北京地区大气稳定度垂直分布特征   总被引：7，自引：3，他引：7  

毕雪岩  刘烽  陈辉  吴兑  邓雪娇  黄健 《热带气象学报》2003,19(Z1):173-179

基于北京325米气象铁塔观测资料,分析了北京地区大气稳定度垂直分布特征、日变化特征、季节变化特征.  相似文献   

利用洞穴石笋的δ~(18)O和δ~(13)C重建3000a以来北京地区古气候和古环境——石花洞研究系列之三   总被引：10，自引：0，他引：10       下载免费PDF全文

李红春  顾德隆  陈文寄  李铁英 《地震地质》1997,(1)

首次提出用石笋中稳定同位素记录重建由降雨量和降水气团同位素组成所反映的古气候历史，从而为研究高分辨率的古季风气候信息开辟了新的途径。利用Ｈｅｎｄｙ准则、洞穴温度、研究区水系的δ１８ＯＨ２Ｏ值以及温度公式，证实了同位素分析结果的可靠性，ＣａＣＯ３－Ｈ２Ｏ之间存在同位素平衡分馏。对采自石花洞的石笋样品进行了分辨率约为２５ａ的δ１８Ｏ和δ１３Ｃ的分析测量，从而得到３０００ａ以来，北京地区古气候和古环境的变化信息  相似文献   

北京地区末次冰消期气候环境变化记录的初步研究   总被引：4，自引：0，他引：4       下载免费PDF全文

魏兰英  彭贵  严富华  尹金辉  卢演俦 《第四纪研究》1997,17(2):88-191

对北京房山县长沟镇附近埋藏末次冰消期湖沼沉积物层序和岩性变化的观测资料，以及１４Ｃ测年、孢粉分析、磁化率、有机碳δ^１３Ｃ值和有机质含量等测定资料的综合研究表明：１)约１３０００ａＢ．Ｐ．以前本区气候相当干冷，植被稀疏；２)约１３０００～１２１００ａＢ．Ｐ．气候明显变暖，植被日趋繁茂，出现针叶－落叶阔叶林；３)约１２１００～１００００ａＢ．Ｐ．气候波动相当显著，十分不稳定，并在约１１６００～１１３００ａＢ．Ｐ．和约１０９５０～１０４８０ａＢ．Ｐ．气候明显向干冷逆转；而在这两个气候逆转之间出现相对湿润或温湿的气候。这一短期气候变化与北大西洋地区有相似之处，又有差异。  相似文献   

北京西山地面塌陷的形成因素浅析     

单青生 《城市地质》1996,8(2):1-10

地下采矿是地面塌陷失决条件，自然重力及其他外界触发因素是其发展动因，地面塌陷受覆岩时代及岩性，采空区尺寸大小，煤层倾角，煤层厚度及开采深度，重复采动，水文条件变化，地形地势和松散盖层的影响。  相似文献   

京津唐地区深部挤压带特征及其与地震的关系     

张加桂 《地质通报》1997,(2)

京津唐地区的深部挤压带轴线沿宁河、香河、昌平一线呈南东—北西走向，在通过该带的北东向Ｍ和Ｃ面上均有一向北西弯曲的弧形。地壳下部和上地幔顶部层位呈透镜状增厚，浅部的北东向断裂也向北西弯曲。应力测量表明现今该带的应力场为向北西挤压。深部挤压作用是由渤海底部的扩张所产生的。该挤压带控制着地震的发生，特别其北东侧是一个强地震区  相似文献   

Estimation of Site Effects in Beijing City   总被引：6，自引：0，他引：6  

Z. Ding  Y. T. Chen  G. F. Panza 《Pure and Applied Geophysics》2004,161(5-6):1107-1123

— For the realistic modeling of the seismic ground motion in lateral heterogeneous anelastic media, the database of 3-D geophysical structures for Beijing City has been built up to model the seismic ground motion in the City, caused by the 1976 Tangshan and the 1998 Zhangbei earthquakes. The hybrid method, which combines the modal summation and the finite-difference algorithms, is used in the simulation. The modeling of the seismic ground motion, for both the Tangshan and the Zhangbei earthquakes, shows that the thick Quaternary sedimentary cover amplifies the peak values and increases the duration of the seismic ground motion in the northwestern part of the City. Therefore the thickness of the Quaternary sediments in Beijing City is the key factor controling the local ground effects. Four zones are defined on the base of the different thickness of the Quaternary sediments. The response spectra for each zone are computed, indicating that peak spectral values as high as 0.1 g are compatible with past seismicity and can be well exceeded if an event similar to the 1697 Sanhe-Pinggu occurs.  相似文献   

北京怀柔长园花岗杂岩体岩石学和构造变形特征及其地质意义   总被引：1，自引：3，他引：1  

姬广义  汪洋  夏希凡 《城市地质》2004,16(4):1-13

本文描述北京北部燕山地区怀柔长园杂岩体及围岩构造变形迹象 ,并对其成因进行了初步分析。认为中、晚侏罗世时期构造应力场的变化是杂岩体内岩石构造变形的主要因素 ,并以此为根据为该地区燕山期构造 岩浆事件序列的建立提供部分证据。  相似文献   

北京延庆北部地区后城组火山岩岩石化学特征与成因探讨   总被引：3，自引：0，他引：3  

汪洋  姬广义 《城市地质》2004,16(1):16-25

根据TAS图解 ,北京延庆北部地区后城组火山属于玄武粗安岩 流纹岩 (和粗面岩 )的双峰式组合。该套火山岩不属于典型的钾玄岩系列 ,在基性岩和中性岩中总体上以碱性系列和向碱性系列过渡的高钾钙碱性系列、钾玄岩系列为主 ,流纹岩类属于富钾质的拉斑系列。该套火山岩轻稀土元素明显富集。玄武粗安岩类岩石没有负铕异常或负铕异常不明显 ,而流纹岩存在明显的负铕异常。延庆北部地区后城组火山岩形成于燕山运动早期或中期阶段的造山变形事件趋于结束时的后碰撞构造环境中。  相似文献   

Numerical Simulation of Wind and Temperature Fields over Beijing Area in Summer   总被引：4，自引：0，他引：4  

HU Xiaoming  LIU Shuhu  WANG Yingchun  LI Ju 《Acta Meteorologica Sinica》2005,19(1):120-127

1. IntroductionThe basic role of urban-rural boundary layer re-search is to study all kinds of physical process changesin the atmosphere boundary layer over urban and itssurrounding areas. Urban heat island (UHI) is a well-known feature of urban-rural climate. Attempts toincrease the understanding of the causes of the UHIand other urban-rural boundary layer phenomena haveused observational, theoretical and modelling methodssince long before. Seaman (1989) used a hydrostaticmodel, with real …  相似文献   

Changes in the spatial scale of Beijing UHI and urban development   总被引：2，自引：1，他引：2  

YU Shuqiu  BIAN Lingen  LIN Xuechun 《中国科学D辑(英文版)》2005,48(Z2)

The seasonal and interannual variations of Beijing urban heat island (UHI) are investigated in this paper using the temperature data from 1960 to 2000 at 20 meteorological stations in the Beijing region, and then the relationship between the intensity and spatial scale of UHI and Beijing urbanization indices is analyzed and discussed. Main conclusions are the followings. First, Beijing UHI shows obvious seasonal variations, and it is strongest in winter, next in spring and autumn, and least in summer. The seasonal variation of the UHI mainly occurs in the urban area. The UHI intensity at the center of Beijing is more than 0.8℃ in winter, and only 0.5℃ in summer. Second, the intensity of Beijing HUI exhibits a clear interannual warming trend with its mean growth rate (MGR) being 0.3088℃/10 a. The MGR of HUI is largest in winter, next in spring and autumn, and least in summer, and the urban temperature increase makes a major contribution to the growth of HUI intensity. Third, since the Reform and Opening, the urbanization indices have grown several ten times or even one hundred times, the intensity of HUI has increased dramatically, and its spatial scale also expanded distinctively along with the expansion of urban architectural complexes. Fourth, the interannual variation of urbanization indices is very similar with that of HUI intensity, and their linear correlation coefficients are significant at a more than 0.001 confidence level.  相似文献