Introduction to deep earth electrical conductivity     

Campbell  W. H. 《Pure and Applied Geophysics》1990,134(4):509-509

Pure and Applied Geophysics -  相似文献   

The potential value of improved ocean observation systems in the Gulf of Mexico     

Mark J. Kaiser  Allan G. Pulsipher 《Marine Policy》2004,28(6):134

A number of coastal and ocean observation systems exist throughout the Gulf of Mexico (GOM), but the network of systems is not currently linked or integrated and at present not fully implemented. The network of local systems are diverse, typically involving unique mandates and several different funding sources at various levels of permanence. The purpose of this paper is to describe the ocean observation systems that currently exist in the GOM, and to identify and quantify the expected economic benefits that may result from the implementation of an integrated regional network. Improved ocean observation systems are expected to reduce the uncertainty of ocean/weather forecasting and to enhance the value of ocean/weather information throughout the Gulf region. The source of benefits and the size of activity from which improved ocean observation benefits may be derived are estimated for private sector, non-market, and public sector activities categorized according to marine transportation, commercial fishing, recreational fishing, search and rescue operations, and pollution management. The benefits of improved ocean observation systems to energy exploration, development, and production activities are estimated, and a discussion of potential benefits to lightering activities, environmental monitoring, royalty payments, and engineering design are highlighted.  相似文献   

Effect of the cyanide-producing bacterium Chromobacterium violaceum on ultraflat gold surfaces     

Lintern Fairbrother  Joseph G. Shapter  Joël Brugger  Gordon Southam  Allan Pring  Frank Reith 《Journal of Geochemical Exploration》2009

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Glaciation of a mixed-phase boundary layer cloud at a coastal arctic site as depicted in continuous lidar measurements     

James R. Campbell  Masataka Shiobara 《Polar Science》2008,2(2):121-127

The dynamic seeding and glaciation of a mixed-phase cloud by ice crystals injected from above at Ny Ålesund, Svalbard, Norway is described using continuous lidar measurements and thermodynamic data. Glaciation of this cloud was caused by ice crystal growth and sedimentation due to the preferential differences in saturation vapor pressure over ice versus liquid water and riming. The lidar data suggest that precipitation reached the ground for nearly 4 h as a result. The symbiosis between ice and liquid water hydrometeor presence in the polar troposphere is unique. Thermal perturbations and airmass fluctuations influence microphysical cloud characteristics and radiative balance, which makes the otherwise pristine region sensitive to lower-latitude anthropogenic and biogenic influences and a focal point for observing indirect effects and their influence on climate change. The development of lidar technologies capable of continuous and autonomous measurements is yielding important datasets to study unique atmospheric phenomena.  相似文献   

A new perceived reality: Thomas Harriot's Moon maps     

Allan Chapman 《Astronomy& Geophysics》2009,50(1):1.27-1.33

Allan Chapman considers the impact of the first telescopic observation of the heavens, made by the Englishman Thomas Harriot in July 1609.  相似文献   

Heterogenous telescope networks: An introduction     

T. Naylor  A. Allan  I. A. Steele 《Astronomische Nachrichten》2006,327(8):741-743

The first Heterogenous Telescopes Network (HTN) conference was held in July 2005. It aimed to bring together software developers, observatory staff and science users with the objective of defining the how and why of developing new ways of doing astronomical observing using geographically distributed and differently instrumented and operated telescopes. The papers included in this volume arise from that conference. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

苏格兰阿伯丁城市土壤的微生物特性研究   总被引：4，自引：0，他引：4  

杨元根  Paterson  E  Campbell  C 《矿物学报》2000,20(4):342-347

在重金属的胁迫下,阿伯丁城市土壤中微生物特征发生了显著的变化,与农村土相比,微生物基底呼吸作用明显增强,但微生物生物量却显著降低,微生物生理参数Ｃｍｉｎ／Ｃｏｒｇ、ｑＣＯ２值明显升高,Ｂｉｏｌｏｇ数据显示城市土壤对能源碳的消耗量和速度显著升高,而且对能源碳的利用方式发生了改变,但利用效率却明显降低,反映出微生物特性可作为城市土壤环境质量变异的有效指标。  相似文献   

Investigating Climate Change Impacts and Thresholds: An Application of the CLIMPACTS Integrated Assessment Model for New Zealand Agriculture   总被引：1，自引：0，他引：1  

G. J. Kenny  R. A. Warrick  B. D. Campbell  G. C. Sims  M. Camilleri  P. D. Jamieson  N. D. Mitchell  H. G. McPherson  M. J. Salinger 《Climatic change》2000,46(1-2):91-113

The determination of `critical thresholds'is an essential task for informed policydecisions on establishing greenhouse gas emissiontargets. This paper presents a framework fordetermining critical thresholds for New Zealandagriculture, focusing on three agriculturalcrops – kiwifruit, grain maize, andPaspalum dilatatum – as exemplars for the fruitproduction, arable cropping and dairy productionindustries in New Zealand. The approach is based onthe application of a country-scale, integratedassessment model, called CLIMPACTS. The CLIMPACTSsystem contains a climate change scenario generator,climate and land data, and sectoral impact models. Importantly, CLIMPACTS allows time-dependentassessments of climate change and its effects, whichfacilitates the identification and examination of thresholds, which largely relate to spatial changes, over time, in regions of economic importance for these crops. However, whether such thresholds are `critical' for New Zealand cannot currently be addressed by the CLIMPACTS model. The determination of `criticality' requires a fully integrated assessment in which the social, economic, and environmental costs and risks associated with these thresholds are comprehensively evaluated.  相似文献   

Intercomparison of Formaldehyde Measurements in Clean and Polluted Atmospheres   总被引：2，自引：0，他引：2  

L. M. Cárdenas  D. J. Brassington  B. J. Allan  H. Coe  B. Alicke  Ulrich Platt  K. M. Wilson  J. M. C. Plane  S. A. Penkett 《Journal of Atmospheric Chemistry》2000,37(1):53-80

Three different techniques used tomeasure atmospheric formaldehyde were compared duringa field campaign carried out at a clean maritime siteon the West coast of Ireland. Two spectroscopictechniques Differential Optical AbsorptionSpectroscopy (DOAS) and Tunable Diode Laser AbsorptionSpectroscopy (TDLAS), together with a glass coil/Hantzschreaction/fluorescence technique, wereemployed for measurements of atmospheric formaldehydeof the order of a few hundred pptv. The betteragreement was observed between the fluorescence andDOAS instruments.Two DOAS instruments were compared to the glasscoil/Hantzsch reaction/fluorescence technique at asemi-polluted site on the North Norfolk coast, U.K.,where concentrations of formaldehyde were observed atlevels up to 4 ppbv. A very good agreement wasobserved between the two instruments.The glass coil/Hantzsch reaction/fluorescence and theTDLAS instruments were also deployed simultaneously inorder to measure indoor air inside a mobile laboratorylocated at the Imperial College Silwood Park site nearAscot, U.K. The doors of the mobile laboratory wereleft open in order to obtain the backgroundformaldehyde concentrations. Closing them afterwardsallowed us to observe the increase in concentrationsas a result of indoor emissions. The agreement betweenthe two instruments was outstanding (correlationcoefficient was 99%).The results from this study showed that of the fourinstruments included in this intercomparison the glasscoil/Hantzsch reaction/fluorescence technique provedthe most suitable for continuous measurements offormaldehyde in the background atmosphere.  相似文献   

Sputtering of grains in C-type shocks     

P. W. May  G. Pineau des Forêts  D. R. Flower  D. Field  N. L. Allan  J. A. Purton 《Monthly notices of the Royal Astronomical Society》2000,318(3):809-816

Sputtering yields are reported for the release of Mg, Fe, Si and O under impact of He, C, O, Si and Fe on grain material composed of Mg- and Fe-bearing silicates. The yields were derived using the trim code, which simulates the results of the transport of ions in matter by means of classical Monte Carlo techniques. The energetics of the sputtering process are a key factor in the sputtering calculations, and so detailed determinations have been made of the energy with which atoms are bound to the lattice, using solid-state simulation programs. The probability of ejection of an atom is computed at a given energy, for a number of angles of incidence, and integrated to obtain the mean yield at that energy. These numerical results are then fitted with a simple function of energy for convenience in subsequent applications.
A grid of C-type shock models has been computed, using our new sputtering yields, for pre-shock densities in the range 10⁴ n _H n (H)+2 n (H₂)10⁶ cm⁻³ and shock speeds 20 v _s45 km s⁻¹. Sputtered fractions can be high, exceeding 50 per cent for shock speeds in excess of approximately 40 km s⁻¹. The column densities of Si and SiO were also computed, for comparison with observations.  相似文献