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171.
Based on the temperature of the black body (TBB), station observed and NCEP reanalysis data, the impacts of the eastward propagation of convective cloud systems over the Tibetan Plateau on the southwest vortex (SWV) formation that occurred at 1800 UTC on 29 June 2003 are analyzed by using the Zwack-Okossi (Z-O) equation to diagnose the thermal and dynamic processes. It is found that, in summer, severe convective activities often occur over the Tibetan Plateau due to the abundant supply of moisture. The convective cloud near the east edge of the plateau could move eastward with a short-wave trough in the westerly. The divergent center that is induced by latent heat release, which is associated with severe convective activities, moves out with the convective cloud and contributes to the low level decompression which is favorable for the formation of plateau edge cyclogenesis (PEC). The Z-O equation indicates that, in this case, the latent heat release and convergence are the two most important factors for SWV formation, which amounts to about 42% and 15% of the term TOTAL, respectively. It is implied that the thermal process effect was more important than the dynamic process during SWV formation. 相似文献
172.
By using daily total precipitable water(TPW) amount from the ECMWF reanalysis(ERA-44a) data in 1958-2001,the north edge of the Asian sub-tropical summer monsoon is defined by a normalized precipitable water index(NPWI),and its climatology and interannual/interdecadal variability are examined.The results show that two monsoon systems(the Indian and East Asian monsoon systems) can be identified in terms of monsoon edge defined by the NPWI over Asia.The mean north edge goes in the west-east direction along ... 相似文献
173.
HU Qingwu XUAN Jiabin 《地球空间信息科学学报》2001,4(1):50-55
1 IntroductionWiththerapiddevelopmentofaerialandspaceremotesensingtechnique,thedigitalcamerahasbeenexplored ,andmappingexperimentswiththiskindofdigitalimagesarebeingprocessedastheregularmodeofareophotogrammetry .Ontheotherhand ,thetechniqueofintegrationo… 相似文献
174.
F. I. González K. Satake E. F. Boss H. O. Mofjeld 《Pure and Applied Geophysics》1995,144(3-4):409-426
The 25 April 1992 Cape Mendocino earthquake generated a tsunami characterized by both coastal trapped edge wave and non-trapped tsunami modes that propagated north and south along the U.S. West Coast. Both observed and synthetic time series at Crescent City and North Spit are consistent with the zero-order edge wave mode solution for a semi-infinite sloping beach depth profile. Wave amplitudes at Crescent City were about twice that observed at North Spit, in spite of the fact that the source region was three times farther from Crescent City than North Spit. The largest observed amplitude was due to an edge wave which arrived almost three hours after the initial onset of the tsunami; since such waves are highly localized nearshore, this suggests that the enhanced responsiveness at Crescent City is at least partly due to local dynamic processes. Furthermore, the substantially delayed arrival of this wave, which was generated at the southern end of the Cascadia Subduction Zone, has significant implications for hazard mitigation efforts along the entire U.S. West Coast. Specifically, this study demonstrates that slow-moving but very energetic edge wave modes could be generated by future large tsunamigenic earthquakes in the CSZ, and that these might arrive unexpectedly at coastal communities several hours after the initial tsunami waves have subsided. 相似文献
175.
简要地讨论几种典型的空间域图像平滑方法,提出了一种新的保护图像边沿细节的平滑方法──补偿型中值法,并设计了一个基于知识的自适应平滑处理系统的框架。 相似文献
176.
通过庐枞中生代火山岩地区成矿时空结构的研究,提出了玢岩型铁硫多金属矿床定位的动力学——边缘定位机制,总结出该区的4种边缘定位形式和引起边缘定位的两方面动力学因素,最后建立了该区构造、火山—岩浆、岩性多因素控制的边缘定位模式. 相似文献
177.
G. M. Laslett 《Mathematical Geology》1982,14(2):125-140
This paper reviews techniques for correcting for bias incurred when incomplete observations form part of a data set. The similarities and differences between biases due to censoring and edge effects are emphasized, the latter being of importance when the distribution of joint traces is estimated from an exposure. A new technique for analyzing line transect data is presented, and a new analysis of published data on joint trace lengths given. 相似文献
178.
青藏高原北缘银石山地区地貌年代学初步研究 总被引:6,自引:0,他引:6
青藏高原北缘银石山地区可划分出7类一级地貌类型:强抬升断块区、弱抬升断块区、低丘区、早期夷平面残留区、晚期准夷平面分布区、冲洪积平原、残积缓丘区等。通过相关沉积物的光释光和石英电子自旋共振年龄以及覆于早期夷平面、后期山丘、夷平低地或堆积台面等之上的火山岩年龄测年,重塑了晚新生代以来的地貌演化过程:中新世中晚期—上新世中期为主夷平面发育时期,上新世晚期(3.7Ma)主夷平面解体,强(弱)抬升断块区和低丘山地等开始形成。早更新世早期在低丘区中形成夷平低地或堆积台面,中后期抬升断块区与低丘区相间的地表形貌特征进一步强化。中更新世早期(0.64Ma)残积缓丘区形成,中期(0.43Ma)嵩华山北面形成一级冰斗,中后期(0.365Ma)低丘区主要斜坡地貌成型,末期(0.178Ma)强抬升断块区的主要沟谷地貌基本成型。晚更新世以来主要河流阶地形成,其间在0.037Ma前后冲洪积平原形成。 相似文献
179.
讨论了多源影像融合技术在改善目标识别与提取效果中的一些应用,给出了部分试验结果,说明了多源数据融台技术是未来目标自动识别系统的重要组成部份。 相似文献
180.
Gravity evolution and earthquake activities of the northeastern edge of Qinghai-Xizang block 总被引:1,自引:0,他引:1
Introduction Earthquake is closely tied up with gravity on the basis of crustal deformation and crustaldensity change. With the accumulation of stress around the epicenter, the spatial position ofground point and density crustal medium will change with strain during the seismogenic processof an earthquake. All these factors will bring about the change of gravity field. Since the Xingtaiearthquake in China in 1966, mobile gravity measurements in a large scale and the studies ongravity var… 相似文献