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ABRUPT WARMING OF GLOBAL CLIMATE IN THE 1980S

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Chinese Science Bulletin 1992年第20期37卷 1713-1716页

作者：衣育红王绍武 department of geophysics Peking University Beijing 100871 PRC

Ⅰ. INTRODUCTION Warming of global climate in the last one hundred years is one of the hot topics in the studies of the climatic change. It is generally acknowledged that the increasing of greenhouse gases, such as CO2, which enhances the greenhouse effect, is responsible for the warming of global climate in the 20th century, especially in the 1980s.

关键词： global warming abrupt change climatic change greenhouse effect

Receiver function imaging in strongly laterally heterogeneous crust:Synthetic modeling of BOLIVAR data

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Earthquake Science 2011年第1期24卷 45-54页

作者： A.Levander department of Earth Science Center for Computational GeophysicsRice University

We resolve a large （-20 km） discrepancy in Moho depth determined from PdS receiver functions （RFs） and from active source seismic profiling in the complex Caribbean-South American plate boundary zone in eastern Venezuela. As part of the BOLIVAR experiment 20 broadband stations were deployed along an active source profile to record teleseisms. Using the extremely heterogeneous crustal model obtained from active source data, we generated 2D finite-difference elastic wave synthetics and from them calculated receiver functions and CCP stacks. We compare the observations with synthetic sections that have been spatially sampled at 0.25 km to 40 km. The densely sampled synthetics show that several events in the field data that were originally interpreted as the Moho are multiple reflections within sedimentary basins. Where the Moho has the steepest dip under the plate boundary the CCP stacks fail to image the Moho well, regardless of the density of spatial sampling. A suitable spatial sampling criterion for clearly imaging the lower crust and Moho is to overlap Fresnel zones by 50% at Moho depth, which for the 1 Hz receiver functions examined here, requires an instrument spacing of 15-20 km, with the actual field data density ranging from 20 km to 100 km.

关键词： receiver function CCP stacking finite-difference modeling BOLIVAR project Fresnel zone

THE RESPONSE OF SUMMER DRYNESS/WETNESS PROBABILITY IN NORTH CHINA TO GLOBAL WARMING

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Acta meteorologica Sinica 1994年第1期8卷 41-50页

作者：黄嘉佑 department of geophysics Peking UniversityBeijing 100871

Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been *** temporal and spatial char- acteristics for the series of WP in the stations are extracted by using empirical orthogonal functions(EOFs).The spatial patterns show that the dryness/wetness variations in the stations in the area are consistent with each other and its main characteristics can be represented by the WP series in Beijing. Having analysed the WP series of 120 years(1870—1989)in Beijing,the results show that the dry tendency has a re- sponse to the global *** variation of the dryness/wetness in the stations is associated with the temperature variation in the Northern *** relation is *** degree of the reliance is associated with the century variation of the temperature.

关键词： wetness probability persistence probability empirical orthogonal functions(EOFs) correlation moment

SIGNAL DETECTION OF GLOBAL CLIMATE CHANGE AND EXTERNAL FORCING FACTORS

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Acta meteorologica Sinica 2001年第4期15卷 397-406页

作者：李晓东王在文侯章栓 department of geophysics Peking UniversityBeijing 100871

In this paper,we displayed one-dimensional climate signals,such as global temperature variation,Southern Oscillation Index and variation of external forcing factors,on a two- dimensional time-scale plane using compactly supported wavelet *** the lag- correlation analysis method,and interpretative variance analysis method,and phase comparison method to the wavelet analysis result,we not only gained the variation on different scales to the global temperature and El Nino signals,the location of the jump point and intrinsic scale of these series,but also indicated the magnitude,extent and time of the effect of external forcing factors on *** also put forward reasonable explanation to the main variation of recent 140 years.

关键词： climate change signal detection compactly supported B-spline wavelet analysis jump point intrinsic scale

EXPERIMENTAL RESEARCH ON NONLINEAR LANDAU DAMPING OF ION ACOUSTIC WAVES

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Chinese Science Bulletin 1990年第24期35卷 2035-2039页

作者：王文清 department of geophysics Peking University Bering 100871 PRC

Nonlinear Landau damping of an electron or ion wave is one of the most important nonlinear phenomena in plasma experiments. In 1965 O’ Neil, Al’tshul and Karpaman predicted theoretically that the amplitude decay of the electron or ion wave in space is not exponential, as predicted by linear theory, if the amplitude is large. In 1972 R. N. Franklin et al. measured the amplitude profile of the nonlinear electron plasma wave (EPW) at 38 MHz, and the profile showed a nonmonotonic decay. These oscillations in amplitude were exactly what had been expected from the nonlinear effect of trapped electrons. They verified experimentally the existence of the nonlinear Landau damping of the EPW.

关键词： ion acoustic wave trapped electrons nonlinear Landau damping.

VISIBILITY AND TELEPHOTOMETER

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Advances in Atmospheric Sciences 1985年第1期2卷 124-128页

作者：毛节泰李建国 Beijing department of geophysics Peking University

This paper discusses the possible error of the calculation of the atmospheric extinction coefficient by the Koschmieder visibility formula. An analysis of the problem shows that an error of 10% can be introduced in the measurement if the target used is a non-blackbody. By using the telephotometer as a tool of measurement, such an error can be markedly reduced.

关键词： VISIBILITY AND TELEPHOTOMETER

Groundwater Potential Evaluation in a Typical Basement Complex Environment Using GRT Index—A Case Study of Ipinsa-Okeodu Area, near Akure, Nigeria

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Journal of Geoscience and Environment Protection 2017年第3期5卷 240-251页

作者： Igbagbo A. Adeyemo Gabriel O. Omosuyi Bosede T. Ojo Abiola Adekunle department of applied geophysics Federal University of Technology Akure Nigeria

This study is aimed at evaluating groundwater potential of Ipinsa-Okeodu area, near Akure, Southwestern Nigeria. A multi-criteria model was developed for achieving this aim;the GRT model which is based on geology of each sounding point, resistivity, and thickness of the aquifer across the study area was successfully used to evaluate the aquifer potential of the area for future groundwater development programme in the area. Geophysical investigation involving vertical electrical sounding was carried out across the study area. A total of one hundred and two (102) vertical electrical soundings (VES) data were acquired using Schlumberger array with maximum half-current electrode separation of 150 m. Three to five geoelectric layers were delineated across the study area. The predominant curve types are KH, H, K and A. The maps of aquifer layer resistivity and aquifer layer thickness were generated and synthesized with the geology of the study area in producing the GRT model map/groundwater potential map. The groundwater potential map shows that the area is characterized by five groundwater potential zones;poor, low, moderate, good and high. The northwestern regions, north central and part of the southwestern regions are high groundwater potential zones, the northern and most part of southeastern zone are of moderate potential, while small portion in the southeastern and northern zones are of low groundwater potential.

关键词： GRT-Model Groundwater Potential Evaluation Geology Resistivity Thickness

Thermal history of a Late Mesoproterozoic paired metamorphic belt(?)during Rodinia assembly:New insight from medium-pressure granulites from the Aravalli-Delhi Mobile Belt, Northwestern India

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Geoscience Frontiers 2018年第2期9卷 335-354页

作者： Santanu Kumar Bhowmik Somnath Dasgupta Sudipta Baruah Deepika Kalita department of Geology and geophysics Indian Institute of Technology Kharagpur department of Geography Faculty of Natural SciencesJamia Millia Islamia

In this study, we investigate the possible record of a Late Mesoproterozoic paired metamorphic belt in the Aravalli-Delhi Mobile Belt(ADMB), NW India using a suite of supracrustal and metaigneous granulites from the Pilwa-Chinwali granulite terrain at the north-western margin of the ADMB. Using metamorphic reaction textures, mineral chemistry, metamorphic reaction history, geothermobarometric computations and electron microprobe dating of monazite in 5 samples of pelitic granulite, leptynite gneiss, enderbite and charnockite, we have deduced a medium-pressure granulite facies metamorphism(P between 4.9 and 6.8 kbar, T> 760-815℃) along a heating-cooling, counterclockwise P-T path between 1.09 and 1.01 Ga. When collated with published metamorphic and chronological constraints and geological settings of the adjoining crustal domains of the ADMB, these findings provide new insights into the developments of two tectonic domains of contrasting thermal gradients at ca. 1.0 Ga, consistent with metamorphic transformations in tectonically thickened middle-lower crustal sections during continental collision to continental subduction and in the root zones of spatially adjacent island arc, as part of the Rodinia supercontinent assembly event.

关键词： ADMB Granulites CCW-P-T path Monazite chemical dating ca. 1.0 Ga metamorphism Paired metamorphic belt

Application of Cross-Plotting Techniques for Delineation of Coal and Non-Coal Litho-Units from Well Logs

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Geomaterials 2012年第4期2卷 94-104页

作者： Rima Chatterjee Suman Paul department of applied geophysics Indian School of Mines Dhanbad India

Well log responses can be used to delineate coal and carbonaceous shale from other non-potential litho-units by cross-plotting technique. The cross-plotting between gamma ray and density had been carried out for 15 wells of Jharia coalfield, India. Through these different cross-plots across the study area, different litho-units like;coal, shaly coal, carbonaceous shale, shale, sand/sandstone, shaly sand, jhama and igneous intrusion (mica peridotite) have been identified. Clustering of points for different lithologies in the above cross-plots indicate that the different trends with marginal overlap between carbonaceous shale/shaly coal and shale as well as shaly sand and shale. The coal horizons are mostly overlain and underlain by shale or sandstone. Cross-plot analysis indicates the various coal lithologies which will play important role in CBM exploration and exploitation strategy.

关键词： Jharia Coalfield Cross-Plot P-Wave Impedance CBM Reservoir