Possibilities of soil spectroscopy for the classification of contaminated areas in river floodplains     

Lammert Kooistra  Ron Wehrens  Lutgarde MC Buydens  Rob S. E. W. Leuven  Piet H Nienhuis 《International Journal of Applied Earth Observation and Geoinformation》2001,3(4):337

During the past decades, large amounts of diffuse contaminated soil material have been deposited in the floodplains of the river Rhine in the Netherlands. The dynamic character of this river causes a large spatial variability in the contamination level of its floodplain soils. Characterisation of the spatial variability exclusively based on soil sampling and analysis is often insufficient and expensive. Hyperspectral images can provide additional spatial information for a proper characterisation of the contamination situation of river floodplains. This paper describes the possible application of soil spectroscopy to estimate metal concentration levels in river floodplains. Soil reflectance spectra in the visible-near infrared region (VNIR) were measured in the laboratory for soil samples taken from two river floodplains along the river Waal, the main tributary of the river Rhine in the Netherlands. A multivariate calibration procedure using partial least squares (PLS) regression was applied to establish a relationship between reflectance spectra in the visible-near infrared (VNIR) region and spectrally active soil characteristics (organic matter and clay content) that are intercorrelated with concentration levels of Cd and Zn. Results of the analysis of two river floodplains are summarised and the influence of scale-level and sub soil material on the prediction capability is discussed.  相似文献   

A technique for the calculation of time dependent wind driven currents     

D.G. Mountain  K.A. Mooney 《Ocean Engineering》1979,6(5):541-547

A technique has been presented that allows for the estimation of the wind driven current or transport due to an arbitrary, time dependent wind through simple calculations. The limitations involved are primarily those inherent in an Ekman force balance. The technique is useful where an immediatem, operational requirement exists to estimate the local wind driven current.  相似文献   

A New Octahedrite from South Africa     

MATTHIAS F. COMERFORD  ROBERT H. MC CORKELL  SAMUEL W. TISHLER 《Meteoritics & planetary science》1968,4(1):7-21

Abstract Examination of an iron meteorite found in South Africa discloses it to be a coarse octahedrite containing 6.90 weight-percent nickel. The meteorite body contains several inclusions of troilite, or troilite plus graphite, and at least one of pure graphite veined with kamacite. Kamacite, cohenite, and phosphides are the other major constituents of the structure.  相似文献   

基于数字滑坡技术的暴雨滑坡、泥石流预警、监测模型研究   总被引：3，自引：1，他引：2       下载免费PDF全文

王治华  郭兆成  杜明亮  程尊兰 《地学前缘》2011,18(5):303-309

中国学者在暴雨滑坡、泥石流预测预报研究领域取得的成果为采用数字滑坡技术进行暴雨滑坡、泥石流预警、监测模型研究提供了宝贵的基础,应用数字滑坡技术建立暴雨滑坡、泥石流预测模型的原则是：（1）必须在滑坡、泥石流形成条件理论指导下;（2）应了解研究区地质环境及滑坡、泥石流特征;（3）就基于数字滑坡技术而言,只能选取遥感方法可能...  相似文献   

The effect of f(T) gravity on an interplanetary clock and its time transfer link   总被引：1，自引：0，他引：1  

Xue-Mei Deng  Yi Xie 《天文和天体物理学研究(英文版)》2013,(10):1225-1230

As an extension of the"teleparallel"equivalent of general relativity,f(T)gravity is proposed to explain some puzzling cosmological behaviors,such as accelerating expansion of the Universe.Given the fact that modified gravity also has impacts on the Solar System,we might test it during future interplanetary missions with ultrastable clocks.In this work,we investigate the effects of f(T)gravity on the dynamics of the clock and its time transfer link.Under these influences,theΛ-term and theα-term of f(T)gravity play important roles.Here,Λis the cosmological constant andαrepresents a model parameter in f(T)gravity that determines the divergence from teleparallel gravity at the first order approximation.We find that the signal of f(T)gravity in the time transfer is much more difficult to detect with the current state of development for clocks than those effects on dynamics of an interplanetary spacecraft with a bounded orbit with parameters 0.5 au≤a≤5.5 au and 0≤e≤0.1.  相似文献   

Hack's law of debris-flow basins     

LEE C. F  BEIGHLEY R. E 《国际泥沙研究》2009,24(1)

Hack's law was originally derived from basin statistics for varied spatial scales and regions.The exponent value of the law has been shown to vary between 0.47 and 0.70,causing uncertainty in its application.This paper focuses on the emergence of Hack's law from debris-flow basins in China.Over 5,000 debris-flow basins in different regions of China with drainage areas less than 100km2 are included in this study.Basins in the different regions are found to present similar distributions.Hack's law is derived fi'om maximum probability and conditional distributions,suggesting that the law should describe some critical state of basin evolution.Results suggest the exponent value is approximately 0.5.Further analysis indicates that Hack's law is related to other scaling laws underlying the evolution of a basin and that the exponent is not dependent on basin shape but rather on the evolutionary stage.A case study of a well known debris-flow basin further confirms Hack's law and its implications in basin evolution.  相似文献   

SIMS Pb/Pb dating of Zr-rich minerals in lunar meteorites Miller Range 05035 and LaPaz Icefield 02224:Implications for the petrogenesis of mare basalt   总被引：1，自引：0，他引：1  

HSU WeiBiao 《中国科学:地球科学(英文版)》2010,(3)

Miller Range (MIL) 05035 and LaPaz Icefield (LAP) 02224 are unbrecciated lunar basalt meteorites. In this report, we studied their petrography and mineralogy and made in situ uranogenic Pb/Pb dating of Zr-rich minerals. Petrography and mineralogy of these two lunar meteorites are consistent with previous investigations. The zirconolite Pb/Pb age of MIL 05035 is 3851±8 Ma (2σ), in excellent agreement with previous reports. This age suggests that MIL 05035 could be paired with Asuka 881757, a low-Ti mare basalt meteorite. The magmatic event related to MIL 05035 was probably due to the late heavy impact bom- bardment on the moon around 3.9 Ga. One baddeleyite grain in LAP 02224 shows a large variation of Pb/Pb age, from 3109±29 to 3547±21 Ma (2σ), much older than the whole-rock age of the same meteorite (~3.02±0.03 Ga). The other baddeleyite grain in LAP 02224 has an age of 3005±17 Ma (2σ). The result indicates that the minimum crystallization age of LAP 02224 is ~3.55 Ga and the younger ages could reflect late thermal disturbance on U-Pb system.  相似文献   

Large-Area Back-Illuminated CCD Imager Development     

B. E. Burke  J. A. Gregory  R.W. Mountain  B. B. Kosicki  E. D. Savoye  P. J. Daniels  V. S. Dolat  T. L. Lind  A. H. Loomis  D. J. Young  G. A. Luppino  J. L. Tonry 《Experimental Astronomy》1998,8(1):31-40

We describe recent work in the area of large, back-illuminated CCD imagers at M.I.T. Lincoln Laboratory as well as new technology applicable to astronomy. We completed in 1995 the development of a 2560 x 1960-pixel frame-transfer imager that filled a 100-mm wafer and several back-illuminated versions of this device were completed. More recently we have begun the development, in collaboration with the U. of Hawaii, of a three-side abuttable 2k x 4k CCD for a multi-chip focal plane. In the unused chord area of the wafer layout, we added test imagers as development vehicles for blooming control and for the demonstration of a CCD that is capable of charge transfer in all four directions. We expect the latter to find application as an electronic means of performing tip-tilt correction to compensate for atmospheric turbulence.  相似文献   

Balancing end-to-end budgets of the Georges Bank ecosystem     

J.H. Steele  J.S. Collie  D.J. Gifford  J.S. Link  M.E. Sieracki  D.G. Mountain  D. Palka 《Progress in Oceanography》2007,74(4):423-448

Oceanographic regimes on the continental shelf display a great range in the time scales of physical exchange, biochemical processes and trophic transfers. The close surface-to-seabed physical coupling at intermediate scales of weeks to months means that the open ocean simplification to a purely pelagic food web is inadequate. Top-down trophic depictions, starting from the fish populations, are insufficient to constrain a system involving extensive nutrient recycling at lower trophic levels and subject to physical forcing as well as fishing. These pelagic-benthic interactions are found on all continental shelves but are particularly important on the relatively shallow Georges Bank in the northwest Atlantic. We have generated budgets for the lower food web for three physical regimes (Well-mixed, Transitional and Stratified) and for three seasons (Spring, Summer and Fall/Winter). The calculations show that vertical mixing and lateral exchange between the three regimes are important for zooplankton production as well as for nutrient input. Benthic suspension feeders are an additional critical pathway for transfers to higher trophic levels. Estimates of production by mesozooplankton, benthic suspension feeders and deposit feeders, derived primarily from data collected during the GLOBEC years of 1995-1999, provide input to an upper food web. Diets of commercial fish populations are used to calculate food requirements in three fish categories, planktivores, benthivores and piscivores, for four decades, 1963-2002, between which there were major changes in the fish communities. Comparisons of inputs from the lower web with fish energetic requirements for plankton and benthos indicate that we obtained reasonable agreement for the last three decades, 1973-2002. However, for the first decade, the fish food requirements were significantly less than the inputs. This decade, 1963-1972, corresponds to a period characterized by a strong Labrador Current and lower nitrate levels at the shelf-edge, demonstrating how strong bottom-up physical forcing may determine overall fish yields.  相似文献   

Infrared instruments for the Gemini 8-M telescopes     

Matt Mountain  David Robertson 《Experimental Astronomy》1994,3(1-4):305-308

The Gemini Telescopes are being built to exploit the splendid infrared sites of Mauna Kea in Hawaii and Cerro Pachon in Chile. Both telescopes are being designed to deliver 0.1 arcsecond images at 2.2 m to the focal plane. This image size includes all tracking and enclosure effects. To exploit the superb infrared characteristics of the sites and telescopes we will require a new generation of IR instruments which will challenge both instrument designers and infrared array technologies.  相似文献