge than cool winters. Cool conditions prolonged the generation of SWI and streamflow out of the basin. Very wet conditions that were warm passed 50% of the SWI 27 days earlier and passed 50% of the discharge 15 days earlier, when compared to very wet conditions that were cool. Warmer conditions produced less snow water equivalent, shortened the melt season, and would be expected to extend the summer drought. Copyright © 2011 John Wiley & Sons, Ltd.
Modelling catchment‐scale shallow landslide occurrence and sediment yield as a function of rainfall return period
Authors: Bovolo C. I. , Bathurst J. C. 
Published: April 2011

AbstractA model‐based method is proposed for improving upon existing threshold relationships which define the rainfall conditions for triggering shallow landslides but do not allow the magnitude of landsliding (i.e. the number of landslides) to be determined. The SHETRAN catchment‐scale shallow landslide model is used to quantify the magnitude of landsliding as a function of rainfall return period, for focus sites of 180 and 45 km2 in the Italian Southern Alps and the central Spanish Pyrenees. Rainfall events with intensities of different return period are generated for a range of durations (1‐day to 5‐day) and applied to the model to give the number of landslides triggered and the resulting sediment yield for each event. For a given event duration, simulated numbers of landslides become progressively less sensitive to return period as return period increases. Similarly, for an event of given return period, landslide magnitude becomes less sensitive to event duration as duration increases. The temporal distribution of rainfall within an event is shown to have a significant impact on the number of landslides and the timing of their occurrence. The contribution of shallow landsliding to catchment sediment yield is similarly quantified as a function of the rainfall characteristics. Rainfall intensity–duration curves are presented which define different levels of landsliding magnitude and which advance our predictive capability beyond, but are generally consistent with, published threshold curves. The magnitude curves are relevant to the development of guidelines for landslide hazard assessment and forecasting. Copyright © 2011 John Wiley & Sons, Ltd.
Bioaccumulation data from laboratory and field studies: Are they comparable?
Authors: Burkhard Lawrence P , Cowan-Ellsberry Christina , Embry Michelle R , Hoke Robert A , Kidd Karen A 
Published: April 2011

Abstract
Once they are released into the environment, a number of chemicals are known to bioaccumulate in organisms, sometimes to concentrations that may threaten the individual or their predators. However, use of physical or chemical properties or results from laboratory bioaccumulation tests to predict concentrations sometimes found in wild organisms remains a challenge. How well laboratory studies and field measurements agree or disagree, and the cause of any discrepancies, is a subject of great interest and discussion from both a scientific and a regulatory perspective. A workshop sponsored by the ILSI Health and Environmental Sciences Institute, US Environmental Protection Agency, and the Society of Environmental Toxicology and Chemistry assembled scientists from academia, industry, and government to compare and contrast laboratory and field bioaccumulation data. The results of this workshop are summarized in a series of 5 articles published in this issue of Integrated Environmental Assessment and Management. The articles describe: 1) a weight-of-evidence approach that uses fugacity ratios to bring field measurements into the assessment of biomagnification potential for legacy chemicals; 2) a detailed comparison between laboratory and field data for the most commonly measured bioaccumulation endpoint, the biota–sediment accumulation factor; 3) a study that identifies and quantifies the differences between laboratory and field metrics of bioaccumulation for aquatic and terrestrial organisms; and 4) 2 reports on trophic magnification factors: the 1st addresses how trophic magnification factors are determined and interpreted and the 2nd describes how they could be used in regulatory assessments. Collectively, these articles present the workshop participants' current understanding and assessment of bioaccumulation science and make a number of recommendations on how to improve the collection and interpretation of bioaccumulation data. Integr Environ Assess Manag 2012;8:13–16. © 2011 SETAC
Xplicit, a novel approach in probabilistic spatiotemporally explicit exposure and risk assessment for plant protection products
Authors: Schad Thorsten , Schulz Ralf 
Published: April 2011

Abstract
The quantification of risk (the likelihood and extent of adverse effects) is a prerequisite in regulatory decision making for plant protection products and is the goal of the Xplicit project. In its present development stage, realism is increased in the exposure assessment (EA), first by using real-world data on, e.g., landscape factors affecting exposure, and second, by taking the variability of key factors into account. Spatial and temporal variability is explicitly addressed. Scale dependencies are taken into account, which allows for risk quantification at different scales, for example, at landscape scale, an overall picture of the potential exposure of nontarget organisms can be derived (e.g., for all off-crop habitats in a given landscape); at local scale, exposure might be relevant to assess recovery and recolonization potential; intermediate scales might best refer to population level and hence might be relevant for risk management decisions (e.g., individual off-crop habitats). The Xplicit approach is designed to comply with a central paradigm of probabilistic approaches, namely, that each individual case that is derived from the variability functions employed should represent a potential real-world case. This is mainly achieved by operating in a spatiotemporally explicit fashion. Landscape factors affecting the local exposure of habitats of nontarget species (i.e., receptors) are derived from geodatabases. Variability in time is resolved by operating at discrete time steps, with the probability of events (e.g., application) or conditions (e.g., wind conditions) defined in probability density functions (PDFs). The propagation of variability of parameters into variability of exposure and risk is done using a Monte Carlo approach. Among the outcomes are expectancy values on the realistic worst-case exposure (predicted environmental concentration [PEC]), the probability p that the PEC exceeds the ecologically acceptable concentration (EAC) for a given fraction of habitats, and risk curves. The outcome can be calculated at any ecologically meaningful organization level of receptors. An example application of Xplicit is shown for a hypothetical risk assessment for nontarget arthropods (NTAs), demonstrating how the risk quantification can be improved compared with the standard deterministic approach. Integr Environ Assess Manag 2011;7:612–623. © 2011 SETAC
Development and evaluation of a dynamic model that projects population biomarkers of methylmercury exposure from local fish consumption
Authors: Chan Caroline , Heinbokel John F , Myers John A , Jacobs Robert R. 
Published: April 2011

Abstract
A dynamic model was developed to project Hg concentrations in common biomarkers of exposure in response to changes in Hg concentrations in predatory fish from local waters. The model predicts biomarkers in susceptible populations for intake rates representing the mean, 90th, 95th, and 99th percentiles of populations of interest. The biomarkers the model calculates are blood methylmercury, total hair Hg, and fetal blood methylmercury. Decision makers can use the model to determine the degree of reduction in fish tissue Hg levels necessary to protect the health of susceptible populations. Biomarker output was calibrated with literature sources. Output was then compared to additional literature sources to evaluate model function. Projected biomarkers were not different from literature sources. The model can be used as a tool to understand the impact of local fish consumption on susceptible populations. Integr Environ Assess Manag 2011;7:624–635. © 2011 SETAC
Use of trophic magnification factors and related measures to characterize bioaccumulation potential of chemicals
Authors: Conder Jason M , Gobas Frank A P C , Borgå Katrine , Muir Derek C G , Powell David E 
Published: April 2011

Abstract
Recent technical workgroups have concluded that trophic magnification factors (TMFs) are useful in characterizing the bioaccumulation potential of a chemical, because TMFs provide a holistic measure of biomagnification in food webs. The objectives of this article are to provide a critical analysis of the application of TMFs for regulatory screening for bioaccumulation potential, and to discuss alternative methods for supplementing TMFs and assessing biomagnification in cases where insufficient data are available to determine TMFs. The general scientific consensus is that chemicals are considered bioaccumulative if they exhibit a TMF &gt; 1. However, comparison of study-derived TMF estimates to this threshold value should be based on statistical analyses such that variability is quantified and false positive and false negative errors in classification of bioaccumulation potential are minimized. An example regulatory decision-making framework is presented to illustrate the use of statistical power analyses to minimize assessment errors. Suggestions for considering TMF study designs and TMFs obtained from multiple studies are also provided. Alternative bioaccumulation metrics are reviewed for augmenting TMFs and for substituting in situations in which field data for deriving TMFs are unavailable. Field-derived, trophic level-normalized biomagnification factors (BMFTLs), biota–sediment accumulation factors (BSAFTLs), and bioaccumulation factors (BAFTLs) are recommended if data are available, because these measures are most closely related to the biomagnification processes characterized by TMFs. Field- and laboratory-derived BAFs and bioconcentration factors are generally less accurate in predicting biomagnification. However, bioconcentration factors and BAFs remain useful for characterizing bioaccumulation as a result of the transfer of chemicals from abiotic environmental compartments to lower trophic levels. Modeling that incorporates available laboratory and field data should also be considered for augmenting assessments of bioaccumulation potential. Modeling can provide a TMF-focused assessment for new or unreleased chemicals in the absence of field data by estimating TMF values and theoretical relationships between physical-chemical properties and TMF values (quantitative structure–activity relationships). An illustration of the use of physicochemical properties for estimating TMFs is provided. Overall, TMFs provide valuable information regarding bioaccumulation potential and should be incorporated into regulatory decision making following the suggestions outlined in this article. Integr Environ Assess Manag 2012;8:?–?. © 2011 SETAC