Marine electrical resistivity imaging of submarine groundwater discharge: sensitivity analysis and application in Waquoit Bay, Massachusetts, USA   总被引：1，自引：0，他引：1  

Rory D. Henderson  Frederick D. Day-Lewis  Elena Abarca  Charles F. Harvey  Hanan N. Karam  Lanbo Liu  John W. Lane Jr. 《Hydrogeology Journal》2010,18(1):173-185

Electrical resistivity imaging has been used in coastal settings to characterize fresh submarine groundwater discharge and the position of the freshwater/salt-water interface because of the relation of bulk electrical conductivity to pore-fluid conductivity, which in turn is a function of salinity. Interpretation of tomograms for hydrologic processes is complicated by inversion artifacts, uncertainty associated with survey geometry limitations, measurement errors, and choice of regularization method. Variation of seawater over tidal cycles poses unique challenges for inversion. The capabilities and limitations of resistivity imaging are presented for characterizing the distribution of freshwater and saltwater beneath a beach. The experimental results provide new insight into fresh submarine groundwater discharge at Waquoit Bay National Estuarine Research Reserve, East Falmouth, Massachusetts (USA). Tomograms from the experimental data indicate that fresh submarine groundwater discharge may shut down at high tide, whereas temperature data indicate that the discharge continues throughout the tidal cycle. Sensitivity analysis and synthetic modeling provide insight into resolving power in the presence of a time-varying saline water layer. In general, vertical electrodes and cross-hole measurements improve the inversion results regardless of the tidal level, whereas the resolution of surface arrays is more sensitive to time-varying saline water layer.  相似文献   

Future changes in Central Europe heat waves expected to mostly follow summer mean warming     

Joan Ballester  Xavier Rodó  Filippo Giorgi 《Climate Dynamics》2010,35(7-8):1191-1205

Daily output from the PRUDENCE ensemble of regional climate simulations for the end of the twentieth and twenty-first centuries over Europe is used to show that the increasing intensity of the most damaging summer heat waves over Central Europe is mostly due to higher base summer temperatures. In this context, base temperature is defined as the mean of the seasonal cycle component for those calendar days when regional heat waves occur and is close, albeit not identical, to the mean temperature for July–August. Although 36–47% of future Central Europe July and August days at the end of the twenty-first century are projected to be extreme according to the present day climatology, specific changes in deseasonalized heat wave anomalies are projected to be relatively small. Instead, changes in summer base temperatures appear much larger, clearly identifiable and of the same order of magnitude as changes in the whole magnitude of heat waves. Our results bear important consequences for the predictability of central European heat wave intensity under global warming conditions.  相似文献   

A stable method for linearized inversion of elastic parameters     

M. Ali C. Tura  Lane R. Johnson 《Geophysical Journal International》1993,115(1):1-13

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Irrigated agriculture and place‐making in the East Kimberley     

Ruth Lane 《The Australian geographer》2004,35(1):77-94

This paper explores the way in which lived experiences of farmers in the Ord Valley have intersected with representations of the Ord Valley over time. I contrast the development of Stage 1 of the Ord River Irrigation Scheme in the 1960s with a proposal put forward in the late 1990s for greatly expanding the area of irrigated agriculture as Stage 2 of the scheme. I examine the rhetoric employed in planning documents and public media coverage of the first and proposed second stages of the Ord Irrigation Scheme and explore its connections with social identifications of farmers in the Ord Valley since the 1960s. I then argue the value of this approach for understanding the dynamic relationship between the spatial practices and social identifications of farmers and representations of place and land use in public media and planning processes.  相似文献   

Editorial: Earth Surface Exchanges (ESEX)     

Mike Kirkby  Stuart Lane 《地球表面变化过程与地形》2004,29(10):1171-1172

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Diatom-based Holocene paleoenvironmental records from continental sites on northeastern Ellesmere Island, high Arctic, Canada   总被引：2，自引：0，他引：2  

I. Rod Smith 《Journal of Paleolimnology》2002,27(1):9-28

Stratigraphic changes in diatom assemblages from four small lakes on northeastern Ellesmere Island, high Arctic, Canada, provide a proxy lake-ice cover and paleoenvironmental record. Low absolute diatom abundances and a benthic Fragilaria (sensu lata) dominated assemblage during the postglacial (< 7.6 ka B.P.) to mid-Holocene record the moderating effects of locally retreating glaciers. Around 5.5 ka B.P. diatom concentrations begin to rise, reaching their highest levels (10⁹ valves per g dry sediment) between 4.2 and 3 ka B.P., interpreted to be the warmest period in this region. Topoclimatic differences between lakes on Hazen Plateau and those lower in Lake Hazen Basin account for the initial decline in diatom abundances in the upper lakes after 3 ka B.P. This change is thought to reflect a lowering of the regional snowline, accordant with widely recognized Neoglacial advances on Ellesmere Island and Greenland. Lakes in lower Lake Hazen Basin maintained extensive summer ice free conditions until ~ 1.9 ka B.P., after which diatom abundances declined, suggesting prolonged summer lake-ice cover through the remainder of the recovered Holocene record. Differences between the records presented here and those from coastal areas of the Canadian high Arctic highlight the unique topoclimatic characteristics and continentality of the Lake Hazen region, and possible effects that local marine environments may have had on coastal records. Such differences serve to demonstrate the inherent geographic variability of paleoenvironmental records from the high Arctic.  相似文献   

A knowledge-based system framework for environmental perception in a subsea robotics context     

Russell  G. Lane  D. 《Oceanic Engineering, IEEE Journal of》1986,11(3):401-412

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An analytical treatment of resonance effects on satellite orbits     

Mark T. Lane 《Celestial Mechanics and Dynamical Astronomy》1987,42(1-4):3-38

A first order analytical approximation of the tesseral harmonic resonance perturbations of the Keplerian elements is presented, and the mean elements (the Keplerian elements with the long period portions averaged out) will also be given in closed form. Finally the results of a numerical test, which compares the analytical solution against a numerical integration of the Lagrange equations of motion, will be summarized.This work was sponsored with the support of the Department of the Air Force under contract F19628-85-C-0002.The views expressed are those of the author and do not reflect the official policy or position of the U.S. Government.  相似文献   

Short Period Spectral Discriminants for Explosions   总被引：1，自引：0，他引：1  

William H. Bakun  Lane R. Johnson 《Geophysical Journal International》1971,22(2):139-152

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The Deconvolution of Teleseismic P Waves from Explosions MILROW and CANNIKIN   总被引：1，自引：0，他引：1  

William H. Bakun  Lane R. Johnson 《Geophysical Journal International》1973,34(3):321-342

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