TOVS/MSU-ch.2亮温的中尺度天气特征环境          下载免费PDF全文

韩卫清  王宗皓 《应用气象学报》1994,5(2):242-247

将NOAA-11探测仪TOVS/MSU-ch.2亮温，对照分析四川省（20°—40°N，90°—110°E）境内1989年7月7日至12日几次重复出现的中尺度云团发展和降水过程，得到两点看法:①MSU-ch.2亮温可能表示700 hPa附近中尺度天气的一种特征环境；②强中尺度对流云团可能在MSU-ch.2亮温分布的相对低值到高值过渡带内强烈发展，有时偏向高值区出现降水天气。  相似文献   

软弱破碎围岩变形特性   总被引：4，自引：0，他引：4  

李守柱  黄鼎成 《工程地质学报》1993,1(1):74-84

本文在连续十余年原位监测试验资料的基础上,描述了全断面开挖的软弱围岩变形u-t全过程曲线;阐明了不同变形阶段的变形速率、变形量以及这些变形的时空效应;探讨了岩体工程地质特性、埋深、洞径、开挖方式和支护及时性等主要因素对围岩变形特性的影响;并针对具体工程提出了围岩稳定性状态划分及其判别标准、失稳险情预报原则、变形控制标准与初期支护抗力的确定原则、后期支护最佳施作时期的选择以及合理开挖方式。  相似文献   

510—1铀矿床构造、地球化学特征及其成因探讨     

徐光请 《甘肃地质》1993,2(1):54-63

本文根据510—1铀矿床形成的构造条件和地球化学特征,认为该富铀矿床的成因是地洼阶段壳幔混合型深源热液上升侵位,与贡巴—益哇逆冲推覆构造上盘中、下志留统羊肠沟组硅灰岩含水含矿层屏蔽构造相结合的结果。并指出古今统一的四维空间屏蔽构造是找矿的方向。  相似文献   

Characteristic frequencies for earthquake families and their tectonic implications: Evidence from earthquake swarms in the kanto district,Japan     

Masaru Tsujiura 《Pure and Applied Geophysics》1983,121(4):573-600

Through the analyses of waveform and spectrum for two swarm sequences in the Kanto District, including the results from 15 earthquake swarsm obtained previously, the mechanism of the faulting process in earthquake swarms is clarified in more detail. Earthquakes occurring in short time intervals consist mainly of events with similar waveforms andS-P times. These are called “earthquake families,” and many families are observed during a swarm sequence (70–80 percent); for example, 15 families were observed in the 1983 Izu Peninsula earthquake swarm. The source spectra of earthquake families share the same corner frequency, even though their low-frequency levels may differ by a factor as great as 1000, and the value of the corner frequency depends on the size of the largest event in the family. Local variations of corner frequencies within a factor of 25 are found among the earthquake swarms in the Kanto District. These observations suggest the existence of a characteristic fault length depending on the swarm area, and its length may be responsible for the size of the largest event in the family. The characteristic fault length is about 100 m for Ashio, about 400 m for the Izu Peninsula and about 2.5 km for areas off the Chiba Prefecture, and the magnitudes of the largest events expected from these fault lengths are about 2.5, 4, and 6, respectively.  相似文献   

朝阳地震台地下流体数字化资料图象特征初探     

杨玉光  金众范  孔德民 《东北地震研究》2004,20(4):57-63

本文分析了朝阳地震台数字水化资料9种类型数据图象，并对图象的特征及其在地震预报中应用等问题进行了探讨。  相似文献   

Theoretical investigation of convective instability in inclined and fluid-saturated three-dimensional fault zones   总被引：2，自引：0，他引：2  

Chongbin Zhao  B.E. Hobbs  A. Ord  Shenglin Peng  H.B. Mühlhaus  Liangming Liu 《Tectonophysics》2004,387(1-4):47-64

The convective instability of pore-fluid flow in inclined and fluid-saturated three-dimensional fault zones has been theoretically investigated in this paper. Due to the consideration of the inclined three-dimensional fault zone with any values of the inclined angle, it is impossible to use the conventional linear stability analysis method for deriving the critical condition (i.e., the critical Rayleigh number) which can be used to investigate the convective instability of the pore-fluid flow in an inclined three-dimensional fault zone system. To overcome this mathematical difficulty, a combination of the variable separation method and the integration elimination method has been used to derive the characteristic equation, which depends on the Rayleigh number and the inclined angle of the inclined three-dimensional fault zone. Using this characteristic equation, the critical Rayleigh number of the system can be numerically found as a function of the inclined angle of the three-dimensional fault zone. For a vertically oriented three-dimensional fault zone system, the critical Rayleigh number of the system can be explicitly derived from the characteristic equation. Comparison of the resulting critical Rayleigh number of the system with that previously derived in a vertically oriented one has demonstrated that the characteristic equation of the Rayleigh number is correct and useful for investigating the convective instability of pore-fluid flow in the inclined three-dimensional fault zone system. The related numerical results from this investigation have indicated that: (1) the convective pore-fluid flow may take place in the inclined three-dimensional fault zone; (2) if the height of the fault zone is used as the characteristic length of the system, a decrease in the inclined angle of the inclined fault zone stabilizes the three-dimensional fundamental convective flow in the inclined three-dimensional fault zone system; (3) if the thickness of the stratum is used as the characteristic length of the system, a decrease in the inclined angle of the inclined fault zone destabilizes the three-dimensional fundamental convective flow in the inclined three-dimensional fault zone system; and that (4) the shape of the inclined three-dimensional fault zone may affect the convective instability of pore-fluid flow in the system.  相似文献   

蒙古和新疆亚板块强震时空演化特征     

陈立德  付虹  邬成栋 《内陆地震》2006,20(4):289-295

蒙古亚板块区的强震活动,在时间序列上可划分为4个活跃期3个平静期。活跃期频度低(平均2次),强度大(最大震级7.9~8.0级),持续时间涨落大(最短1年,最长14年,平均7年);平静期相对稳定,持续时间22~25年。空间演化方面具有阿尔泰山地震带与杭爱山地震区之间交替活动,阿尔泰山地震带内中、南、北段相互迁移的特征。新疆亚板块区的强震活动,在时间序列上可划分为5个活跃期4个平静期,活跃期有强弱之分并呈现交替特征,强活跃期持续时间长(13年),频度高(7~8次),强度大(最大7.5~8.3级),而弱活跃期则相反。在空间演化上相邻活跃期除主体活动区外,还有参与活动区,主体活动区在天山区与兴都库什区之间交替出现。  相似文献   

夏季南亚高压年际变化的特征时间尺度及其时空演变     

尤卫红  段长春  赵宁坤  马振锋 《高原气象》2006,25(4):601-608

应用三维数据的时间小波变换方法,分析了夏季南亚高压年际变化的特征时间尺度及其时空演变。结果表明:夏季南亚高压年际变化的特征时间尺度分别约为2,5,10年和更长的时间尺度。2,5,10年特征尺度的较大振幅能量活动区主要位于20°N以南、35°N以南和15°~35°N之间,其中5年特征尺度的最大中心位于青藏高原上空32.5°N,92.5°E附近,10年特征尺度的最大中心则位于青藏高原东侧27.5°N,110°E附近。与5年特征尺度相对应的最大振幅能量活动中心纬度的位势高度值表现出了明显的东西向波动的时间演变特征,与10年特征尺度相对应的最大振幅能量活动中心纬度的位势高度值变化则表现出了向东移动趋势的时间演变特征。与5年和10年特征尺度相对应的最大振幅能量活动中心经度的位势高度值变化则表现出了一种明显向北移动的时间演变趋势。  相似文献   

青海强震等间距特征研究及未来强震趋势预测   总被引：5，自引：0，他引：5  

张晓东  张雅玲 《中国地震》1998,14(1):59-67

利用塑性力学和地震力学以及前人的研究结果,提出了一种新的地震等间距特征机理的解释方法,认为地夺等间距特征的成因是中、下地壳的滑移网同上部地壳的相互作用。其动力源为环太平洋地震带和欧亚地震带的联合作用。利用青海强震分布的等间跨特征对未来可能发生强震的地点进行趋势预测。  相似文献   

长春市城区大气污染特征研究   总被引：6，自引：1，他引：5  

李文波 《地理科学》1998,18(1):80-80

研究了长春市地貌景观的变化,并以空气污染气象学为指导,重点探讨了由于城区粗糙度的变化,导致大气边界层的改变,从而形成了城市区域特殊的温度和风场。出现了城市热岛和“静风”下的环流现象,改变了城区各部分大气环境质量。局部地区呈现出污染加重的趋势。为今后制定城市发展规划,防治大气污染提供了科学依据和对策。  相似文献