نتایج جستجو برای: groundwater variations

تعداد نتایج: 214290  

2005
Francisco W. Cruz Ivo Karmann Oduvaldo Viana Stephen J. Burns José A. Ferrari Mathias Vuille Alcides N. Sial Marcelo Z. Moreira

We analyze the interannual monthly variability of oxygen isotope ratios in data from IAEA stations along the Atlantic coast of South America between 238 and 348 S to evaluate the influence of parameters such as temperature, rainfall amount and moisture source contribution on meteoric water recharging two karst systems in subtropical Brazil. In addition, a 2 year monitoring program performed on ...

2008
Xing Yuan Zhenghui Xie Jing Zheng Xiangjun Tian Zongliang Yang

[1] Groundwater is an important component of the hydrologic cycle, and its anomaly will result in variations of soil moisture, water, and energy balances between the land surface and atmosphere, which ultimately influence climate. In this study, we implement a groundwater model into the regional climate model RegCM3, which is called RegCM3_GW, and investigate the effects of water table dynamics...

2002
L. Ruiz V. Beaujouan

The hydrological and biogeochemical monitoring of catchments has become a common approach for studying the effect of the evolution of agricultural practices on water resources. In numerous studies, the catchment is used as a “mega-lysimeter” to calculate annual input-output budgets. However, the literature reflects two opposite interpretations of the trends of nitrate concentration in streamwat...

2002
NATHANIEL E. OSTROM LARS O. HEDIN PHILIP ROBERTSON

The natural removal of NO3 by denitrification within riparian zones of streams and rivers is an area of considerable interest owing to its potential to minimize the impacts of excess anthropogenic loadings. In this study we utilize natural variations in stable N isotopic compositions of NO3 and NH4 within a transect of shallow wells extending 4 m inland from Smith Creek, a southwestern Michigan...

2014
Rasmus Houborg Matthew Rodell Bailing Li Rolf Reichle Benjamin Zaitchik Benjamin F. Zaitchik

Drought indicators based on model-assimilated Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage observations" (2012). NASA Publications. [1] The Gravity Recovery and Climate Experiment (GRACE) twin satellites observe time variations in Earth's gravity field which yield valuable information about changes in terrestrial water storage (TWS). GRACE is characterized by low sp...

2003
Martin O. Saar Michael Manga

Groundwater recharge at Mt. Hood, Oregon, is dominated by spring snow melt which provides a natural largeamplitude and narrow-width pore-fluid pressure signal. Time delays between this seasonal groundwater recharge and seismicity triggered by groundwater recharge can thus be used to estimate large-scale hydraulic diffusivities and the state of stress in the crust. We approximate seasonal variat...

2010
M. Musgrove

0022-1694/$ see front matter Published by Elsevier doi:10.1016/j.jhydrol.2010.04.036 * Corresponding author at: US Geological Survey, 1505 Ferguson Lane, Austin, TX 78754, United States. E-mail address: [email protected] (M. Musgrov A two and a half year study of two adjacent watersheds at the Honey Creek State Natural Area (HCSNA) in central Texas was undertaken to evaluate spatial and tempora...

Journal: :Geochemical Transactions 2008
Jerome Métral Laurent Charlet Sara Bureau Sukumar Basu Mallik Sudipta Chakraborty Kazi M Ahmed MW Rahman Zhongqi Cheng Alexander van Geen

BACKGROUND The origin of the spatial variability of dissolved As concentrations in shallow aquifers of the Bengal Basin remains poorly understood. To address this, we compare here transects of simultaneously-collected groundwater and aquifer solids perpendicular to the banks of the Hooghly River in Chakdaha, India, and the Old Brahmaputra River in Araihazar, Bangladesh. RESULTS Variations in ...

Journal: :Journal of environmental radioactivity 2008
P P Povinec H Bokuniewicz W C Burnett J Cable M Charette J-F Comanducci E A Kontar W S Moore J A Oberdorfer J de Oliveira R Peterson T Stieglitz M Taniguchi

Results of groundwater and seawater analyses for radioactive (3H, 222Rn, 223Ra, 224Ra, 226Ra, and 228Ra) and stable (D and 18O) isotopes are presented together with in situ spatial mapping and time series 222Rn measurements in seawater, direct seepage measurements using manual and automated seepage meters, pore water investigations using different tracers and piezometric techniques, and geoelec...

2009
Y. Jia H. Wang

A distributed model for simulating the land surface hydrological processes in the Heihe river basin was developed and validated on the basis of considering the physical mechanism of hydrological cycle and the artificial system of water utilization in the basin. Modeling approach of every component process was introduced from 2 aspects, i.e., water cycle and energy cycle. The hydrological proces...

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