区域经济联系定量分析初探：以上海与苏锡常地区经济联系为例   总被引：49，自引：2，他引：49  

王德忠  庄仁兴 《地理科学》1996,16(1):51-57

针对目前区域联合日益广泛和经济联系量化研究不足的现状，在联系强度等方面提出一些新概念；阐述了经济联系量化指标的选取，建立了经济联系定量分析模型。  相似文献   

Seismic Ground Motion Expected for the Eastern District of Naples     

C. Nunziata  F. Vaccari  G.F. Panza  G. Luongo  D. FÄH 《Natural Hazards》1997,15(2-3):183-197

The seismic ground motion of a test area in the eastern district of Naples is computed with a hybrid technique based on the mode summation and the finite difference methods. This technique allows us the realistic modelling of source and propagation effects, including local soil conditions. In the modelling, we consider the 1980 Irpinia earthquake, a good example of strong shaking for the area of Naples, which is located about 90 km from the epicenter.The detailed geological setting is reconstructed from a large number of drillings. The sub-soil is mainly formed by alluvial (ash, stratified sand and peat) and pyroclastic materials overlying a pyroclastic rock (yellow neapolitan tuff), representing the neapolitan bedrock. The detailed information available on mechanical properties of the sub-soil and its geometry warrants the application of the sophisticated hybrid technique.As expected, the sedimentary cover causes an increase of the signal's amplitudes and duration. If thin peat layers are present, the amplification effects are reduced, and the peak ground accelerations are similar to those observed for the bedrock model. This can be explained by the backscattering of wave energy at such layers, that tend to seismically decouple the upper from the lower part of the structure.For SH-waves, the influence of the variations of the S-wave velocities on the spectral amplification is studied, by considering locally measured velocities and values determined from near-by down-hole measurements. The comparison between the computed spectral amplifications confirms the key role of an accurate determination of the seismic velocities of the different layers.The comparison performed between a realistic 2-D seismic response and a standard 1-D response, based on the vertical propagation of waves in a plane layered structure, shows considerable difference, from which it is evident that serious caution must be taken in the modelling of expected ground motion at a specific site.  相似文献   

Optimal weighting in the finite difference solution of the convection-dispersion equation     

H. Q. Wang  M. Lacroix 《Journal of Hydrology》1997,200(1-4):228-242

Oscillation and numerical dispersion limit the reliability of numerical solutions of the convection-dispersion equation when finite difference methods are used. To eliminate oscillation and reduce the numerical dispersion, an optimal upstream weighting with finite differences is proposed. The optimal values of upstream weighting coefficients numerically obtained are a function of the mesh Peclet number used. The accuracy of the proposed numerical method is tested against two classical problems for which analytical solutions exist. The comparison of the numerical results obtained with different numerical schemes and those obtained by the analytical solutions demonstrates the possibility of a real gain in precision using the proposed optimal weighting method. This gain in precision is verified by interpreting a tracer experiment performed in a laboratory column.  相似文献   

Study on simulation of spatial correlative earthquake ground motion field     

Xiao-Jun Li  Feng-Xin Zhao  Yu-Xian Hu 《地震学报(英文版)》1997,10(2):267-271

  相似文献   

VARIATION OF TOTAL OZONE IN LOWER LATITUDE AREA OF CHINA     

张秀年  常有礼  陈辉  郭世昌  孙正友 《热带气象学报(英文版)》2004,10(2):171-177

By using the observational O3 data of Kunming and Hong Kong during the period of 1997 – 2001, the paper studies the distribution and variation of total ozone in low latitude region of China. The study shows that the characteristics of variation in Kunm…  相似文献   

Estimation of Regional Evapotranspiration by Combining Aircraftand Ground-Based Measurements     

P. R. Isaac  R. Leuning  J. M. Hacker  H. A. Cleugh  P. A. Coppin  O. T. Denmead  M. R. Raupach 《Boundary-Layer Meteorology》2004,110(1):69-98

Two methods are examined for combining measurements from instrumented aircraftand towers to estimate regional scale evapotranspiration. Aircraft data provided spatially averaged values of properties of the surface, the evaporative fraction and maximum stomatal conductance. These quantities are less sensitive to meteorological conditions than the turbulent fluxes of heat and water vapour themselves. The methods allowed aircraft data collected over several days to be averaged and thus to reduce the random error associated with the temporal under-sampling inherent in aircraft measurements. Evaporative fraction is estimated directly from the aircraft data, while maximum stomatal conductance is estimated by coupling the Penman–Monteith equation to a simple model relating surface conductance to the incoming shortwave radiation and specific humidity saturation deficit. The spatial averages of evaporative fraction and maximum stomatal conductance can then be used with routine tower data to estimate the regional scale evapotranspiration. Data from aircraft flights and six ground based sites during the OASIS field campaign in south–east New South Wales in 1995 have been used to check the methods. Both the evaporative fraction and the maximum stomatal conductance derived from the aircraft data give information on the spatial variability of the surface energy budget at scales from 10 to 100 km. Daily averaged latent heat fluxes estimated using these methods for the OASIS study region agree with the available observations in quasi-stationary conditions or in weakly non-stationary conditions when the data from several aircraft flights are averaged to reduce the impact of short term imbalances in the surface energy budget.  相似文献   

巴楚-伽师Ms6.8地震地磁异常特点分析     

朱燕 《内陆地震》2004,18(2):162-168

通过分析、比较1996--2003年喀什地震台站记录到的新疆伽师及附近地区发生的多次6级地震的地磁前兆异常特征，发现在这几组地震活动过程中喀什地震台的地磁表现出不同的异常特征，说明与地震破裂特征有更深层次的相关性，且地磁响应比异常和总强度差值异常在一定程度上反映了台站周围小范围的震源区介质电性结构的变化。巴楚-伽师6．8级地震前地磁异常特征并不十分突出，有别于1996—1998年伽师强震群震前地磁异常量较丰富的特点。  相似文献   

Numerical Studies with a Regional Atmospheric Climate Model Based on Changes in the Roughness Length for Momentum and Heat Over Antarctica     

C. H. Reijmer  E. Van Meijgaard  M. R. Van Den Broeke 《Boundary-Layer Meteorology》2004,111(2):313-337

A regional atmospheric climate model is used toexamine the effect of changes in the roughnesslengths of momentum (_z0m) and heat (_z0h)on the structure of the lower atmosphere and on thesurface energy fluxes over Antarctica. Fourexperiments were carried out in which _z0mand/or _z0h were altered with respect to acontrol experiment. The changes consisted of (1) alowering of _z0m from a field aggregated froma vegetation map with an orographic correction basedon the European Centre for Medium-Range WeatherForecasts _z0m field, to a constant value of10^-3 m; and (2) a lowering of _z0h from a valueequal to _z0m to a constant value of 10^-3 mor a value dependent on the wind speed via a surfacerenewal model. A reduction of _z0m results in theexpected increase in near-surface wind speed. It alsoresults in an increase in the depth of the layer in whichsouth-easterly near-surface winds prevail, and in adecrease in the strength of the large-scale flow overthe continent, in particular in summer. In theescarpment region a decrease of _z0m is foundto result in too high wind speeds. Surface temperatureson average decrease while atmospheric temperaturesincrease, resulting in an increase of near-surfacestatic stability. Changes in roughness lengths donot significantly change the temperature profiles.The surface fluxes, on average found reduced, aremodelled best by using the _z0h based on thesurface renewal method.  相似文献   

兰州CAWS600-R自动站与人工观测资料对比分析   总被引：7，自引：10，他引：7  

王宝鉴陈旭辉  陶健红陆登荣 《气象科技》2004,32(4):281-285290

利用2002年11月到2003年2月兰州CAWS600-R型自动站与人工观测的温度、本站气压、水汽压、相对湿度、5～320cm地温等资料，分析了对比观测资料的差值。结果表明：对气温、本站气压、水汽压、相对湿度及320cm地温等要素观测误差较小，5～160cm地温的观测误差较大。自动观测仪器的系统性偏差、测量元件的精度及对气象要素变化响应的灵敏度、观测时间的差异和人为因素的影响是造成对比观测误差的原因。  相似文献   

RGMAP系统在1：5万区调中的应用   总被引：1，自引：0，他引：1  

方成名葛梦春  张雄华王庆明 《新疆地质》2004,22(1):98-100

根据RGMAP系统在崇阳县幅1：5万区调过程中的应用实践．阐述了数字区调过程中的数字路线、数字实测剖面数据采集以及室内数据整理、地质图编稿和专题图件制作的工作流程和方法，在此基础上对RGMAP综合应用进行了展望．  相似文献