摘要:
500米口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST) ——“中国天眼”举世瞩目,是世界上最大的单口径射电望远镜。如果再建造几个 FAST 型大射电望远镜,开展联合观测,那么不仅可以进一步提高探测的灵敏度,也可以提高分辨率,从而拓展射电天文研究领域,这正是当前中国射电天文科学家的期盼,FAST型大射电望远镜选址洼地地形搜寻就是为实现这一期盼而开展的前期研究。当前,可以共享的地形数据数字高程模型(digital elevation model,DEM)资源已经实现洲际覆盖,且有不同的地面分辨率供选择; 计算机技术发展带来了地形数据 DEM 处理分析能力大大增强,处理技术不断创新,分析表达实现了可仿真。为此,通过比较分析阿雷西博射电望远镜(Arecibo radio telescope,Arecibo)和FAST 望远镜工程结构尺度、台址岩溶洼地地形的形态特点,提出 500 m口径望远镜的理想洼地地形条件; 在评价分析网络共享 DEM 地形数据的分辨率和数据质量的基础上,总结认为省级区域大射电望远镜选址以 30 m分辨率的 ASTER_GDEMV3 数据为宜; 在贵州全省大型洼地地形搜寻研究中,开发了基于 ArcGIS 平台提取洼地地形特征参数和拟合填挖方、叠合剖面等定量分析专题模块,归纳了应用 ArcGIS 主要工具搭建专题模块的关键步骤。研究结果解决了省级区域大型岩溶洼地地形搜寻中的关键技术,并提出了在实际工作中需要注意的几个问题。
关键词:
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选址
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岩溶洼地
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DEM
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地形参数
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填挖拟合
Abstract:
The Five-hundred-meter Aperture Spherical radio Telescope (FAST), also known as Tianyan (meaning the Eye of the Sky), has attracted worldwide attention and is the largest single-dish radio telescope in the world. The joint observations of FAST and several more FAST-type radio telescopes allow detection sensitivity and resolution to be further improved and the research fields to be expanded. Therefore, Chinese radio astronomy scientists have the expectation of building more FAST-type radio telescopes in China, which should be achieved based on the preceding research on depressions as the sites of FAST-type radio telescopes. Presently, the shared digital elevation model (DEM) data enjoy intercontinental coverage and different ground resolutions. The development of computer processing technology has greatly enhanced the processing and analysis capacities of DEM data and continuously innovated the processing technologies. Moreover, relevant analyses and expressions can be simulated. Therefore, based on a comparative analysis of the structural scales of the projects of the Arecibo radio telescope and the FAST, as well as the morphological characteristics of karst depressions, this study proposed the conditions of ideal depressions as the sites of FAST-type radio telescopes. Moreover, by analyzing the resolution and data quality of shared DEM data on the Internet, it is concluded that areas with ASTER_GDEMV3 data with a resolution of 30 m are suitable as sites of large radio telescopes in provincial-level regions. In search of large-scale depressions in Guizhou Province, this study developed special modules for quantitative analyses, such as extracting the characteristic parameters of depressions and the fitting of filling, excavation, and superimposed sections, based on the ArcGIS platform and summarized the key steps to organize and apply the major tools of ArcGIS in the special modules. The results of this study determined key technology in search of large Karst depressions in provincial-level regions. Furthermore, this study proposed several issues that are noteworthy in the application.
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