选址与日冕观测组知识库

地理信息是地面望远镜天文选址研究中的重要内容.尤其是对现有地理信息系统(Geographic Information System,GIS)的有效利用,已成为现代选址中远程分析阶段最重要的手段之一.天文址点的考虑在地理条件上应遵循以下原则:相对落差较大、交通可行、尽量远离人口集中的区域.从未来建站维护和人员长期驻站的角度考虑,天文址点以海拔处于3000～5000 m的范围、距离城镇大本营1 h左右车程为最佳.以云南省大姚县百草岭地区为选址研究对象,展示了GIS数据处理能够为全面了解一个候选区域3维地形地貌、江川河流、道路村落、电力分布以及预测该地区未来人口和城市化发展趋势等方面内容提供准确、直观、定量的参考数据.通过基于GIS数据的科学分析,发现海拔3 600多米的大百草岭山顶平坦而又干旱、周围人口稀少、道路便利、无工厂污染源,是地方政府重要自然保护区;它与直线距离10 km外的乡镇之间的相对落差超过了1 500 m,与50km外的县城的相对落差达到1 800 m,是滇中彝州坝区一座名副其实的孤峰.因此,GIS数据分析对于远程选址十分有益,GIS技术是现代天文选址不可或缺的重要手段.

The geographic information is of great importance for the site survey of ground-based telescopes. Especially, an effective utilization of the geographic information system (GIS) has been one of the most significant methods for the remote analysis of modern site survey. The astronomical site survey should give consideration to the following geographical conditions: a large relative fall, convenient traffic conditions, and far away from populated areas. Taking into account of the convenience of construction and maintenance of the observatories as well as the living conditions of the scientists-inresidence, the optimum candidate locations may meet the conditions to be at a altitude between 3000 m and 5000 m and within one-hour drive from villages/towns. In this paper, as an example, we take the regions of the Great Baicao mountain ridge at Dayao county in Yunnan province to research the role of the GIS for site survey task. The results indicate that the GIS can provide accurate and intuitive data for us to understand the three dimensional landforms, rivers, roads, villages, and the distributions of the electric power as well as to forecast the tendency of the population and city development around. According to the analysis based on the GIS, we find that the top of the Great Baicao mountain ridge is flat and droughty. There are few inhabitants to distribute around the place while the traffic conditions are convenient. Moreover, it is a natural conservation area protected by the local government, and no industry with pollution sources exists in this region. Its top is 1500 m higher than the nearby village 10 km away, and 1800 m higher than the town center 50 km away. The Great Baicao mountain ridge is definitely an isolated peak in the area of the Yi nationality of Yunnan. Therefore, the GIS data analysis is a very useful for the remote investigation stage for site survey, and the GIS is the indispensable source for modern astronomical site survey.