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991.
奇异的波至现象 总被引:1,自引:0,他引:1
1997年,笔者在水力压裂后砂岩产油井中进行高分辨率VSP工作时,除观测到常规纵波及转换波,还观测到来自产油层的几种奇异的慢速波至。由于该慢速波至的性质不明,按视速度从高到低分别命名为W1,W2,W3,…(W为wave的第1个字母),在顺5井裂隙优势方向,1210m深度上观测到5种反射波;反射纵波,反射转换波,W1,W2,W3波,在裂隙非优势方向上,W2,W3波没有出现,在顺4井1532m深度上观测到4种反射波;反射纵波,反射转换波,还有2种慢速波至,为了区别于顺5井中观测到的慢速波至,将其命名为W4,W5波。结合该区钻井,测井,地面地震,井间地震等资料对观测到的慢速波至进行了详细分析,分析结果表明:该慢速波至既不属于不均匀介质产生的绕射波,侧界面产生的反射波,槽波,管波,斯通利波,也与Biot慢纵波动力学特征相悖,现有波动理论不能解释这种慢速波至现象,这意味着地球内部介质中存在人类还未认识的弹性波传播规律。 相似文献
992.
提高地震勘探分辨率是一个系统工程,必须在野外采集,资料处理等方面采取各种不同手段,达到提高分辨率的目的。采用低爆速细长型药柱震源,在提高地震勘探分辨率方面具有特殊的效果,在研究中发现,同时接收纵波和转换横波,与高爆速炸药相比,低爆速细长型震源药柱可以有效地拓宽频带(纵波频带达220Hz以上),提高目的层反射波的主频(纵波主频达120Hz以上),低爆速细长型震源药柱在地震勘探中的推广应用。必将有效地提地震勘探的分辨率。 相似文献
993.
994.
EXPERIMENT ON THE FORECAST OF CHARACTERISTIC QUANTITIES OF ATMOSPHERIC TURBULENCE BY MESOSCALE MODEL MM5 下载免费PDF全文
In nested nonhydrostatic mesoscale model MM5,the characteristic quantities of atmosphericturbulence,i.e.,the standard deviations of the turbulent fluctuated speeds for three directions inPBL are computed by Mellor-Yamada's level 2.5 closure scheme.The magnitudes and the verticalprofiles of these quantities computed from the model are closely connected with temperature andwind speed profiles as well as the type of the ground with a significant diurnal variation,and are inagreement with known magnitudes and regularities in different stratification conditions.Hence themethod in this paper is reasonable and convincible.Their horizontal distribution depends on thehorizontal distribution of the stratification.The method of predicted characteristic quantities ofturbulence from mesoscale model in this paper can be used in the problem of atmospheric diffusionand atmospheric environment. 相似文献
995.
高速滑坡发生的危险斜坡判别 总被引:11,自引:3,他引:11
高速滑坡发生之前的危险斜坡判别是高速滑坡发生时间预报和减灾防灾的基础工作。危险斜坡判别的主要内容是危险斜坡的空间位置和危险程度。本文从高速滑坡形成发生的因子分析入手; 应用数理统计、模糊数学与专家经验相结合的综合分析方法; 采用黄金分割的原理; 建立了高速滑坡发生的危险斜坡判别的指标体系和危险度判别模型。 相似文献
996.
多面函数拟合法及其在建立中国地壳平面运动速度场模型中的应用研究 总被引:20,自引:4,他引:20
基于现有的GPS观测值,将多面函数拟合法用于速度场模型的建立,得到了目前中国覆盖范围最广、分布最均匀、有实用价值的中国地壳平面运动整体速度场图像和NNR-NUVEL1A全球板块运动模型下的平面运动速度场图像。 相似文献
997.
对苍山5.2级地震前后出现的跨断层形态异常特征进行了分析,并系统地分析了由跨断层形变测量资料提取无量纲年速率比γh的时空分布和动态演化特征。 相似文献
998.
The Statistical Prediction Of Offshore Winds From Land-Based Data For Wind-Energy Applications 总被引:3,自引:0,他引:3
John L. Walmsley Rebecca J. Barthelmie William R. Burrows 《Boundary-Layer Meteorology》2001,101(3):409-433
Land-based meteorological measurements at two locations on the Danish coast are used to predict offshore wind speeds. Offshore wind-speed data are used only for developing the statistical prediction algorithms and forverification. As a first step, the two datasets were separated into ninepercentile-based bins, with a minimum of 30 data records in each bin. Next, the records were randomly selected with approximately 70% of the data in each bin being used as a training set for development of the prediction algorithms, and the remaining 30% being reserved as a test set for evaluation purposes. The binning procedure ensured that both training and test sets fairly represented the overall data distribution.To base the conclusions on firmer ground, five permutations of these training and test sets were created. Thus, all calculations were based on five cases, each one representing a different random selection from the same data, but maintaining the (approximate) 70-30 split in each bin. This procedure served to ensure that conclusions were not based on a single randomly-selected case. Two statistical methods are employed:multiple linear regression (MLR), and Classification and Regression Trees(CART). MLR produces excellent results using only land-based predictors.The CART results are similar to those from MLR, and tend to be slightly better.Retired 相似文献
999.
一种全局优化算法:遗传算法-单纯形法 总被引:20,自引:0,他引:20
针对遗传算法搜索效不高和早熟的缺点,本文提出了将遗传算法和单纯形法组合的一种全局优化算法,并用七个典型检验函数验证了此方法的有效性。 相似文献
1000.
Auto-correlation analysis of ocean surface wind vectors 总被引:1,自引:0,他引:1
Abhijit Sarkar Sujit Basu A. K. Varma Jignesh Kshatriya 《Journal of Earth System Science》2002,111(3):297-303
The nature of the inherent temporal variability of surface winds is analyzed by comparison of winds obtained through different
measurement methods. In this work, an auto-correlation analysis of a time series data of surface winds measuredin situ by a deep water buoy in the Indian Ocean has been carried out. Hourly time series data available for 240 hours in the month
of May, 1999 were subjected to an auto-correlation analysis. The analysis indicates an exponential fall of the autocorrelation
in the first few hours with a decorrelation time scale of about 6 hours. For a meaningful comparison between satellite derived
products andin situ data, satellite data acquired at different time intervals should be used with appropriate ‘weights’, rather than treating
the data as concurrent in time. This paper presents a scheme for temporal weighting using the auto-correlation analysis. These
temporal ‘weights’ can potentially improve the root mean square (rms) deviation between satellite andin situ measurements. A case study using the TRMM Microwave Imager (TMI) and Indian Ocean buoy wind speed data resulted in an improvement
of about 10%. 相似文献