Experiments of Reconstructing Discrete Atmospheric Dynamic Models from Data (I)     

Lin Zhenshan  Zhu Yanyu  Deng Ziwang 《大气科学进展》1995,12(1):121-125

In this paper, we give some experimental results of our study in reconstructing discrete atmospheric dynamic models from data. After a great deal of numerical experiments, we found that the logistic map, xn +1= 1-uxn2 could be used in monthly mean temperature prediction when it was approaching the chaotic region, and its predictive results were in reverse states to the practical data. This means that the nonlinear developing behavior of the monthly mean temperature system is bifurcating back into the critical chaotic states from the chaotic ones.  相似文献   

渭南地区建设地理研究   总被引：2，自引：1，他引：2  

陈传康  石俊杰 《地理学报》1992,47(4):353-360

本文应用建设地理学的理论,对陕西渭南地区的区域开发提出了以下战略构想和措施。①建立重轻农和第三产业协调发展的产业结构模式;②建立新兴的重化工、有色金属、能源和建材工业基地;③建立开放型的现代农业体系;④建立整体协调的区域社会经济结构;⑤疏通各种渠道,吸引外资;⑥开发旅游资源,完善旅游服务体系;⑦加强生态环境建设;⑧进一步解放思想,提高干部和公民的现代文化和改革开放意识。  相似文献   

求解线性方程组的一种迭代方法——ART算法的一种改进     

张志海  杨建辉 《CT理论与应用研究》1994,3(4):20-23

本文用Ｓｃｈｍｉｄｔ正交化方法对阻尼ＡＲＴ算法进行了改进，并以此为基础，通过与一种投影迭代法的结合给出一种求解线性方程组的迭代方法，同时指出即使线方程组不相容时，由此法所构造的向量序列将收敛于其Ｍｏｏｒｅ－Ｐｅｎｒｏｓｅ广义逆解。  相似文献   

全球超级古陆重建研究的新进展   总被引：1，自引：0，他引：1  

谭富文  潘桂棠 《四川地质学报》2000,20(1):6-11

介绍了新元古代－早古生代超级大陆的重建研究,表明中元古代以来,地球上先后经历了罗迪尼亚－冈瓦纳－潘基亚等几次超级大陆的拼合与裂解过程,罗迪尼亚古陆的拼合源于中元古代晚期（１３００～１０００Ｍａ）发生的全球性格林威尔造山事件。东冈瓦纳（澳大利亚、东南极和部分非河）作为一个整体最早与劳伦古陆分离,导致了太平洋的张开。进一步的裂解产生了组成西冈与纳的各克拉通块体。在泛非造山和期间（７２０～５００Ｍａ）西  相似文献   

On accurate dense stereo-matching using a local adaptive multi-cost approach     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Defining pixel correspondences among images is a fundamental process in fully automating image-based 3D reconstruction. In this contribution, we show that an adaptive local stereo-method of high computational efficiency may provide accurate 3D reconstructions under various scenarios, or even outperform global optimizations. We demonstrate that census matching cost on image gradients is more robust, and we exponentially combine it with the absolute difference in colour and in principal image derivatives. An aggregated cost volume is computed by linearly expanded cross skeleton support regions. A novel consideration is the smoothing of the cost volume via a modified 3D Gaussian kernel, which is geometrically constrained; this offers 3D support to cost computation in order to relax the inherent assumption of “fronto-parallelism” in local methods. The above steps are integrated into a hierarchical scheme, which exploits adaptive windows. Hence, failures around surface discontinuities, typical in hierarchical matching, are addressed. Extensive results are presented for datasets from popular benchmarks as well as for aerial and high-resolution close-range images.  相似文献   

小流量、低水头观测泉脱?集气装置改造实验研究——以延庆松山泉气氡为例     

高玲  周永刚  吕毅夫  乔永军 《中国地震》2021,37(3):728-736

小流量、低水头观测泉使用常规脱?集气装置,达不到观测气量的要求,会直接影响化学气体观测质量。本文以松山观测泉为研究对象,结合台站观测条件,通过技术改造和实验研究,制作了恒流溅落式脱?集气装置,对气氡观测结果进行了连续观测分析,获得了完整的年动态变化曲线。观测结果表明,该脱?集装置能够较好地解决小流量、低水头观测泉存在的流量、气量、水量不稳定的问题,使气氡观测的稳定性得到明显提高,为全国其他小流量、低水头观测泉脱?集气装置的技术改进提供了范例。  相似文献   

基于重构激发信号的电磁式可控震源相关检测参考信号方法研究          下载免费PDF全文

杨志超  姜弢  徐学纯  林君  贾海青  马瑞琪  陈振振 《地球物理学报》2016,59(1):318-329

针对电磁式可控震源地震数据的相关检测,研究发现,在地下结构复杂、基板-大地耦合不佳时,常规方法——基于震源控制信号或基板附近信号作为参考信号检测得到的地震记录中,存在子波到时误差和虚假多次波问题.本文分析了上述问题的理论原因,并提出基于重构激发信号的相关检测参考信号方法(Correlation Detection Reference Signal Based on the Reconstructed Excitation Signal,CDRSBRES).首先,利用直达波与其他地震波到时不一致的特点,从震源基板附近信号中分离、提取直达波.然后,利用直达波重构震源激发信号并作为参考信号对地震数据进行相关检测.最后,应用谱白化技术提高检测结果质量.数值模拟研究表明,重构激发信号与理想激发信号的相关系数为0.9869,达到高度线性相关,CDRSBRES方法检测的地震记录在子波到时和波形特征上均与模型相符.随后,在某金属矿区开展了可控震源对比实验.与液压式可控震源MiniVib T15000检测结果相比,电磁式可控震源PHVS 500的检测结果中:基于震源控制信号的检测结果存在子波到时误差约0.012s,对应垂向精度误差约11.16m;基于基板附近信号的检测结果部分区域出现虚假多次波,信噪比降低;而CDRSBRES方法的检测结果子波到时误差约0.001s,对应垂向精度误差约0.93m,波形特征一致,相同区域无虚假多次波.综上,本方法适用于电磁式可控震源地震数据的高精度检测,尤其对于地下结构复杂区域的高分辨率地震勘探具有重要意义.  相似文献   

在藻型富营养湖泊中恢复大型水生植物净化水质的物理生态工程——以中国太湖五里湖为例     

张圣照  濮培民  王国祥 《湖泊科学》1998,10(S1):529-538

In the barren lake, algae-type eutrophication lake, fifteen aquatic vascular plants were introduced and vegetated in our enclosures of physical-ecological engineering. The area of each enclosure is 200 m², with length of 40m, width of 5m and depth of 1.8m. From 1995 to 1997, we had successfully vegetated 15 communities with the propagation techniques of pot-culture and sturdy seedling. The communities included floating, leave-floating and submerged macrophytes, such as Altemanthera phyiloxeroides, Eichhomia crassipes, Trapa maximowiczii, Nymphoides peltata, Potamogeton maackianus, P. crispus, Myriophyllum spicatum, Hydrilla verticillata, Elodea nuttallii, etc. These aquatic macrophytes not only adapted themselves to the environment but also purified the lake water.  相似文献   

A simple experimental method to regain the mechanical behavior of naturally structured marine clays     

《Applied Ocean Research》2019

Quantitative laboratory studies on the structural behavior of natural intact marine clays require a large number of identical natural samples leading to an expensive and challenging task. This study proposes a simple method to reconstruct an artificial structured marine clay as the state of its natural intact clay at both macro and micro levels. For this purpose, the Shanghai marine clay is selected and mixed with low cement contents (1–6%). The clay-cement slurry is mixed in a container with the ice-covered sides at a low temperature about 0 ± 2 °C to postpone the hydration reactions until consolidation began. The purpose of adding cement is to generate the inter-particle bonding and structure in reconstituted samples. Initially, the reconstituted samples are consolidated under the in situ stress of 98 kPa and then under the pre-consolidation pressure of 50 kPa. Mechanical characteristics such as compression index, yield stress, unconfined compression strength, shear strength ratio, and the stress paths from triaxial tests are compared with natural intact clay accordingly. Scanning electron microscope and mercury intrusion porosimetry analyses are also performed to analyze the microstructure of clays for comparison. Furthermore, the proposed method is also examined by using natural intact marine clays of different locations and characteristics.  相似文献   

基于DIEOF方法重构海表叶绿素a遥感缺失数据     

马翱慧  刘湘南  刘美玲  龙亚谦 《海洋通报》2014,33(5):576-583

以2007年1月到2010年12月的MODIS Aqua CHL-a Level 2海表水色产品为基础数据,获得南海北部海域海表叶绿素a浓度的月平均影像集,基于影像集数据的时空相关性利用DIEOF(Data Interpolating Empirical Orthogonal Functions)方法重构其缺失数据。通过分析重构前后数据变化、验证重构结果的时空特征、计算模型精度指标等对重构结果进行评价。研究结果表明:DIEOF方法重构的MODIS海表叶绿素a影像,能够体现研究区海表叶绿素a的时空变化特征,重构结果的复相关系数R2可达到0.98,平均绝对误差MAE小于0.01;该方法重构过程中无需先验信息,易操作,能够有效重构大面积成片缺失或缺失比例较高的影像。  相似文献