Comparative assessment of spatiotemporal snow cover changes and hydrological behavior of the Gilgit,Astore and Hunza River basins (Hindukush–Karakoram–Himalaya region,Pakistan)     

Adnan Ahmad Tahir  Jan Franklin Adamowski  Pierre Chevallier  Ayaz Ul Haq  Silvia Terzago 《Meteorology and Atmospheric Physics》2016,128(6):793-811

  相似文献   

Rainfall–runoff model parameter estimation and uncertainty evaluation on small plots          下载免费PDF全文

Keewook Kim  Gene Whelan  S. Thomas Purucker  Thomas F. Bohrmann  Michael J. Cyterski  Marirosa Molina  Yin Gu  Yakov Pachepsky  Andrey Guber  Dorcas H. Franklin 《水文研究》2014,28(20):5220-5235

Four seasonal rainfall simulations in 2009 and 2010 were applied to a field containing 36 plots (0.75 × 2 m each), resulting in 144 runoff events. In all simulations, a constant rate of rainfall was applied then halted 60 min after initiation of runoff, with plot‐scale monitoring of runoff every 5 min during that period. Runoff was simulated with the Kinematic Runoff and Erosion/Simulator of Transport with Infiltration and Runoff (KINEROS2/STWIR) field‐scale model, whose hydrodynamics are based on the kinematic wave equation. Because of the non‐linear nature of the model and a highly parameterized model with respect to the available data, several approaches were investigated to upscale nine runoff‐related parameters from a series of small monitored plots to the field scale. Inverse modeling was performed using the model‐independent Parameter ESTimation (PEST) algorithm to individually calibrate the nine KINEROS2/STWIR parameters on 36 plots. The parameters were averaged, and bootstrapping was used to assess uncertainty of the parameters via estimation of confidence intervals (CI). A Monte Carlo simulation using the bootstrap results showed reasonable field‐scale representation of flow rates. Median values of calibrated parameters were within the 95% CI obtained with bootstrapping. The simulated results for the median values associated with the 90% CI flow rates produced similar trends as those exhibited with the observed data, suggesting that median values of the calibrated parameters from the PEST inverse modeling could be used to represent the field scale. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Tracer tests and the structure of permeability in the Corallian limestone aquifer of northern England, UK     

Aidan Foley  Gerd Cachandt  Janine Franklin  Fergus Willmore  Tim Atkinson 《Hydrogeology Journal》2012,20(3):483-498

The Corallian limestone of northern England (UK) is widely exploited for water supplies and exhibits the karstic phenomena of sinking rivers, conduit development and groundwater velocities of several kilometres per day. To test a number of model-derived source protection zones and elucidate contaminant transport mechanisms in the aquifer, three tracer tests were conducted from a set of swallow-holes draining the River Derwent toward public water supply wells in the eastern part of the aquifer. Tracers used included: Enterobacter cloacae (bacteriophage), Photine C (optical brightener), sodium fluorescein (fluorescent dye) and sulphur hexafluoride (dissolved gas), the varying properties of which make them suitable analogues for different types of potential contaminant. Observed tracer transport times and arrival patterns indicate that tracer transport occurs through karstic channels embedded in a network of primary fissures which exert control over tracer concentrations once initial tracer plumes have passed. A dipole flow system is observed between the swallow-holes and the closest abstraction well, whilst previously modelled source protection zones do not accurately reflect either groundwater velocity or those areas of the aquifer supplying the wells. These findings imply that managing such aquifers for potential contamination should rely upon empirical tracer evidence for source-protection zone modelling.  相似文献   

Crystal Structure and Chemical Composition of Ludwigite from Vranovac Ore Deposit (Boranja Mountain,Serbia)     

Pavle TAN?I?  Radovan DIMITRIJEVI?  Maja POZNANOVI?  Aleksandar PA?EVSKI  Slobodanka SUDAR 《《地质学报》英文版》2012,86(6):1524-1538

The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) ?; b=12.3109(2) ?; c=3.03712(7) ?; and V=345.91(1) ?3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.  相似文献   

Lessons from a legend--Patrick Domenico     

Schwartz FW  Fang YC 《Ground water》2007,45(1):110-113

  相似文献   

Spaces of colonialism: Delhi's urban governmentalities - by Stephen Legg     

Franklin Ginn 《Area》2009,41(1):109-110

  相似文献   

Hydrogeophysical Methods for Analyzing Aquifer Storage and Recovery Systems     

Burke J. Minsley  Jonathan Ajo‐Franklin  Amitabha Mukhopadhyay  Frank Dale Morgan 《Ground water》2011,49(2):250-269

Hydrogeophysical methods are presented that support the siting and monitoring of aquifer storage and recovery (ASR) systems. These methods are presented as numerical simulations in the context of a proposed ASR experiment in Kuwait, although the techniques are applicable to numerous ASR projects. Bulk geophysical properties are calculated directly from ASR flow and solute transport simulations using standard petrophysical relationships and are used to simulate the dynamic geophysical response to ASR. This strategy provides a quantitative framework for determining site‐specific geophysical methods and data acquisition geometries that can provide the most useful information about the ASR implementation. An axisymmetric, coupled fluid flow and solute transport model simulates injection, storage, and withdrawal of fresh water (salinity ～500 ppm) into the Dammam aquifer, a tertiary carbonate formation with native salinity approximately 6000 ppm. Sensitivity of the flow simulations to the correlation length of aquifer heterogeneity, aquifer dispersivity, and hydraulic permeability of the confining layer are investigated. The geophysical response using electrical resistivity, time‐domain electromagnetic (TEM), and seismic methods is computed at regular intervals during the ASR simulation to investigate the sensitivity of these different techniques to changes in subsurface properties. For the electrical and electromagnetic methods, fluid electric conductivity is derived from the modeled salinity and is combined with an assumed porosity model to compute a bulk electrical resistivity structure. The seismic response is computed from the porosity model and changes in effective stress due to fluid pressure variations during injection/recovery, while changes in fluid properties are introduced through Gassmann fluid substitution.  相似文献   

Design and evaluation of a geovisual analytics system for uncovering patterns in spatio-temporal event data     

Anthony C. Robinson  Donna J. Peuquet  Scott Pezanowski  Franklin A. Hardisty  Brian Swedberg 《制图学和地理信息科学》2013,40(3):216-228

ABSTRACT

It remains difficult to develop a clear understanding of geo-located events and their relationships to one another, particularly when it comes to identifying patterns of events in less-structured textual sources, such as news feeds and social media streams. Here we present a geovisualization tool that can leverage computational methods, such as T-pattern analysis, for extracting patterns of interest from event data streams. Our system, STempo, includes coordinated-view geovisualization components designed to support visual exploration and analysis of event data, and patterns extracted from those data, in terms of time, geography, and content. Through a user evaluation, we explore the usability and utility of STempo for understanding patterns of recent political, social, economic, and military events in Syria.  相似文献   

Investigating snowpack across scale in the northern Great Lakes–St. Lawrence forest region of Central Ontario,Canada     

Andy D. Beaton  Robert A. Metcalfe  James M. Buttle  Steven E. Franklin 《水文研究》2019,33(26):3310-3329

This study investigates scaling issues by evaluating snow processes and quantifying bias in snowpack properties across scale in a northern Great Lakes–St. Lawrence forest. Snow depth and density were measured along transects stratified by land cover over the 2015/2016 and 2016/2017 winters. Daily snow depth was measured using a time‐lapse (TL) camera at each transect. Semivariogram analysis of the transect data was conducted, and no autocorrelation was found, indicating little spatial structure along the transects. Pairwise differences in snow depth and snow water equivalent (SWE) between land covers were calculated and compared across scales. Differences in snowpack between forested sites at the TL points corresponded to differences in canopy cover, but this relationship was not evident at the transect scale, indicating a difference in observed process across scale. TL and transect estimates had substantial bias, but consistency in error was observed, which indicates that scaling coefficients may be derived to improve point scale estimates. TL and transect measurements were upscaled to estimate grid scale means. Upscaled estimates were compared and found to be consistent, indicating that appropriately stratified point scale measurements can be used to approximate a grid scale mean when transect data are not available. These findings are important in remote regions such as the study area, where frequent transect data may be difficult to obtain. TL, transect, and upscaled means were compared with modelled depth and SWE. Model comparisons with TL and transect data indicated that bias was dependent on land cover, measurement scale, and seasonality. Modelled means compared well with upscaled estimates, but model SWE was underestimated during spring melt. These findings highlight the importance of understanding the spatial representativeness of in situ measurements and the processes those measurements represent when validating gridded snow products or assimilating data into models.  相似文献   

For Whom Do We Write? Suggestions for Getting Read in the 21st Century     

Randall J. Hunt  Franklin W. Schwartz 《Ground water》2014,52(2):163-164

  相似文献