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近几十年,随着卫星测高技术和相关数据精密处理技术发展,依托卫星测高技术业已成为快速获取全球海底地形数据的可靠手段,国内外相关组织机构已发布了一系列全球海底地形模型。整理评述了多款全球海底地形的基本情况,以及相互间的内在联系,包括DBDB系列模型、ETOPO系列模型、Sandwell系列模型、GEBCO系列模型、SRTM+系列模型、EARTH地形球谐系数模型、BAT_VGG模型、BAT_WHU2020模型、STO_IEU2020模型等。通过对全球海底地形模型的认识和梳理,以期为下一步全球海底地形模型高效、低成本构建提供方法参考。 相似文献
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栅格小于1′的全球海底地形数据通常以卫星测高海洋重力数据构建的1′海底地形数据作为背景场模型,采用数据格网化方法得到。基于此,以STO_IEU2020模型作为海底地形背景场数据,使用反距离加权法、改进Shepard拟合方法、径向基函数法、Kriging方法4种常规网格化方法以及“移去-恢复”方法,分别构建了试验区域栅格大小为30″和15″海底地形模型,并对试验结果开展了分析评估。试验结果表明,采用改进Shepard拟合方法构建的30″和15″栅格海底地形模型相较其他3种常规海底地形格网化方法检核精度高。进一步基于改进Shepard网格化方法,采用“移去-恢复”方法构建的30″和15″栅格海底地形模型结果显示,“移去-恢复”方法可进一步提升建模精度,据此建议制作多尺度海底地形数据,可重点考虑基于“移去-恢复”的改进Shepard拟合方法。 相似文献
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海底地形和海洋重力场在一定波段频率域上存在相关性,传统海底地形反演方法主要考虑海底地形与重力数据之间的线性关系,而忽略非线性项作用对反演结果的影响。基于此,提出了基于海底地形单元分区的BP神经网络反演方法,改善海底地形反演精度。选取东印度洋北部东经90°海岭附近海域(83°E~92°E,10°S~10°N)为实验区,利用船测水深、卫星测高重力等数据,根据地形特征将实验区分为海盆区和海岭区,使用BP神经网络方法分别进行海底地形反演,构建了实验区1′×1′局部海底地形模型。结果表明,基于地形单元分区的反演结果模型平均相对误差精度可达1.45%,比未分区的反演结果均方根误差降低了42 m,验证了本文方法的有效性和可行性。 相似文献
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W. S. D. Wilcock D. R. Toomey G. M. Purdy S. C. Solomon 《Marine Geophysical Researches》1993,15(1):1-12
We present a gridded Sea Beam bathymetric map of a 5100 km2 area between 9° and 10° N on the East Pacific Rise (included as a color separate accompanying this issue). The raw bathymetric data are renavigated using a technique for calculating smooth adjustments to navigation that incorporates absolute constraints from satellite fixes and acoustically-located explosive shots, and relative constraints from the misfit of bathymetric data at ship track crossovers. We describe a back-projection technique for gridding the bathymetric data that incorporates an approximation for the power distribution within a narrow-beam echo sounding system and accounts for the variable uncertainties associated with multi-beam data. The nodal separation of the resulting map is ~ 80 m in both latitude and longitude, and the sampling of grid points within a 60 × 85 km2 region is in excess of 99%. A formal analysis of variance is applied to the gridded bathymetric data. For each grid point, the difference between the variance of data from within a track versus data from between tracks provides an upper bound on the magnitude of bathymetric misfits arising from navigational errors. The renavigation results in an 88% reduction in this quantity. We also examine the effects of renavigation on the misfit of magnetic and gravity data at crossovers and compare our results with other bathymetric surveys. A striking feature of the final bathymetric map is the sinuous regional shape of the rise axis. In plan view, the local trend of morphology sometimes varies by up to 15° and the distances separating changes in morphological trend are about 10–20 km. In cross section the slopes of the rise flanks are notably asymmetric and show some correlation with the offset of the axial magmatic system as detected by seismic methods. 相似文献
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Capabilities of the bathymetric Hawk Eye LiDAR for coastal habitat mapping: A case study within a Basque estuary 总被引:1,自引:0,他引:1
Guillem Chust Maitane Grande Ibon Galparsoro Adolfo Uriarte Ángel Borja 《Estuarine, Coastal and Shelf Science》2010
The bathymetric LiDAR system is an airborne laser that detects sea bottom at high vertical and horizontal resolutions in shallow coastal waters. This study assesses the capabilities of the airborne bathymetric LiDAR sensor (Hawk Eye system) for coastal habitat mapping in the Oka estuary (within the Biosphere Reserve of Urdaibai, SE Bay of Biscay, northern Spain), where water conditions are moderately turbid. Three specific objectives were addressed: 1) to assess the data quality of the Hawk Eye LiDAR, both for terrestrial and subtidal zones, in terms of height measurement density, coverage, and vertical accuracy; 2) to compare bathymetric LiDAR with a ship-borne multibeam echosounder (MBES) for different bottom types and depth ranges; and 3) to test the discrimination potential of LiDAR height and reflectance information, together with multi-spectral imagery (three visible and near infrared bands), for the classification of 22 salt marsh and rocky shore habitats, covering supralittoral, intertidal and subtidal zones. The bathymetric LiDAR Hawk Eye data enabled the generation of a digital elevation model (DEM) of the Oka estuary, at 2 m of horizontal spatial resolution in the terrestrial zone (with a vertical accuracy of 0.15 m) and at 4 m within the subtidal, extending a water depth of 21 m. Data gaps occurred in 14.4% of the area surveyed with the LiDAR (13.69 km2). Comparison of the LiDAR system and the MBES showed no significant mean difference in depth. However, the Root Mean Square error of the former was high (0.84 m), especially concentrated upon rocky (0.55–1.77 m) rather than in sediment bottoms (0.38–0.62 m). The potential of LiDAR topographic variables and reflectance alone for discriminating 15 intertidal and submerged habitats was low (with overall classification accuracy between 52.4 and 65.4%). In particular, reflectance retrieved for this case study has been found to be not particularly useful for classification purposes. The combination of the LiDAR-based DEM and derived topographical features with the near infrared and visible bands has permitted the mapping of 22 supralittoral, intertidal and subtidal habitats of the Oka estuary, with high overall classification accuracies of between 84.5% and 92.1%, using the maximum likelihood algorithm. The airborne bathymetric Hawk Eye LiDAR, although somewhat limited by water turbidity and wave breaking, provides unique height information obscured from topographic LiDAR and acoustic systems, together with an improvement of the habitat mapping reliability in the complex and dynamic coastal fringe. 相似文献
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DGPS(DifferentialGlobalPositioningSystem)测量技术即差分定位技术,包括实时差分和后处理差分定位技术,正在远海和近海测量中得到广泛应用。后处理差分定位与微波定位及GPS实时差分定位相比,具有作用距离远,不受基准台与船台之问的障碍物影响以及减少基准台等优点。对于近海大比例尺(大于1:1万)测量,可采用实时差分定位的方法,而小于1:1万中小比例尺海底地形图测绘及海上其他工程测量,采用后处理差分定位,既能满足精度要求,又能提高工作效率。本文主要介绍利用DGPS后处理定位方法,在测绘广西沿海1:5万海底地形图中的应用情况。 相似文献
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河道的防洪预警模拟及其三维地形可视化 总被引:1,自引:0,他引:1
运用数字高程模型(DEM)数据格式中的三角网格模型,以OpenGL提供的光照、材质、纹理映射和反走样等技术实现河道地形的三维可视化;利用VC 及OpenGL中的平移、旋转和缩放等功能,实现河道流场三维显示的效果。在读取相关洪水数据的情况下,实现了流场可视化及河道堤坝防洪预警等相关查询功能,为防洪决策提供了相关的参考。 相似文献