Book reviews     

Kerry Kelts  Patrick De Deckker  Françoise Gasse  Susan K. Short 《Journal of Paleolimnology》1992,7(2):173-178

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Book review     

W. E. Sharp  M. Dane Picard  Jean-François Gaillard 《Mathematical Geosciences》1992,24(4):437-447

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The volcano of Capelinhos (Azores), the solar activity and the earth-tide     

De Mendoça Dias  A. A. 《Bulletin of Volcanology》1962,24(1):211-221

Bulletin of Volcanology - Correlations on the eruptive behaviour of the volcano of Capelinhos (Fayal island) in 1957–58, with (a) solar activity, and (b) earth-tide amplitudes, by way of a...  相似文献   

The submarine volcano of Capelinhos and the tectonics of the Azores     

De Mendoça Dias  A. A. 《Bulletin of Volcanology》1962,24(1):223-231

Bulletin of Volcanology - In another paper of the author, a picture of the tectonics of the Azores was presented. The morphological analysis showed evidence of a folded and faulted structure and...  相似文献   

Investigation of Image Fusion Between High—Resolution Image and Multi—Spectral Image     

LlPingxiang WANGZhijun 《地球空间信息科学学报》2003,6(2):31-34

On the basis of a thorough understanding of the physical characteristics of remote sensing image,this paper employs the theories of wavelet transform and signal sampling to develop a new image fusion algorithm.The algorithm has been successfully applied to the image fusion of SPOT PAN and TM of Guangdong province, China The experimental results show that a perfect image fusion can be built up by using the image analytical solution and reconstruction in the image frequency domain based on the physical characteristics of the image formation.The method has demonstrated that the results of the image fusion do not change spectral characteristics of the original image.  相似文献   

东坪式与正长岩类有关的金矿床成矿机理的同位素地球化学制约     

包志伟  赵振华 《岩石学报》2006,22(10):2534-2542

东坪式金矿床产于华北地台北缘金矿成矿带的冀西北金矿集中区,构造上位于华北克拉通北缘深大断裂-尚义-赤城断裂的南侧。金矿床产于泥盆纪早期(386～410Ma)水泉沟正长岩杂岩体内及接触带附近,矿体分布受脆-韧性剪切断裂构造的制约。金矿成矿作用具有多期次的特点,成矿时代为燕山期(156～203Ma)。矿石类型主要为石英脉型、石英网脉 脉旁钾硅化蚀变岩型和钾硅化蚀变岩型,具有典型的碱性岩金矿的金-碲组合,(含)金矿物主要为自然金、碲金矿和碲金银矿。流体包裹体的 H、O 及 He 同位素研究表明,成矿流体为以大气降水主的混合热液流体并可能存在深源流体的参与。矿床的 S、Pb、Sr 和 Si 同位素组成表明,金矿成矿物质主要来源于正长岩杂岩体,部分源于太古宙桑干群变质岩和燕山期花岗岩。因此,东坪式金矿是由燕山期伸展构造环境下热液流体在上涌地幔及岩浆活动的热驱动下对泥盆纪早期形成的正长岩交代改造的产物。  相似文献   

The LMDZ4 general circulation model: climate performance and sensitivity to parametrized physics with emphasis on tropical convection   总被引：3，自引：11，他引：3  

Frédéric Hourdin  Ionela Musat  Sandrine Bony  Pascale Braconnot  Francis Codron  Jean-Louis Dufresne  Laurent Fairhead  Marie-Angèle Filiberti  Pierre Friedlingstein  Jean-Yves Grandpeix  Gerhard Krinner  Phu LeVan  Zhao-Xin Li  François Lott 《Climate Dynamics》2006,27(7-8):787-813

The LMDZ4 general circulation model is the atmospheric component of the IPSL–CM4 coupled model which has been used to perform climate change simulations for the 4th IPCC assessment report. The main aspects of the model climatology (forced by observed sea surface temperature) are documented here, as well as the major improvements with respect to the previous versions, which mainly come form the parametrization of tropical convection. A methodology is proposed to help analyse the sensitivity of the tropical Hadley–Walker circulation to the parametrization of cumulus convection and clouds. The tropical circulation is characterized using scalar potentials associated with the horizontal wind and horizontal transport of geopotential (the Laplacian of which is proportional to the total vertical momentum in the atmospheric column). The effect of parametrized physics is analysed in a regime sorted framework using the vertical velocity at 500 hPa as a proxy for large scale vertical motion. Compared to Tiedtke’s convection scheme, used in previous versions, the Emanuel’s scheme improves the representation of the Hadley–Walker circulation, with a relatively stronger and deeper large scale vertical ascent over tropical continents, and suppresses the marked patterns of concentrated rainfall over oceans. Thanks to the regime sorted analyses, these differences are attributed to intrinsic differences in the vertical distribution of convective heating, and to the lack of self-inhibition by precipitating downdraughts in Tiedtke’s parametrization. Both the convection and cloud schemes are shown to control the relative importance of large scale convection over land and ocean, an important point for the behaviour of the coupled model.  相似文献   

δ~(18)O record and temperature change over the past 100 years in ice cores on the Tibetan Plateau   总被引：6，自引：0，他引：6  

Lonnie Thompson 《中国科学D辑(英文版)》2006,(1)

1 IntroductionMeteorological stations on the Tibetan Plateau are few in number and uneven in distribution, with a majority concentrated in the east and south. No stations exist so far within the large expanse in the middle or west of the Plateau. Moreover…  相似文献   

Trace Metal Solid State Speciation in Aerosols of the Northern Levantine Basin,East Mediterranean   总被引：3，自引：0，他引：3  

Mustafa Koçak  Nilgun Kubilay  Barak Herut  Malcolm Nimmo 《Journal of Atmospheric Chemistry》2007,56(3):239-257

An established three stage sequential leach scheme was applied to a series of selected high volume aerosol samples (n = 35) collected from the Turkish Eastern Mediterranean coastline (Erdemli). Samples were selected according to their air mass back trajectory history to reflect the contrasting mixtures of aerosol material present in the Eastern Mediterranean marine aerosol. Two populations were adopted, those samples which were classed as “anthropogenic” and those which were “Saharan” dominated aerosol populations. Applying the three stage leach it was possible to define the proportion for each of the considered metals (Al, Fe, Cu, Pb, Cd, Zn and Mn) present in the (a) “exchangeable” (b) “carbonate / oxide” and (c) “refractory” phases, representing novel solid state aerosol speciation data for this marine system. Clear trends were established, conforming with data from previous studies with mainly crustal derived metals (Al and Fe) being present in the refractory phases (Al > 88%; Fe > 84%) and those influenced by anthropogenic sources being dominating in the exchangeable phase, although for these metals the variability was comparatively high (12–64%; 19–85%; 40–100% for Zn, Pb and Cd, respectively). For the majority, greater exchangeable fractions were present the lower the crustal source contribution to the aerosol population, whereas the “refractory” fraction exhibited contrasting behaviour. This was illustrated by the novel application of the mixing diagram, presenting each of the three speciation stages against the corresponding percent anthropogenic contribution to each collected sample. Zn, Pb and Cd all illustrated progressive decrease in the percent exchangeable with increasing crustal contribution to the aerosol population. The percent exchangeable was discussed in terms of its use to represent the upper limit of the bioavailable fraction of metal associated with the aerosol, post deposition. The mixing diagram approach enabled the prediction of the residual fractions for Cd, Pb and Zn (41 ± 4%; 62 ± 4% and 82 ± 5%, respectively,) in Saharan end-member material.  相似文献   

Decoupling of arsenic and iron release from ferrihydrite suspension under reducing conditions: a biogeochemical model     

André Burnol  Francis Garrido  Philippe Baranger  Catherine Joulian  Marie-Christine Dictor  Françoise Bodénan  Guillaume Morin  Laurent Charlet 《Geochemical transactions》2007,8(1):12

High levels of arsenic in groundwater and drinking water are a major health problem. Although the processes controlling the release of As are still not well known, the reductive dissolution of As-rich Fe oxyhydroxides has so far been a favorite hypothesis. Decoupling between arsenic and iron redox transformations has been experimentally demonstrated, but not quantitatively interpreted. Here, we report on incubation batch experiments run with As(V) sorbed on, or co-precipitated with, 2-line ferrihydrite. The biotic and abiotic processes of As release were investigated by using wet chemistry, X-ray diffraction, X-ray absorption and genomic techniques. The incubation experiments were carried out with a phosphate-rich growth medium and a community of Fe(III)-reducing bacteria under strict anoxic conditions for two months. During the first month, the release of Fe(II) in the aqueous phase amounted to only 3% to 10% of the total initial solid Fe concentration, whilst the total aqueous As remained almost constant after an initial exchange with phosphate ions. During the second month, the aqueous Fe(II) concentration remained constant, or even decreased, whereas the total quantity of As released to the solution accounted for 14% to 45% of the total initial solid As concentration. At the end of the incubation, the aqueous-phase arsenic was present predominately as As(III) whilst X-ray absorption spectroscopy indicated that more than 70% of the solid-phase arsenic was present as As(V). X-ray diffraction revealed vivianite Fe(II)₃(PO₄)₂.8H₂O in some of the experiments. A biogeochemical model was then developed to simulate these aqueous- and solid-phase results. The two main conclusions drawn from the model are that (1) As(V) is not reduced during the first incubation month with high Eh values, but rather re-adsorbed onto the ferrihydrite surface, and this state remains until arsenic reduction is energetically more favorable than iron reduction, and (2) the release of As during the second month is due to its reduction to the more weakly adsorbed As(III) which cannot compete against carbonate ions for sorption onto ferrihydrite. The model was also successfully applied to recent experimental results on the release of arsenic from Bengal delta sediments.  相似文献