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31.
32.
D. C. Mason I. J. Davenport R. A. Flather C. Gurney G. J. Robinson J. A. Smith 《Estuarine, Coastal and Shelf Science》2001,53(6):759
A sensitivity analysis of the waterline method of constructing a Digital Elevation Model (DEM) of an intertidal zone using remote sensing and hydrodynamic modelling is described. Variation in vertical height accuracy as a function of beach slope is investigated using a set of nine ERS Synthetic Aperture Radar (SAR) images of the Humber/Wash area on the English east coast acquired between 1992 and 1994. Waterlines from these images are heighted using a hydrodynamic tide-surge model and interpolated using block kriging. On 1:500 slope beaches, an average block height estimation standard deviation of 18–22 cm is achieved. This rises to 27 cm on 1:100 slope beaches, and 32 cm on 1:30 slope beaches. The average heighting error at different slopes is decomposed into components due to waterline heighting error, inadequate sensor resolution and interpolation inaccuracy. It is shown that, at 1:500 slope, waterline heighting error and interpolation inaccuracy are the main error sources, whilst at 1:30 slope, errors due to inadequate sensor resolution become dominant. The ability of the technique to generate intertidal DEMs for almost the entire coastal zone in a complete ERS SAR scene covering 100×100 km is demonstrated. 相似文献
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数字地球与海洋科学的发展 总被引:3,自引:0,他引:3
本文从数字地球的概念出发,根据海洋科学的发展要求,详细论述了数字地球与海洋科学的发展关键。并提出了海洋科学的新的发展战略和配套技术的开发研究理论,从而为我国海洋事业的发展和数字地球的建立有一个协调和统一的认识观点。 相似文献
35.
程恩 《海洋通报(英文版)》2001,3(2)
A new method of coding and decoding in the system of underwater image transmission is introduced, including the rapid digital frequency synthesizer in multiple frequency shift keying,image data generator, image grayscale decoder with intelligent fuzzy algorithm, image restoration and display on microcomputer. 相似文献
36.
The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied.We use Goertzel algorithm for source decoding and MFSK for modulation.Turbo code is used for channel coding and decoding.The purpose is to implement underwater video image data transmission. 相似文献
37.
Experimental Investigation of Instantaneous Properties of Wave Slamming on the Plate 总被引:1,自引:0,他引:1
The purpose of this paper is to investigate the instantaneous properties of wave slamming on the plate structure of an open structure.The advanced instantaneous measuring technique-Particle Image Velocimetry(PIV) is applied to acquire the instantaneous velocity field of wave slamming.From the cross-correlation analysis results of the images captured by the CCD camera,the flow fields of wave impacting on the structure are displayed visually,and the instantaneous whole-field fluid velocity vectors are obtained.The relation between the instantaneous peak impacting pressures and the instantaneous velocities of water particles is studied by probability analysis. 相似文献
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Darío R. Minkoff Mauricio Escapa Flix E. Ferramola Silvio D. Maraschín Jorge O. Pierini Gerardo M.E. Perillo Claudio Delrieux 《Estuarine, Coastal and Shelf Science》2006,69(3-4):403
The Bahía Blanca Estuary (38° 50′ S, and 62° 30′ W) presents salt marshes where interactions between the local flora (Sarcocornia perennis) and fauna (Chasmagnathus granulatus) generate some kind of salt pans that alter the normal water circulation and condition its flow and course towards tidal creeks. The crab–vegetation dynamics in the salt marsh presents variations that cannot be quantified in a reasonable period of time. The interaction between S. perennis plant and C. granulatus crab is based on simple laws, but its result is a complex biological mechanism that causes an erosive process on the salt marsh and favors the formation of tidal creeks. To study it, a Cellular Automata model is proposed, based on the laws deduced from the observation of these phenomena in the field, and then verified with measurable data within macroscale time units. Therefore, the objective of this article is to model how the interaction between C. granulatus and S. perennis modifies the landscape of the salt marsh and influences the path of tidal creeks. The model copies the basic laws that rule the problem based on purely biological factors.The Cellular Automata model proved capable of reproducing the effects of the interaction between plants and crabs in the salt marsh. A study of the water drainage of the basins showed that this interaction does indeed modify the development of tidal creeks. Model dynamics would likewise follow different laws, which would provide a different formula for the probability of patch dilation. The patch shape can be obtained changing the pattern that dilates. 相似文献
40.
融冰季节北极破碎冰区热通量的初步研究 总被引:5,自引:1,他引:5
利用航空遥感数字影像的解析结果和实测气象,海洋和海冰资料,定量研究了夏季融冰期北极破碎冰区的热通量,计算了海洋对大气的热贡献,结果表明,在北极夏季海冰融化时,短波辐射远远大于感热和潜热通量,是表面热通量的决定因素,海洋对大气的热贡献主要由长波辐射决定,在观测期间,海洋对大气的热贡献为38~104Wm^-2,这部分热量的大小与海冰的密集度有关,当海冰密集度小于0.8时,海洋对大气的热贡献随海冰密度度的增大而减小,而当海冰密集度超过0.8以后,该热通量将随海冰密集度的增大而增大。 相似文献