Monitoring well placement using conditional simulation of hydraulic head   总被引：1，自引：0，他引：1  

Dale H. Easley  Leon E. Borgman  Dennis Weber 《Mathematical Geology》1991,23(8):1059-1080

A theoretical technique for conditioning simulations in frequency domain is developed and then applied to a hydraulic-head data set from Pittman, Nevada. Frequency-domain simulation rapidly generates simulations while requiring minimal computer memory. This makes it possible by using a personal computer to create large numbers of simulations of a physical parameter field for use in studying stochastic processes. In our application, groundwater flowlines are constructed from the simulations of the hydraulic head field. Then, the crossings of the flowlines at a transect down-stream from a contaminant point source generate histograms for predicting the probability of plume interception by groundwater monitoring wells. The simulation process is discussed in detail for the Pittman study site.  相似文献   

On the surface temperature of Greek waters     

Prof. Dr. Leon N. Carapiperis 《Pure and Applied Geophysics》1952,23(1):153-161

Summary This study deals with the surface temperature of Greek seas. The general distribution of this element for the months February, May, August and November is given and the factors controlling the sea-surface temperature are examined. In addition the annual variation and the monthly variability of the sea surface temperature are studied, as well as the difference between the sea-surface and air temperature in three different regions of Greek waters.

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Résumé Cette étude concerne la température de la surface des mers de la Grèce. La distribution générale de cet élément pour les mois de Février, Mai, Août et November est donnée et les facteurs qui contrôlent la température de la mer sont examinés. De plus la variabilité mensuelle de la température de la surface de la mer ainsi que la différence qui existe entre la température de la surface de la mer et la température de l'air dans trois différentes régions des mers Grecques.

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Optimal Technology R&D in the Face of Climate Uncertainty     

Erin Baker  Leon Clarke  John Weyant 《Climatic change》2006,78(1):157-179

This paper explores optimal near-term technology R&D in the face of uncertain damages caused by the buildup of greenhouse gases. The paper puts particular emphasis on understanding how optimal near-term R&D expenditures might vary based on the technologies pursued in the R&D program. The exploration is conducted in the context of varying impacts from R&D on the global abatement cost function. The R&D planning problem is considered first within a theoretical framework and is then pursued in a stylized application using the DICE model. The paper provides intuition into the circumstances under which near-term technology R&D might increase or decrease under uncertainty, thereby serving as a hedge against climate uncertainty.  相似文献   

GeoPyTool:A cross-platform software solution for common geological calculations and plots   总被引：1，自引：0，他引：1  

Qiu-Ye Yu  Leon Bagas b  Ping-Hua Yang  Da Zhang 《地学前缘(英文版)》2019,10(4):1437-1447

GeoPyTool is an open source application developed for geological calculations and plots,such as geochemical classification,parameter calculation,basic statistical analysis and diagrams for structural geology.More than acting as a link from raw data stored in Microsoft Excel~(?)(MS Excel)files to vector graphic files,GeoPyTool includes recently developed routines that have not been included in previous software,such as the calculation of the Ce~((Ⅳ))/Ce~((Ⅲ))ratio for zircons as a method to examine the temporal evolution of oxygen fugacity in the magmatic source for igneous rocks,and the temperature calculator with titanium in zircon and zirconium in rutile.Besides these routines,GeoPyTool also allows users to load any figure from articles or books as a base map.As a Python-based crossplatform program,GeoPyTool works on Windows~(?),MacOS X~(?)and GNU/Linux.GeoPyTool can do the whole process from data to results without the dependence of Microsoft Excel~(?),CorelDraw~(?) and other similar software.It takes Excel~(?)XLSX and CSV(Comma Separated Value)as the formats of both the input data source files and the output calculation results files.The figures generated by GeoPyTool can be saved as portable network graphics(PNG),scalable vector graphics(SVG)or portable document format(PDF).Another highlight of GeoPyTool is the multilingual support,the official versio n of GeoPyTool supports both Chinese and English,and additional languages can be loaded through interface files.GeoPyTool is still in the development stage and will be expanded with further geochemical and structural geology routines.As an open source project,all source code of GeoPyTool are accessible on Github(https://github.com/GeoPyTool/GeoPyTool).Users with Python experience can join in the development team and build more complex functions expanding the capabilities of GeoPyTool.  相似文献   

3D modelling of dreissenid mussel impacts on phytoplankton in a large lake supports the nearshore shunt hypothesis and the importance of wind-driven hydrodynamics     

Astrid N. Schwalb  Damien Bouffard  Leon Boegman  Luis Leon  Jennifer G. Winter  Lewis A. Molot  Ralph E. H. Smith 《Aquatic Sciences - Research Across Boundaries》2015,77(1):95-114

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Post-Impulsive-Phase Acceleration in a Wide Range of Solar Longitudes     

Kocharov  Leon  Torsti  Jarmo  Laitinen  Timo  Teittinen  Matti 《Solar physics》1999,190(1-2):295-307

We have analyzed five solar energetic particle (SEP) events observed aboard the SOHO spacecraft during 1996–1997. All events were associated with impulsive soft X-ray flares, Type II radio bursts and coronal mass ejections (CMEs). Most attention is concentrated on the SEP acceleration during the first 100 minutes after the flare impulsive phase, post-impulsive-phase acceleration, being observed in eruptions centered at different solar longitudes. As a representative pattern of a (nearly) well-connected event, we consider the west flare and CME of 9 July 1996 (S10 W30). Similarities and dissimilarities of the post-impulsive-phase acceleration at large heliocentric-angle distance from the eruption center are illustrated with the 24 September 1997 event (S31 E19). We conclude that the proton acceleration at intermediate scales, between flare acceleration and interplanetary CME-driven shock acceleration, significantly contributes to the production of ≳10 MeV protons. This post-impulsive-phase acceleration seems to be caused by the CME lift-off.  相似文献   

Evaluation and comparison of interpolated gauge rainfall data and gridded rainfall data in Florida,USA     

Meijing Zhang  Conrado de Leon 《水文科学杂志》2018,63(4):561-582

A variety of spatially continuous rainfall products are available but little evaluation of their accuracy has been published for areas with high spatial variability in rainfall. Five gridded rainfall products (PRISM, RTMA, and the interpolated Florida Automated Weather Network, FAWN, rainfall layers based on three interpolated methods) were assessed for Florida State. Point-to-pixel and pixel-to-pixel comparisons were performed to compare the five products. On average, the PRISM and RTMA products resulted in a better fit with the daily FAWN rainfall datasets, while FAWN-based interpolated products resulted in a better fit with the monthly FAWN rainfall datasets based on point-to-pixel analysis. Inverse distance weighting and ordinary kriging methods performed slightly better than the thin plate spline method in predicting daily rainfall. In general, monthly and seasonal rainfall amounts from PRISM and RTMA products were higher and lower, respectively, than reference rainfall amounts from FAWN gauge stations and FAWN-based interpolated products.  相似文献   

Testing the utility of structure‐from‐motion photogrammetry reconstructions using small unmanned aerial vehicles and ground photography to estimate the extent of upland soil erosion   总被引：1，自引：0，他引：1       下载免费PDF全文

Miriam Glendell  Gareth McShane  Luke Farrow  Mike R. James  John Quinton  Karen Anderson  Martin Evans  Pia Benaud  Barry Rawlins  David Morgan  Lee Jones  Matthew Kirkham  Leon DeBell  Timothy A. Quine  Murray Lark  Jane Rickson  Richard E. Brazier 《地球表面变化过程与地形》2017,42(12):1860-1871

Quantifying the extent of soil erosion at a fine spatial resolution can be time consuming and costly; however, proximal remote sensing approaches to collect topographic data present an emerging alternative for quantifying soil volumes lost via erosion. Herein we compare terrestrial laser scanning (TLS), and both unmanned aerial vehicle (UAV) and ground photography (GP) structure‐from‐motion (SfM) derived topography. We compare the cost‐effectiveness and accuracy of both SfM techniques to TLS for erosion gully surveying in upland landscapes, treating TLS as a benchmark. Further, we quantify volumetric soil loss estimates from upland gullies using digital surface models derived by each technique and subtracted from an interpolated pre‐erosion surface. Soil loss estimates from UAV and GP SfM reconstructions were comparable to those from TLS, whereby the slopes of the relationship between all three techniques were not significantly different from 1:1 line. Only for the TLS to GP comparison was the intercept significantly different from zero, showing that GP is more capable of measuring the volumes of very small erosion features. In terms of cost‐effectiveness in data collection and processing time, both UAV and GP were comparable with the TLS on a per‐site basis (13.4 and 8.2 person‐hours versus 13.4 for TLS); however, GP was less suitable for surveying larger areas (127 person‐hours per ha^?1 versus 4.5 for UAV and 3.9 for TLS). Annual repeat surveys using GP were capable of detecting mean vertical erosion change on peaty soils. These first published estimates of whole gully erosion rates (0.077 m a^?1) suggest that combined erosion rates on gully floors and walls are around three times the value of previous estimates, which largely characterize wind and rainsplash erosion of gully walls. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Book Review of Dynamic Sun Edited by Bhola Dwivedi,Foreward by Eugene N. Parker,Cambridge University Press,Cambridge, New York, 2003, 462 pp., £65.00, $90.00, hardback (ISBN 05-2181057-4)     

Leon Mestel 《地球物理与天体物理流体动力学》2013,107(5):424-427

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RCP4.5: a pathway for stabilization of radiative forcing by 2100   总被引：3，自引：2，他引：1  

Allison M. Thomson  Katherine V. Calvin  Steven J. Smith  G. Page Kyle  April Volke  Pralit Patel  Sabrina Delgado-Arias  Ben Bond-Lamberty  Marshall A. Wise  Leon E. Clarke  James A. Edmonds 《Climatic change》2011,109(1-2):77-94

Representative Concentration Pathway (RCP) 4.5 is a scenario that stabilizes radiative forcing at 4.5?W?m^?2 in the year 2100 without ever exceeding that value. Simulated with the Global Change Assessment Model (GCAM), RCP4.5 includes long-term, global emissions of greenhouse gases, short-lived species, and land-use-land-cover in a global economic framework. RCP4.5 was updated from earlier GCAM scenarios to incorporate historical emissions and land cover information common to the RCP process and follows a cost-minimizing pathway to reach the target radiative forcing. The imperative to limit emissions in order to reach this target drives changes in the energy system, including shifts to electricity, to lower emissions energy technologies and to the deployment of carbon capture and geologic storage technology. In addition, the RCP4.5 emissions price also applies to land use emissions; as a result, forest lands expand from their present day extent. The simulated future emissions and land use were downscaled from the regional simulation to a grid to facilitate transfer to climate models. While there are many alternative pathways to achieve a radiative forcing level of 4.5?W?m^?2, the application of the RCP4.5 provides a common platform for climate models to explore the climate system response to stabilizing the anthropogenic components of radiative forcing.  相似文献