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Owing to the Benjamin-Feir instability,the Stokes wave train experiences a modulation-demodulation process,and presents a recurrence characteristics.Stiassnie and Shemer researched the unstable evolution process and provided a theoretical formulation for the recurrence period in 1985 on the basis of the nonlinear cubic Schr dinger equation(NLS).However,NLS has limitations on the narrow band and the weak nonlinearity.The recurrence period is re-investigated in this paper by using a highly efficient High Order Spectral(HOS) method,which can be applied for the direct phaseresolved simulation of the nonlinear wave train evolution.It is found that the Stiassnie and Shemer’s formula should be modified in the cases with most unstable initial conditions,which is important for such topics as the generation mechanisms of freak waves.A new recurrence period formula is presented and some new evolution characteristics of the Stokes wave train are also discussed in details. 相似文献
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Zhang Ji’en Xiao Wenjiao Windley Brian F. Cai Fulong Sein Kyaing Naing Soe 《International Journal of Earth Sciences》2017,106(4):1391-1408
International Journal of Earth Sciences - The Indo-Burma Range (IBR) of Myanmar, the eastern extension of the Yarlung-Tsangpo Neotethyan belt of Tibet in China, contains mélanges with... 相似文献
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Akira Imai Jumpei Shinomiya Maung Thiha Soe Lucas Donny Setijadji Koichiro Watanabe I Wayan Warmada 《Resource Geology》2007,57(2):230-240
The Selogiri area, situated in Wonogiri regency, Central Java, is one of several gold prospecting areas in the Southern areas Mountain Range in Java, Indonesia. Three types of dioritic–andesitic intrusive rocks occur in the Selogiri area, namely, hornblende andesite porphyry, hornblende diorite porphyry and hornblende diorite, exposed in a half‐circular depression where volcanic breccia and tuff are widely distributed. The occurrence of stockwork quartz veinlets and associated with magnetite and malachite coating along the cracks in the diorite porphyry suggests porphyry type mineralization. This is also supported by the occurrence of polyphase hypersaline fluid inclusions in the stockwork veinlet quartz. Small‐scale miners are mining NS‐trending quartz veins for gold associated with base metal sulfides. These veins are probably epithermal‐type mineralization that overprinted porphyry‐type mineralization. The Neogene intermediate to silicic hydrous magmatism in Java could have formed the porphyry‐type mineralization in Selogiri, as in the rest of the Sunda–Banda arc. 相似文献
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Ruijie Ye Feng Zhou Xiao Ma Dingyong Zeng Feilong Lin Hongliang Li Chenggang Liu Soe Moe Lwin Hlaing Swe Win Soe Pyae Aung 《海洋学报(英文版)》2023,42(2):83-93
Preparis Channel is the very important exchange path of energy and materials between the northern Bay of Bengal and Andaman Sea(AS). A set of hydrographic measurements, a microstructure profiler, and a deep mooring were used to determine the characteristics of water masses, turbulent mixing, and flows in the Preparis Channel. The unprecedented short-term mooring data reveal that a deep current in the deep narrow passage(below 400 m) of the Preparis Channel flows toward the Bay of Bengal(BoB) wit... 相似文献
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An Evaluation of Four Different Wavelet Decomposition Procedures for Spatial Feature Discrimination in Urban Areas 总被引：2，自引：0，他引：2
Texture or spatial arrangement of neighborhood objects and features plays an important role in the human visual system for pattern recognition and image classification. The traditional spectral–based image processing techniques have proven inadequate for urban land use and land cover mapping from images acquired by the current generation of fine–resolution satellites. This is because of the high frequency spatial arrangements or complex nature of urban features. There is a need for an effective algorithm to digitally classify urban land use and land cover categories using high–resolution image data. Recent studies using wavelet transforms for texture analysis have generally reported better accuracy. Based on a high–resolution ATLAS image, this study illustrates four different wavelet decomposition procedures – the standard, horizontal, vertical, and diagonal decompositions – for urban land use and land cover feature extraction with the use of 33×33 pixel samples. The standard decomposition approach was found to be the most efficient approach in urban texture analysis and classification. For comparison purposes and to better evaluate the accuracy of wavelet approaches in image classification, spatial autocorrelation techniques (Moran's I and Geary's C ) and the spatial co–occurrence matrix method were also examined. The results suggest that the wavelet transform approach is superior to all other approaches. 相似文献
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In this study, an empirical model for predicting urban evapotranspiration (ET) is examined for the Phoenix metropolitan area that is in a subtropical desert climate using in situ ET measurements from a local flux tower and remotely sensed moderate-resolution imaging spectroradiometer land products. Annual ET maps of Phoenix are then created for the period from 2001 to 2015 using the empirical model developed. A time-series trend analysis is finally performed using predicted ET maps to discover the spatio-temporal patterns of ET changes during the study period. Results suggest that blue-sky albedo and land surface temperature are two statistically significant variables explanatory to model urban ET for Phoenix. Areas that have experienced significant increases of ET are highly spatially clustered, and are mainly found on the outskirts of the city, while areas of decreasing ET are generally associated with highly developed areas, such as downtown Phoenix. 相似文献
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Albedo is a key forcing parameter controlling the planetary radiative energy budget and its partitioning between the surface and the atmosphere. Characterizing and developing high resolution albedo for an urban environment in arid regions is important because of the high urbanization rate in these regions and because of the high land-cover heterogeneity within urban settings. Using a Monte Carlo simulation of a multi-variable regression, we (a) correlate directional solar reflectance (albedo) ground measurements from Phoenix, AZ, with four narrowband reflectance data from QuickBird, and (b) developed a new set of coefficients for converting QuickBird narrowband reflectances to albedo. The albedo models were then applied to a second image over Las Vegas, NV, to assess their feasibility and accuracy. Two wavebands, visible-near infrared (VNIR) and total shortwave albedo, were evaluated for two reflectance models: surface and top-of-atmosphere. Results show that it is possible to accurately estimate directional albedo from high resolution imagery, specifically QuickBird, with the most accurate result from an atmospherically corrected VNIR model. The methodology presented in this paper could thus be applied in other urban areas to obtain a first order estimation of albedo. The new set of coefficients can be applied as first order albedo estimate by researchers, urban planners, developers and city managers interested in the influence of high-resolution albedo on a myriad of urban ecosystem processes. 相似文献
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An exploration of spatial dispersion, pattern, and association of socio-economic functional units in an urban system 总被引：2，自引：0，他引：2
Hypotheses based on a set of socio-economic, cultural, and political functional units are examined. The geographic techniques employed in the study include spatial mean, standard distance, standard deviational ellipse, nearest neighbor analysis, and spatial analysis on a network: cross K function and network cross K function. The study not only explores the spatial pattern, distribution, and association of key socio-economic, cultural, and political units which could reveal internal structures and activities of an urban system, but also demonstrates a number of operational procedures that permit applications of traditional and advanced spatial analysis approaches in the study of real urban systems. 相似文献
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The supply of iron ore closest to the target grade with lowest operation cost is the main concern for the ore producer in mining industries. An automatic optimal reclaiming system to reclaim iron ore from stockpiles using the bucket wheel reclaimer (BWR) is proposed. However, this paper only presents a study on identifying optimal stockpile voxels for the target quantity and quality grade. Stockpiles here are represented by combinations of voxels, each possessing certain quality composition. The main focus of this paper is to identify the combination of voxels from available stockpile voxels that will fulfil quality and quantity demand of iron ore while maintaining BWR minimum movement on reclaiming. 相似文献