Lithospheric structure north of Scotland—II. Poisson's ratios and waveform modelling     

Claire Price  Joanna Morgan 《Geophysical Journal International》2000,142(3):737-754

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Snow hydrology of a constructed watershed in the Athabasca oil sands region,Alberta, Canada          下载免费PDF全文

Scott J. Ketcheson  Jonathan S. Price 《水文研究》2016,30(14):2546-2561

Wetlands are now being integrated into oil sands mining landscape closure design plans. These wetland ecosystems will be constructed within a regional sub‐humid climate where snowfall represents ~25% of annual precipitation. However, few studies focus on the distribution of snow and, hence, the storage of winter precipitation in reclaimed oil sands landscapes. In this study, the distribution, ablation and fate of snowmelt waters are quantified within a constructed watershed in a post‐mining oil sands environment. Basin‐averaged peak SWE was 106 mm, with no significant difference between reclaimed slopes with vegetation and those that were sparsely vegetated or bare. Snow depth was greatest and more variable near the toe of slopes and became progressively shallower towards the crest. Snow ablation started first on the vegetated slope, which also exhibited the maximum observed ablation rates. This enhanced melt was attributed to increased absorption of short‐wave radiation by vegetation stems and branches. Recharge to reclaimed slopes and a constructed aquifer during the snowmelt period was minimal, as the presence of ground frost minimized infiltration. Accordingly, substantial surface run‐off was observed from all reclaimed slopes, despite being designed to reduce run‐off and increase water storage. This could result in increased flashiness of downstream watercourses during the spring freshet that receive run‐off from post‐mining landscapes where large reclaimed slopes are prolific. Run‐off ratios for the reclaimed slopes were between 0.7 and 0.9. Thus, it is essential to consider snow dynamics when designing landscape‐scale constructed ecosystems. This research demonstrates that the snowmelt period hydrology within reclaimed landscapes is fundamentally different from that reported for natural settings and represents one of the first studies on snow dynamics in constructed watershed systems in the post‐mined oil sands landscape. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

The role of recharge and evapotranspiration as hydraulic drivers of ion concentrations in shallow groundwater on Everglades tree islands,Florida (USA)          下载免费PDF全文

Pamela L. Sullivan  René M. Price  Fernando Miralles‐Wilhelm  Mike S. Ross  Leonard J. Scinto  Thomas W. Dreschel  Fred H. Sklar  Eric Cline 《水文研究》2014,28(2):293-304

Recently, evapotranspiration has been hypothesized to promote the secondary formation of calcium carbonate year‐round on tree islands in the Everglades by influencing groundwater ions concentrations. However, the role of recharge and evapotranspiration as drivers of shallow groundwater ion accumulation has not been investigated. The goal of this study is to develop a hydrologic model that predicts the chloride concentrations of shallow tree island groundwater and to determine the influence of overlying biomass and underlying geologic material on these concentrations. Groundwater and surface water levels and chloride concentrations were monitored on eight constructed tree islands at the Loxahatchee Impoundment Landscape Assessment (LILA) from 2007 to 2010. The tree islands at LILA were constructed predominately of peat, or of peat and limestone, and were planted with saplings of native tree species in 2006 and 2007. The model predicted low shallow groundwater chloride concentrations when inputs of regional groundwater and evapotranspiration‐to‐recharge rates were elevated, while low evapotranspiration‐to‐recharge rates resulted in a substantial increase of the chloride concentrations of the shallow groundwater. Modeling results indicated that evapotranspiration typically exceeded recharge on the older tree islands and those with a limestone lithology, which resulted in greater inputs of regional groundwater. A sensitivity analysis indicated the shallow groundwater chloride concentrations were most sensitive to alterations in specific yield during the wet season and hydraulic conductivity in the dry season. In conclusion, the inputs of rainfall, underlying hydrologic properties of tree islands sediments and forest structure may explain the variation in ion concentration seen across Everglades tree islands. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Radiation Fog. Part I: Observations of Stability and Drop Size Distributions   总被引：1，自引：1，他引：0  

Jeremy Price 《Boundary-Layer Meteorology》2011,139(2):167-191

Data from several cases of radiation fog occurring at the Met Office field site at Cardington, Bedfordshire, UK have been analyzed with a view to elucidating the typical evolution in its static stability from formation to dissipation. Typically the early stages of radiation fog are characterized by a stable thermal profile and a relatively shallow depth. However, when the fog reached approximately 100 m depth it was observed to become optically thick (to longwave radiation), with a subsequent change over several hours to a saturated adiabatic stability profile. At this time turbulence levels were seen to increase significantly. The mechanisms involved appear to be radiative cooling from fog top and a positive heat flux to the atmosphere from the soil. The importance of this change in stability for numerical modelling of fog episodes is discussed. Several case studies are made to gain some insight into how common this transition is. Droplet spectra were measured at 2-m height for many of the cases considered, and their evolution is discussed. It is found that distributions fall into an initial phase with small drop sizes (approximately ≤ 10 μm diameter) and concentration, and a mature phase with the appearance of much larger drop sizes with a mean diameter of approximately 15−20 μm. It is found that the appearance of the mature phase does not coincide with the change in stability from stable to saturated adiabatic, but there is some evidence that once a saturated adiabatic profile is established, the droplet spectra variations are significantly less than for the stable period. The observed evolution of these spectra brings into question the suitability of microphysical schemes that assume constant spectral shape, drop diameter, and number density.  相似文献   

Sea level rise and South Florida coastal forests   总被引：1，自引：0，他引：1  

Amartya K. Saha  Sonali Saha  Jimi Sadle  Jiang Jiang  Michael S. Ross  Ren�� M. Price  Leonel S. L. O. Sternberg  Kristie S. Wendelberger 《Climatic change》2011,107(1-2):81-108

Coastal ecosystems lie at the forefront of sea level rise. We posit that before the onset of actual inundation, sea level rise will influence the species composition of coastal hardwood hammocks and buttonwood (Conocarpus erectus L.) forests of the Everglades National Park based on tolerance to drought and salinity. Precipitation is the major water source in coastal hammocks and is stored in the soil vadose zone, but vadose water will diminish with the rising water table as a consequence of sea level rise, thereby subjecting plants to salt water stress. A model is used to demonstrate that the constraining effect of salinity on transpiration limits the distribution of freshwater-dependent communities. Field data collected in hardwood hammocks and coastal buttonwood forests over 11 years show that halophytes have replaced glycophytes. We establish that sea level rise threatens 21 rare coastal species in Everglades National Park and estimate the relative risk to each species using basic life history and population traits. We review salinity conditions in the estuarine region over 1999?C2009 and associate wide variability in the extent of the annual seawater intrusion to variation in freshwater inflows and precipitation. We also examine species composition in coastal and inland hammocks in connection with distance from the coast, depth to water table, and groundwater salinity. Though this study focuses on coastal forests and rare species of South Florida, it has implications for coastal forests threatened by saltwater intrusion across the globe.  相似文献   

Using Lightning Data to Better Understand and Predict Flash Floods in the Mediterranean     

C. Price  Y. Yair  A. Mugnai  K. Lagouvardos  M. C. Llasat  S. Michaelides  U. Dayan  S. Dietrich  F. Di Paola  E. Galanti  L. Garrote  N. Harats  D. Katsanos  M. Kohn  V. Kotroni  M. Llasat-Botija  B. Lynn  L. Mediero  E. Morin  K. Nicolaides  S. Rozalis  K. Savvidou  B. Ziv 《Surveys in Geophysics》2011,32(6):733-751

One of the costliest natural hazards around the globe is flash floods, resulting from localized intense convective precipitation over short periods of time. Since intense convective rainfall (especially over the continents) is well correlated with lightning activity in these storms, a European Union FP6 FLASH project was realized from 2006 to 2010, focusing on using lightning observations to better understand and predict convective storms that result in flash floods. As part of the project, 23 case studies of flash floods in the Mediterranean region were examined. For the analysis of these storms, lightning data were used together with rainfall estimates in order to understand the storms?? development and electrification processes. In addition, these case studies were simulated using mesoscale meteorological models to better understand the local and synoptic conditions leading to such intense and damaging storms. As part of this project, tools for short-term predictions (nowcasts) of intense convection across the Mediterranean and Europe, and long-term forecasts (a few days) of the likelihood of intense convection, were developed and employed. The project also focused on educational outreach through a special Web site http://flashproject.org supplying real-time lightning observations, real-time experimental nowcasts, medium-range weather forecasts and educational materials. While flash floods and intense thunderstorms cannot be prevented, long-range regional lightning networks can supply valuable data, in real time, for warning the public, end-users and stakeholders of imminent intense rainfall and possible flash floods.  相似文献   

Paleogene carbon isotope excursions in the Bunkers Hill borehole: Hampshire Basin, UK     

Emma Hodgson  Stephen T. Grimes  Gregory D. Price  Meriel E.J. Fitzpatrick  Malcolm B. Hart  Melanie J. Leng 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(3):460-471

This study demonstrates that the Bunkers Hill borehole, which is located within the Hampshire Basin, contains a carbon isotope excursion (CIE) in the Upnor Formation followed by a positive recovery from another CIE within the overlying Reading Formation. This study has also shown that the CIE in the Upnor Formation predates the Paleocene/Eocene Thermal Maximum (PETM), while the carbon isotope recovery at the base of the Reading Formation is most likely related to it. The positive carbon isotope trend, before a return to more negative values, seen throughout the majority of the Reading Formation can also be seen in coeval deposits in the Jubilee 404T borehole in the London Basin and in the Tienen Formation in the Doel and Kallo boreholes from the Belgium Basin. This indicates that this post-PETM carbon isotope signal may, therefore, be regional if not global in nature.  相似文献   

Solid-phase considerations for the environmental fate of nitrobenzene and triazine munition constituents in soil     

Mark A. Chappell  Cynthia L. Price  Lesley F. Miller 《Applied Geochemistry》2011

This paper focuses on the chemistry of DoD-relevant organic contaminants in soil. Most of the work presented here is based on the author’s experience with the environmental fate of the munition constituents, TNT and RDX, for DoD related issues. The principles and challenges of understanding the transport of nitrobenzene and triazine compounds in the environment are captured. In this work, disparities in the current scientific literature with respect to the construction of sorption experiments are discussed, in terms of soil sample handling, dispersion state of the soil, and sorption hysteresis/equilibrium. Here is discussed the concept of environmentally formulated compounds and its implications toward reduced accuracy of predicting the environmental fate of munition constituents. Also, further research linking simple but oft-forgotten basic concepts of soil fertility to the transport and environmental fate of munition constituents are discussed.  相似文献   

An integrated methodology for salt damage assessment and remediation: the case of San Jerónimo Monastery (Granada, Spain)     

E. Ruiz-Agudo  B. Lubelli  A. Sawdy  R. van Hees  C. Price  C. Rodriguez-Navarro 《Environmental Earth Sciences》2011,63(7-8):1475-1486

San Jerónimo Monastery (Granada, Spain) was selected as a case study for the investigation of the effect of indoor environmental conditions on salt weathering and for on-site testing of a remediation treatment using crystallization inhibitors on account of the extreme salt damage affecting both the building stone, a biomicritic limestone, calcarenite and wall paintings. A methodology combining several analysis techniques, phenomenological observations, salt and moisture analysis, environmental monitoring and thermodynamic simulations, was adopted in order to study the salt damage problems affecting this building. Within the collected samples, the majority of salts were found to be magnesium sulphate in the form of either hexahydrite or epsomite, depending on the climate conditions, together with minor amounts of gypsum, nitrates and chlorides. Comparison of empirical observations with thermodynamic simulations of the salt mixture behaviour clearly showed that salt-induced damage events take place during the seasonal changes from spring to summer and winter to spring. An aqueous solution of an organic phosphonate, which in laboratory experiments was found to be an effective inhibitor of magnesium sulphate crystallization, was sprayed over a selected test area of unpainted stonework at the site. Preliminary results seem to indicate that after the application of the treatment both the amount of efflorescence and ongoing damage to the stone support is reduced. However, long-term monitoring of the future condition of the test area is needed to confirm whether indeed this treatment is appropriate and effective in reducing salt damage at this case study site. The outcome of this study extends beyond the particular problems at San Jerónimo Monastery, as it demonstrates a methodological approach for the study and evaluation of salt weathering problems affecting cultural heritage.  相似文献   

85-μm fluxes from asteroids: 2 Pallas, 7 Iris, 15 Eunomia,and 45 Eugenia     

P.D. Levan  S.D. Price 《Icarus》1984,57(1):35-41

Broad-bandpass flux measurements with effective wavelengths at 20, 27 and 85 μm are presented for four asteroids—2 Pallas, 7 Iris, 15 Eunomia, and 45 Eugenia. The observations were made during the Far Infrared Sky Survey Experiment (FIRSSE) with a super-fluid helium-cooled telescope flown to exospheric altitudes aboard a sounding rocket. The 20- and 27-μm fluxes are consistent with published 10- and 20-μm photometry. However, the 85-μm fluxes are a factor of 2 to 3 lower than a Planck law extrapolation of the shorter wavelength fluxes. If the thermal radiation from asteroids at these wavelenghts is adequately described by graybody emission, as is expected on the basis of models of asteroid radiation discussed in the literature, then the value of emissivity in the 85-μm bandpass is likely to be substantially lower than the 10- to 20-μm value. The decrease in emissivity between 20 and 85 μm suggested for these asteroids is in qualitative agreement with studies, both observational and theoretical, of emissivity of a lunar-type regolith. Fluxes measured at 20 and/or 27 μm are also reported for an additional 16 asteroids.  相似文献