SOME NEW UNDERSTANDINGS OF LAND-SURFACE PROCESSES IN ARID AREA FROM THE HEIFE^*          下载免费PDF全文

Hu Yinqiao  Gao Youxi 《Acta Meteorologica Sinica》1996,10(2):233-246

The survey for the HEIFE(Atmosphere-Land Surface Processes Experiment at Heihe River Basin,Western China) is given in the paper.The following basic subjects for land-surface processes in arid areas are studied:(1) the general characteristics of the energy budget on ground surface in arid areas;(2) the parameterization of the land surface processes;(3) the interaction between oasis and its desert circumstances,a special phenomenon in arid areas.The analysis shows that the sensible heat flux in the surface energy budget is in the majority,and the latent heat flux may be neglected.The influence of atmospheric stratification stability on the turbulent transfer of energy and substance must be considered in parameterization of land surface processes in arid areas.The "cold island effect" phenomenon in oasis and the "humidity inversion" phenomenon in desert near oasis are the result of the interaction between them.The results would improve the understanding of land surface processes in arid areas.  相似文献   

有限不等厚介质中主层褶皱的模拟实验及理论研究   总被引：3，自引：0，他引：3       下载免费PDF全文

叶柏龙  何绍勋 《地球科学》1993,18(2):159-167

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中国南北带地壳上地幔三维面波速度结构和各向异性   总被引：6，自引：1，他引：5       下载免费PDF全文

陈立华  庄真 《地球物理学报》1992,35(5):574-583

本文用长周期763地震仪面波群速度资料反演了中国南北带及邻区的三维速度结构.其中采集238条瑞利波和358条勒夫波混合频散曲线,使用均等显示滤波方法,并以4°×4°为一格将我国境内分为147格.用随机逆反演方法得到了研究区16格的纯路径频散.面波速度结构及演结果表明:1.莫霍界面深度一般在40-50km之间,最深达65km.总趋势是从东到西加深,且在南北带西侧南北两端向中部明显加深,东侧变化小.2.地幔顶部普遍出现很厚的低速层,上界面一般埋深60-80km.上地幔顶盖厚度一般为20-60km,速度为4.30-4.50km/s.3.研究区普遍存在各向异性,而且勒夫波和瑞利波速度的差值(V_SV-V_SH)的绝对值随深度有增大的特点,在南北带南部和西北部V_SV-V_SH各向异性现象更为明显.  相似文献   

The Tornquist Zone, a north east inclining lithospheric transition at the south western margin of the Baltic Shield: Revealed through a nonlinear teleseismic tomographic inversion     

P. Voss  K. Mosegaard  S. Gregersen  TOR Working Group 《Tectonophysics》2006,416(1-4):151

From July 1996 to August 1997 the TOR project operated 130 seismographs in North Germany, Denmark and South Sweden, with the aim of collecting signals from local, regional and teleseismic earthquakes. This data set is particularly interesting since the seismic antenna crosses the most significant geological boundary in Europe, the Tornquist Zone, which in the northern part is the border between the Baltic Shield and the younger European lithosphere. Previous studies have shown significant physical changes in the crust and upper mantle across this transition zone, including two independent teleseismic tomographic studies of the TOR data set. But these two studies disagree on the orientation of the slope of the transition. Both studies used an iterative linearized inversion method. We will in this work Preprint submitted to Elsevier Science 27 July 2005 present an inversion based on Bayesian statistics, where the solution space is examined in order to study a very large number of tomographic solutions and to examine the solution uniqueness and uncertainty. The method is applied to measurements of 3345 relative teleseismic P-phase travel times from 48 teleseismic earthquakes with good azimuthal coverage with respect to the great circle arc of the TOR array. We find the lithospheric transition to be a north east inclination of around 30° to 45° off vertical.  相似文献   

Time domain Gauss–Newton seismic waveform inversion in elastic media     

Dong-Hoon Sheen  Kagan Tuncay  Chang-Eob Baag  Peter J. Ortoleva 《Geophysical Journal International》2006,167(3):1373-1384

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New results on the resistivity structure of Merapi Volcano (Indonesia), derived from three-dimensional restricted inversion of long-offset transient electromagnetic data     

Michael Commer  Stefan L. Helwig  reas Hördt  Carsten Scholl  Bülent Tezkan 《Geophysical Journal International》2006,167(3):1172-1187

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Fault plane orientations of small earthquakes of the 1997 Umbria-Marche (Italy) seismic sequence from P-wave polarities and rise times     

Marilena Filippucci  Salvatore de Lorenzo  Enzo Boschi 《Geophysical Journal International》2006,166(1):322-338

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Strain partitioning and stress rotation at the North Anatolian fault zone from aftershock focal mechanisms of the 1999 Izmit M_w= 7.4 earthquake     

Marco Bohnhoff  Helmut Grosser  Georg Dresen 《Geophysical Journal International》2006,166(1):373-385

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Fault slip and rupture velocity inversion by isochrone backprojection     

Gaetano Festa  Aldo Zollo 《Geophysical Journal International》2006,166(2):745-756

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3D behaviour of contamination in landfill sites using 2D resistivity/IP imaging: case studies in Portugal   总被引：2，自引：0，他引：2  

E. Martinho  F. Almeida 《Environmental Geology》2006,49(7):1071-1078

Aiming at defining a valid spatial contamination model, resistivity and induced polarization (IP) measurements were used to investigate contamination plumes in the vicinity of two municipal landfills (Ovar and ílhavo). Previous geophysical surveys and underground water samples confirmed the contamination. However 2D resistivity/IP surveys enabled in obtaining a more accurate spatial model. The Ovar survey consisted of two profiles with nine Wenner soundings each; the ílhavo survey was carried out along two individual lines using a Wenner standard pseudo-section. In both situations, negative IP values were found associated with positive IP values, which can be explained mainly by 2D or 3D geometric effects caused by the presence of the conductive plumes. The data were modelled using a 2D inversion program (RES2DINV) and the resulting resistivity and chargeability distributions were displayed as pseudo-sections. The resistivity and chargeability pseudo-sections define the contamination plumes and the sedimentary structure. These case studies illustrate the advantages of 2D resistivity/IP surveys for the mapping of shape and dimension of contamination associated with landfills.  相似文献