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81.
Despite a significant period of strong economic and jobs growth nationally, there is well-established evidence in Australia that the proceeds of this growth have not been shared equally, either between places or between individuals. Empirically, it is well known that particular socioeconomic groups have a higher risk of unemployment and it has become equally well established that there are particular geographic patterns of labour market disadvantage that suggest that local geographic context is also important. What is not well understood are the ways in which phenomena at the geographic level are associated with individual-level characteristics and other social contexts in ways that negatively impact on a range of social outcomes, including unemployment. The present paper specifically addresses this issue by using a multi-scalar approach and using survey data from the Housing, Income and Labour Force Dynamics Australia (HILDA) survey and aggregate level census data to model unemployment risk. The paper argues that to better understand unemployment and to add to sound policy development, approaches that incorporate a variety of contexts, including the impact of local geographies, are important.  相似文献   
82.
There are many factors affecting submarine groundwater discharge (SGD). However, systematic study of the influences of these factors is still limited. In this study, numerical modeling is performed to quantitatively explore the influences of various factors on SGD in a coastal aquifer. In such locations, tidal and terrestrial hydraulic gradients are the primary forces driving fresh and salt water movement. Unlike steady-state flow, dynamic fresh and salt water mixing at the near-shore seafloor may form an intertidal mixing zone (IMZ) near the surface. By constructing a general SGD model, the effects of various model components such as boundary conditions, model geometry and hydraulic parameters are systematically studied. Several important findings are obtained from the study results: (1) Previous studies have indicated there will be a freshwater discharge tube between the classic transition zone and the IMZ. However, this phenomenon may become unclear with the increase of heterogeneity and anisotropy of the medium’s conductivity field. (2) SGD and IMZ are both more sensitive to the vertical anisotropy ratio of hydraulic conductivity (Kx/Kz) than to the horizontal ratio (Kx/Ky). (3) Heterogeneity of effective porosity significantly affects SGD and IMZ. (4) Increase of the storage coefficient decreases fresh water discharge but increases mixing salt water discharge and total SGD. The increase will also change the shape of the IMZ. (5) Variation of dispersivities does not affect SGD, but significantly changes the distributions of the IMZ and the whole mixing zone. These findings will be helpful to the sampling design of field studies of SGD and to the application of dynamic SGD models to field sites for model development and calibration.  相似文献   
83.
With growing importance of water resources in the world, remediations of anthropogenic contaminations due to reactive solute transport become even more important. A good understanding of reactive rate parameters such as kinetic parameters is the key to accurately predicting reactive solute transport processes and designing corresponding remediation schemes. For modeling reactive solute transport, it is very difficult to estimate chemical reaction rate parameters due to complex processes of chemical reactions and limited available data. To find a method to get the reactive rate parameters for the reactive urea hydrolysis transport modeling and obtain more accurate prediction for the chemical concentrations, we developed a data assimilation method based on an ensemble Kalman filter (EnKF) method to calibrate reactive rate parameters for modeling urea hydrolysis transport in a synthetic one-dimensional column at laboratory scale and to update modeling prediction. We applied a constrained EnKF method to pose constraints to the updated reactive rate parameters and the predicted solute concentrations based on their physical meanings after the data assimilation calibration. From the study results we concluded that we could efficiently improve the chemical reactive rate parameters with the data assimilation method via the EnKF, and at the same time we could improve solute concentration prediction. The more data we assimilated, the more accurate the reactive rate parameters and concentration prediction. The filter divergence problem was also solved in this study.  相似文献   
84.
Solid precipitation (SP) intensity ( $ R_{\text{s}} $ ) using four automatic gauges, Pluvio, PARSIVEL (PArticle, SIze and VELocity), FD12P and POSS, and radar reflectivity factor ( $ Z $ ) using the POSS and PARSIVEL were measured at a naturally sheltered station (VOA) located at high level (1,640 m) on the Whistler Mountain in British Colombia, Canada. The R s and other standard meteorological parameters were collected from March 2009, and from November 2009, to February 2010. The wind speed (ws) measured during this period ranged from 0 to 4.5 ms?1, with a mean value of 0.5 ms?1. The temperature varied from 4 to ?17 °C. The SP amount reported by the PARSIVEL was higher than that reported by the Pluvio by more than a factor of 2, while the FD12P and POSS measured relatively smaller amounts, but much closer to that reported by the Pluvio and manual measurements. The dependence of R s from the PARSIVEL on wind speed was examined, but no significant dependence was found. The PARSIVEL’s precipitation retrieval algorithm was modified and tested using three different snow density size relationships (ρ sD) reported in literature. It was found that after modification of the algorithm, the derived R s amounts using the raw data agreed reasonably well with the Pluvio. Statistical analysis shows that more than 95 % of $ Z_{{h_{\text{poss}} }} $ data measured by POSS appears to correlates well with the reflectivity factors determined using the three ρ sD relationships. The automated Pluvio accumulation and manually determined daily SP amount (SPm) measured during five winter months were compared. The mean ratio (MR) and the mean difference (MD), and the correlation coefficient (r) calculated using the data collected using the two methods, were found to be 0.96, 0.4 and 0.6 respectively, indicating respectable agreement between these two methods, with only the Pluvio underestimating the amount by about 4 %.  相似文献   
85.
A comprehensive study of mid-mountain clouds and their impacts on the Vancouver 2010 Winter Olympics and Paralympics is presented. Mid-mountain clouds were frequently present on the Whistler alpine venue, as identified in an extensive archive of webcam images over a 45-day period from February 5 to March 21, 2010. These clouds posed serious forecast challenges and had significant impacts on some Olympic and Paralympic alpine skiing competitions. Under fair weather conditions, a diurnal upslope (anabatic) flow can work in concert with a diurnal temperature inversion aloft to produce a localized phenomenon known as “Harvey’s Cloud” at Whistler. Two detailed case studies in this paper suggest that mid-mountain clouds can also develop in the area as a result of a moist valley flow interacting with a downslope flow descending from the mountaintop. A southerly inflow through the Sea-to-Sky corridor can be channeled by the local topography into a westerly upslope flow toward Whistler Mountain, resulting in orographic clouds on the alpine venue. Under favorable circumstances, these clouds are trapped to the mid-mountain zone by the leeward subsidence of an elevated southerly flow. The presence of the downslope subsidence was manifested by a distinguished dry layer observed on the top of the mid-mountain clouds in both cases. It is the subsidence-induced adiabatic warming that imposes a strong buoyant suppression to trap the mid-mountain cloud. On the other hand, the subsidence-induced dry layer has the potential to trigger evaporative instability to periodically breakup the mid-mountain cloud.  相似文献   
86.
Based on this preliminary study, existing sand and gravel mining regulations (in Maine, USA) can be inferred to provide some protection to water resources. Sand and gravel deposits are important natural resources that have dual uses: mining for construction material and pumping for drinking water. How the mining of sand and gravel affects aquifers and change aquifer vulnerability to contamination is not well documented. Mining regulations vary greatly by state and local jurisdiction. This study test metrics to measure the effectiveness of mining regulations. The sand and gravel aquifer system studied is covered with former and active gravel pits to nearly 25% of its areal extent. Data from homeowner interviews and field measurements found scant evidence of changes in water quantity. Water quality analyses collected from springs, streams, ponds and wells indicate that the aquifer was vulnerable to contamination by chloride and nitrate. However, water quality changes can not be related directly to mining activities.  相似文献   
87.
Voluminous mid-Miocene rhyolitic ash-flow tuffs and lava flows are exposed along the northern and southern margins of the central and western Snake River Plain. These rhyolites are essentially anhydrous with the general mineral assemblage of plagioclase ±sanidine ± quartz + augite + pigeonite ± hypersthene ± fayalitic olivine + Fe-Ti oxides + apatite + zircon which provides an opportunity to compare feldspar, pyroxene, and Fe-Ti oxide equilibration temperatures for the same rocks. Estimated pyroxene equilibration temperatures (based on the geothermometers of Lindsley and coworkers) range from 850 to 1000°C, and these are well correlated with whole-rock compositions. With the exception of one sample, agreement between the two-pyroxene thermometers tested is well within 50°C. Fe-Ti oxide geothermometers applied to fresh magnetite and ilmenite generally yield temperatures about 50 to 100°C lower than the pyroxene temperatures, and erratic results are obtained if these minerals exhibit effects of subsolidus oxidation and exsolution. Results of feldspar thermometry are more complicated, and reflect uncertainties in the thermometer calibrations as well as in the degree of attainment of equilibrium between plagioclase and sanidine. In general, temperatures obtained using the Ghiorso (1984) and Green and Usdansky (1986) feldspar thermometers agree with the pyroxene temperatures within the respective uncertainties. However, uncertainties in the feldspar temperatures are the larger of the two (and exceed ±60°C for many samples). The feldspar thermometer of Fuhrman and Lindsley (1988) produces systematically lower temperatures for many of the samples studied. The estimated pyroxene temperatures are considered most representative of actual magmatic temperatures for these rhyolites. This range of temperatures is significantly higher than those for rhyolites from many other suites, and is consistent with the hypothesis that the Snake River Plain rhyolitic magmas formed by partial fusion of relatively dry (e.g. granulitic) crustal lithologies.  相似文献   
88.
Hot-wire anemometers were used to measure air temperature and the three velocity components of the wind within and above a maize canopy. From digitized anemometer outputs, correlation coefficients for vertical heat flux and turbulent momentum transfer were calculated. A comparison of these coefficients with profiles of mean wind speed and mean temperature indicates that the main features of the turbulence may be explained in terms of the usual mixing-length theory. Instantaneous records of heat and momentum flux, however, indicate the existence of other competing turbulent mechanisms due to the unsteady, non-equilibrium nature of the turbulent flow. Regimes of flow dominated by mechanical and/or thermal mixing are indicated. Spectral results show that high shear and turbulent intensity levels as well as the presence of the maize leaves and stalks as vortex-shedding surfaces complicate the energy transfer mechanism. An energy balance between radiation and convection reveals that the energy budget is primarily a balance between solar radiation and the flux of latent heat.Contribution of the Sibley School of Mechanical and Aerospace Engineering, Cornell University, in cooperation with the Agricultural Research Service, U.S. Department of Agriculture, Ithaca, N.Y., U.S.A. and the Cornell University Agricultural Experiment Station. Department of Agronomy Series No. 1116.Sibley School of Mechanical and Aerospace Engineering, Cornell University; U.S. Department of Agriculture, Gainesville, Florida Section for Estuary and Fjord Studies, River and Harbour Laboratory, Technical University of Norway, Trondheim, Norway; State Univ. of New York at Buffalo; and U.S. Department of Agriculture and Cornell University; respectively.  相似文献   
89.
In 1993, during the removal of a diesel and a gasoline underground storage tank at the municipal garage of the Village of Kohler, Sheboygan County, Wisconsin, soil testing revealed environmental contamination at the site. A site investigation revealed the possibility of a second on-site source of petroleum contamination. Limited historical data and the present usage of structures within the suspected source area precluded the use of most invasive sampling methods and most geophysical techniques. A fluxgate magnetometer survey, followed by confirmatory excavation, was conducted at the site. The fluxgate magnetometer survey identified nine possible magnetic anomalies within the 18 × 25 m area. The subsequent excavation near the anomalies revealed the presence of five paired and two individual 2000 L underground storage tanks. The fluxgate magnetometer survey, although affected by the proximity of buildings, was able to detect the buried tanks within 3 m of the brick structures, using a 1.5 × 1.5 m sampling array.  相似文献   
90.
A Lagrangian perturbation method is applied to develop a method of moments for reactive solute flux through a three-dimensional, nonstationary flow field. The flow nonstationarity may stem from medium nonstationarity, finite domain boundaries, and/or fluid pumping and injecting. The reactive solute flux is described as a space–time process where time refers to the solute flux breakthrough in a control plane at some distance downstream of the solute source and space refers to the transverse displacement distribution at the control plane. The analytically derived moments equations for solute transport in a nonstationary flow field are too complicated to solve analytically; therefore, a numerical finite difference method is implemented to obtain the solutions. This approach combines the stochastic model with the flexibility of the numerical method to boundary and initial conditions. The approach provides a tool to apply stochastic theory to reactive solute transport in complex subsurface environments. Several case studies have been conducted to investigate the influence of the physical and chemical heterogeneity of a medium on the reactive solute flux prediction in nonstationary flow field. It is found that both physical and chemical heterogeneity significantly affect solute transport behavior in a nonstationary flow field. The developed method is also applied to an environmental project for predicting solute flux in the saturated zone below the Yucca Mountain Project area, demonstrating the applicability of the method in practical environmental projects.  相似文献   
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