论塔吉克斯坦杜尚别——瓦赫什地区地震活动性的地质标志问题     

A.P.伊索 《内陆地震》1996,10(3):276-280

据航、卫片解译、杜尚别－瓦赫什地区有１１条线性结构。由它们构成的努涅克和科摩索姆洛巴德构造结为晚更新世一全新世活动构造，未来可能发生强震及灾难性地震。  相似文献   

火箭观测到的中层垂直速度扰动细微结构          下载免费PDF全文

吴永富  H. -U. Widdel 《地球物理学报》1996,39(Z1):36-42

使用一枚携带ｃｈａｆｆ的火箭观测到的垂直速度数据，研究中层大气垂直速度扰动细微结构。结果表明，垂直速度扰动有明显的层状结构，各层厚度约１５０－５００ｍ，层间垂直分离距离在几百米到１－３ｋｍ间。在垂直速度方差和低Ｒｉ数峰值间以及动力不稳定和ＭＳＴ雷达回波区域间有好的对应关系。水平速度垂直波数谱与饱和谱在谱斜率和谱振幅上存在好的一致．这些观测结果表明，火箭测量到的细微结构可以用波场饱和解释。  相似文献   

CHARACTERISTICS OF MESOSCALE FLOOD-MAKING TORRENTIAL RAIN SYSTEM SIMULATED BY HIGH RESOLUTION LIMITED AREA MODEL—NUMERICAL SIMULATION OF A HEAVY RAIN PROCESS DURING MEIYU SEASON IN 1991^*          下载免费PDF全文

Zhu He  E. Rasmussen 《Acta Meteorologica Sinica》1996,10(3):284-294

An experimental work on the transplant of high resolution limited area model(HIRLAM) isfirstly introduced into China.For the implementation,first of all is to adjust a new geographicalcoordination and to remove the instability caused by the Tibetan Plateau,the roof of the world.Then,we have applied this model to simulate a flood-making torrential rain process which occurredin the Changjiang-Huaihe River Valley in July 1991.That revealed the formation,development andmovement of a mesoseale heavy rain system which had made a disastrous flood event in the middleand lower reaches of Changjiang River Valley.The result encourages us to use the HIRLAM for the researches on the Meiyu belt,the salientfeature of precipitation of East Asia,and the numerical prediction of heavy rains in China.  相似文献   

美国加州帕克菲尔德附近的土耳基平地场地效应试验区的弱运动观测和模拟     

C.H.Cramer  杨宝仁 《世界地震译丛》1996,(3)

为了测定弱运动场地响应的稳定性和试验土工技术测量预测场地响应的能力,在穿过加州帕克菲尔德附近的土耳基平地(Turkey Flat)场地效应试验区的一些场地,对经验转换函数和理论场地放大作用函数进行了比较。用傅里叶振幅频谱比方法,对给定场地测定了相对于基岩参考场地的观测场地响应。进行了两种单独的研究:剖面研究和特定场地研究。相隔2km的两个横跨谷地岩石的台站之间的表面基岩场地响应差异不超过30％。在剖面研究中,在距试验区的谷地上间隔100m的一些场地使用的探测器间隔为10和20m。跨过10m的探测器间隔,表面硬土场地响应可重复测得,差异不超过30％。在硬土场地响应中,对于20m的探测器间隔,存在偶尔出现的显著变化,在10～20Hz频带内可差2至3倍。在硬土场地响应中,对于探测器间隔为100m时存在系统的变化,在5～20Hz频带内相对于土层厚度的变化可差3至10倍。在土耳基平地发现了特定场地弱运动平均频谱比和其标准偏差,可用作硬土条件强运动转换函数的经验预测值。使用由计算机程序SHAKE得到的相对放大作用函数模拟了观测的转换函数。使用接近原地测量的阻尼值,比使用实验室实验测定的阻尼值获得了共振峰值振幅更好的拟合。土耳基平地标准土工技术模型的不精确性(Real,1988),导致了计算的弱运动转换函数与观测的弱运动转换函数相比的不精确性。观测转换函数的模拟表明,模型拟合对5％的S波速度变化敏感。土耳基平地现场测量S波速度有10％～20％的误差。这一情况表明,仅仅根据现场土工技术的测量,对弱运动的精确和一致的预测是不可能的。  相似文献   

A SIMPLIFIED APPROACH TO MODELING 3D SEDIMENT-LADEN TURBULENT FLOWS     

Donghuo ZHOU  Sam S.Y.WANG 《国际泥沙研究》1996,(1)

ＡＳＩＭＰＬＩＦＩＥＤＡＰＰＲＯＡＣＨＴＯＭＯＤＥＬＩＮＧ３ＤＳＥＤＩＭＥＮＴ－ＬＡＤＥＮＴＵＲＢＵＬＥＮＴＦＬＯＷＳＤｏｎｇｈｕｏＺＨＯＵａｎｄＳａｍＳ．Ｙ．ＷＡＮＧＡｂｓｔｒａｃｔ：Ａ３－ｄｎｕｍｅｒｉｃａｌｍｏｄｅｌｆｏｒｓｉｍｕｌａｔｉｎｇｓ...  相似文献   

A NEW QUANTITATIVE WAY FOR DETERMINING LEAF AREA INDEXAND NET PRIMARY PRODUCTIVITY IN REGIONAL SCALE   总被引：1，自引：0，他引：1  

Zhang Renhua 《地理学报(英文版)》1996,(4)

IntroductionThemaJorpurposeforremotesensingistoobtuinqUantitativevaluabledrirmationonvanousaPplicahons.PanicularlybiophysicalparametersinwionalandglobalscaleareofintereSttoanumberofdomams.ForinStancem,croPyteldestiInatinleafareaindex,chiorophyllcontentandheightofcroparecruaalindex.EvaPotranSirationinroponalscalenedstogctdistnbtaloninformationofcrophdghttoinferrowiessOfsuffoceandsoon.AsthoopthenormaldifferenceVegetaonindex(NDVI)hasbecameaverypoPularmethodtoeinmateLAI,therelationshipbet…  相似文献   

白垩纪红层冰筏沉积的古气候及古地理意义   总被引：3，自引：1，他引：3       下载免费PDF全文

王东坡  刘立  L. A. Frakes 《沉积与特提斯地质》1996,16(4):6-11

冰筏沉积是负载沉积物的冰块进入海洋或湖泊中，冰块融化沉积物附落所形成的，它们可形成于高海拔具有明显气候垂直分带的低纬度地区或者是高纬度地区。我们在研究松辽盆地白垩纪古气候时，首次在泉头组层中发现冰筏沉积。根据泉头组孢粉组合的研究透明，它们除了具有热带－亚热植物的孢粉以外，还有少量喜冷分子混生现象。  相似文献   

The structure of low frequency phenomena in the tropics and its interaction with the extratropics     

Peter J. Webster  Min Dong 《大气科学进展》1992,9(1):1-16

The structure of planetary scale low frequency phenomena in the tropics is studied, and an attempt is made to de-termine its influence and interactions with phenomena at higher latitudes.In the tropics, it is found that the majority of the variance in the zonal wind structure is made up in wave num-bers 1 and 2. During warm events in the Pacific Ocean, when the Southern Oscillation Index is negative, almost all of the variance resides in the gravest mode which undergoes a 40o eastward phase shift. Meanwhile, the second logitudinal mode almost disappears. On the other hand, the meridional wind field possesses maximum amplitude at higher wave numbers. However, near the equator, the amplitude is small with extreme values occurring in the subtropics. The difference in scale and the location of extrema of the meridional and zonal wind components indicate that the tropical atmosphere is responding to two different driving mechanisms,Correlation analyses between variations of the zonal wind at reference points along the equator with variations of component elsewhere show that there are strong logitudinal connections. The strongest correlations between the tropics and higher latitudes exist in the region of the equatorial westerlies. In fact, stronger correlations occur between variations in U anywhere along the equator and the middle latitudes to the north and south of the equatorial wester-lies than to the latitudes immediately to the north and south of the reference points. We interpret this “remote” corre-lation pattern as indicating a two-stage teleconnection process which emphasizes the importance of the equatorial tropical westerlies of the Pacific Ocean as a “corridor” of communication between the low and high latitudes. The regionality of the correlations confirms, to some extent, recent theoretical development regarding trapped equatorial modes. Finally, time lagged correlations from plus and minus six months between variations of U and OLR indicate that the interactions between the extratropics and low latitudes possess an organized sequence. The extratropical in-fluence appears to propagate into the tropics followed by an eastward propagation along the equator. Finally, a propagation from the tropics to the extratropics in the upper troposphere occurs in the eastern Pacific Ocean. The time-lagged correlation sequence does not appear to be symmetric about the equator.  相似文献   

Some experiments with multivariate objective analysis scheme of heights and winds using optimum interpolation     

S. K. Sinh  S. G. Narkhedkar  D. R. Talwalkar  S. Rajamani 《大气科学进展》1992,9(4):431-440

A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. The height-height correlations calculated using daily data of four July months (1976-1979), are used to derive the other autocorrelations and cross-correlations assuming geostropic relationship. A Gaussian function is used to model the autocorrelation function. Since the scheme is multivariate the regression coefficients (weights) are matrix.Near the equator, the geostrophic approximation relating mass and wind is decoupled in a way similar to Bergman (1979). The objective analyses were made over Indian and adjoining region for 850, 700, 500, 300 and 200 hPa levels for the period from 4 July to 8 July 1979, 12 GMT. The analyses obtained using multivariate optimum in-terpolation scheme depict the synoptic situations satisfactorily. The analyses were also compared with the FGGE ana-lyses (from ECMWF) and also with the station observations by computing the root mean square (RMS) errors and the RMS errors are comparable with those obtained in other similar studies.  相似文献   

气候变化影响的研究     

Ю.А.济拉埃里  李怀川 《陕西气象》1992,(2)

由于大气中温室气体的增加,导致世界气候变暖,可能影响到生态环境和社会经济。这是政府间一批专家关于全球气候变暖的影响所作的重要工作。来自24个国家和地区的150多名学者和专家参加会议并准备了  相似文献