西藏定日潜在亚毫米波天文台址资源调查

PRELIMINARY INVESTIGATION ON POTENTIAL SUBMILLIMETER ASTRONOMICAL SITES IN TING-RI, TIBET

由１９７０─１９８７年西藏定日无线电探空（气球）资料计算垂直大气水汽总含量，统计得到总含量小于１毫米的天数，海拔４３００米的定日县城为７７天／年，海拔５２８０米以上的美母山估计为１２０天／年以上，远好于世界上一流的亚毫米波、红外天文台址──夏威夷ＭａｕｎａＫｅａ的５８天／年。水汽含量小的冬春季，总云量也非常小，利于红外天文观测。美母山山顶平台面积达１平方千米，视野开阔，加上附近几个海拔５２００米以上的山头，是潜在的优良亚毫米天文观测台址。

For a good submillimeter site,it is important that the number of days per year with vertical atmospheric water vapour content (WVC≤1mm, above the site) should be large enough. By the statisties from the radio-sondage data recorded by the meteorological station of Ting-ri count (at an altitude of 4300m) in Tibet,the number there (WVC ≤1mm) is 77. Moreover there is a hill named Meimo Hill (at an altitude of 5280m) with a wide field of vision and a rather large flat area of 1 square kilometer in the region of Ting-ri.It has been reckoned that the number(WVC≤1mm)atMeimo Hill is larger than 120. In this respect, Ting-ri is much better than Mauna Kea which is a famous millimeter and infrared site in the world (see Table 3). Also the data in Fig. 6 show that the least water vapour content and cloud cover age in the region of Ting-ri concentrate in winter and spring. So Meimo Hill is possibly an excellent potential submillimeter site and advantageous too for infrared observation.