切变基流中赤道Rossby包络孤立波(英文)     

赵强  付遵涛  刘式适 《大气科学进展》2001,(3)

利用一个简单的赤道β平面浅水模式和多尺度摄动法，从描写赤道Ｒｏｓｓｂｙ波的正压大气位涡度方程中推导出在切变基本维向流中赤道Ｒｏｓｓｂｙ波包演变所满足的非线性Ｓｃｈｒｏｄｉｎｇｅｒ方程，并得到其单个包络孤立波子波解，并分析基本流切变对非线性赤道Ｒｏｓｓｂｙ孤立子的影响。  相似文献   

一个引入近地层的区域气候模式   总被引：4，自引：0，他引：4       下载免费PDF全文

汤剑平  苏炳凯  江静  赵鸣  潘益农  符淙斌 《大气科学》2001,25(2):221-230

把近地层引入到NCAR的区域气候模式RegCM2中(简称为RCMC1)，用该模式及1991年梅雨期间的观测资料作了3组模拟试验，并同实况进行了比较。结果表明，在区域气候模式中引入近地层后，能够更合理的模拟出地表及植被同大气之间的感热和潜热通量输送，从而改善模式模拟的月降水及月平均地面温度的分布。l0层的RCMC1比18层RCM具有更优的模拟气候的能力，且一个模式天的计算量节省227s。  相似文献   

稀性泥石流对排导槽的冲磨破坏机理   总被引：5，自引：1，他引：5  

周富春  黄本生  杨钢  陈洪凯 《山地学报》2001,19(5):470-473

针对稀性泥石流特点，从垂直于排导槽边壁方向和平行于排导槽边壁方向对排导槽的受力情况进行比较深入的分析，导出了多个公式，为设计排导槽提供了理论依据。  相似文献   

Spatial variability of soil moisture content and its relation to environmental indices in a semi-arid gully catchment of the Loess Plateau, China   总被引：16，自引：0，他引：16  

Yang Qiu  Bojie Fu  Jun Wang  Liding Chen 《Journal of Arid Environments》2001,49(4):723

The degree of spatial variability of soil moisture and the ability of environmental attributes to predict that variability were studied at the Da Nangou catchment (3·5 km²) in the semi-arid loess area of China. Soil moisture measurements were performed biweekly at five depths in the soil profile (0–5 cm, 10–15 cm, 20–25 cm, 40–45 cm and 70–75 cm) from May to October 1998 and from May to September 1999 using Delta-T theta probe. Results indicated that with increasing soil depth, the mean soil moisture content increases significantly for five layers and the coefficients of variation (CV) also increases with depth from 10–15 cm. It was observed that heavier rains and higher mean moisture contents are often associated with lower spatial variability (CV). Environmental attributes such as land use and topography play controlling roles in the spatial distribution of soil moisture content. However, the relative roles of these environmental indices vary with soil depth. The dominant controls on spatial variability of the time-averaged soil moisture changes from land use, aspect, relative elevation and hillslope position in the surface soil (0–5 cm) to relative elevation, hillslope position and aspect in the subsurface soil (10–15 cm, 20–25 cm), and to land use, relative elevation and slope gradient at larger depths (40–45 cm, 70–75 cm). The dynamic behavior of influences of different environmental indices on the layer-averaged soil moisture depends on several factors. In general, the correlation of soil moisture with slope gradient shows a more significant increase following a greater amount of antecedent precipitation (except for the extremely heavy storms), and declines afterwards. The relation of soil moisture with relative elevation and hillslope position exhibits an opposite trend. It was observed that the influence of land use corresponds to the difference in vegetative characteristics, with a stronger influence in June and August with a greater difference in vegetation. A significant influence of cos(aspect) was found during early spring and autumn with a rapid transient in solar irradiation. Finally, it was found that the sample size is adequate to estimate the catchment mean soil moisture at all five depths and on all 10 observations in 1999 (81 sites), while it is only enough for the upper soil layers (0–5 cm and 10–15 cm) in 1998 (26 sites).  相似文献   

福建省上地幔结构与岩石矿物的基本特征     

王振民  傅玉琴 《福建地质》2001,20(1):7-29

综合研究了福建省上地幔的矿物、岩石、地球化学、地球物理（重、震、电）等有关资料，全面论证上地幔B′与B″层的三维空间特征、可疑地幔岩性、古代与现代地幔岩岩石类型与矿物成分。继而从地幔岩矿物组合，化学成分、微观特征、包裹体、稳定同位素等特点，来探讨第三纪上地幔的成岩环境与动力学，并指出东南沿海岩石圈上地幔减薄斜坡带及其叠生的深切断裂是燕山期双系列岩浆岩形成的深部地质背景。  相似文献   

Regularity of paleowind directions of the Early Cretaceous Desert in Ordos Basin and climatic significance     

Jiang Xinsheng  PAN Zhongxi  Fu Qingping 《中国科学D辑(英文版)》2001,44(1):24-33

By the measurement of the wind directional indicator of the Cretaceous desert in Ordos Basin, the regularity of the paleoprevailing wind directions and pattern of the paleowind belts are revealed. It is considered that the desert was controlled by a planetary wind system. In the early stage, the subtropical high pressure zone drifted south and northwards with short cycles, resulting in the alternation of westerlies and northeast trades; in the late stage, the subtropical high pressure zone drifted southwards with a long cycle, placing the desert under the westerly belt and making the desert completely controlled by the westerly belt. The reconstruction of the paleowind belts has provided the evidence of the general circulation of the atmosphere for the pattern of the circulation before the uplift of the Tibetan Plateau  相似文献   

邢台地震的震后异常分析     

傅德川  张子广 《华北地震科学》1995,13(3):44-50

对１９６６年３月８日邢台６．８级地震后的异常进行了逐项分析与讨论，发现有些震后异常与后续７．２级主震有比较可信的内在联系。本文在归纳邢台震后异常特征的基础上，提出了６条可能在同类条件下对预报后续地震具有普遍意义的意见。  相似文献   

地震灾害快速评估的计算机方法和程序   总被引：4，自引：0，他引：4  

姜立新  李闽峰 《地震》1995,(3):228-233

文中介绍一种在微机上实现的地震灾害快速评估应用软件：ＤＩＳＥＶ，ＤＩＳＥＶ由地震输入系统，图形显示系统，灾害评估系统和数据输出系统等４部分组成，采用确定性的地震灾害评估方法，用Ｃ语言设计完成，ＤＩＳＥＶ操作简单，快速，对震后快速反应工作以及救灾工作有重要意义。  相似文献   

Boundary element method with exterior collocation in two-dimensional elastodynamic problems     

T. M. Fu  J. G. Xiong  Y. K. Cheung 《地震工程与结构动力学》1995,24(1):99-108

In the present paper, the boundary element method with exterior collocation was applied to two-dimensional elastodynamic problems. The stability of the numerical solution was discussed and the collocation rule of source points outside the region being studied was investigated in the frequency domain by means of the computed error in the boundary displacement and the condition number of the coefficient matrix for two typical wave propagation problems. The achieved results are helpful to the practical application of this method to earthquake ground motion analysis.  相似文献   

副热带环流系统在福建春季中期预报中的应用          下载免费PDF全文

张瑞桂  傅秀治 《气象》1995,21(2):23-26

应用谐谱分析同天气图相结合的方法，将１９８９－１９９２年春季２－４月（其中缺１９８９年４月资料）副热带地区超长波分东进型，西退型和稳定加深（强）型；长波分为准静止长波、不连续西退长波和东进长波三种类型，不同的超长波，长波流型给福建春季带不同的中期天气过程。  相似文献