丽江高美古的二期选址——望远镜地面高度的确定

The Second Term Site Survey in Gaomeigu,Lijiang -Determination of the Ground-height for the Telescope

在丽江高美古前期选址工作的基础上[1～2],二期选址的望远镜地面高度的确定工作于2000年11月3日至2000年12月16日进行,采用30m铁塔的温度脉动测量装置,对6#选址观测点的近地面大气湍流进行反复多次测量,得到近地面不同高度(4～30m和8～22m)上每夜温度结构系数C2T的平均值,对观测取得的资料作进一步处理和分析,得到高美古6#观测点的望远镜地面高度为13～15m。

As a basic work of the site survey in Gaomeigu,Lijiang,we have determined the groundheight for the telescope by using microthermal sensors installed on a 30m meteorological tower at No.6 site of Gaomeigu.The microthermal sensors are installed at three levels of the tower and can be flexibly moved along the tower in terms of measured height.The measured principle is that the variation profile of the temperature structure parameter C2T along the groundheight determines the groundheight for the teleseope.The dada of C2T were collected over a twomonth period from November through December,2000.The ambient temperature,ground temperature,gas pressure,wind speed and direction were sampled in the same time.In order to maintain the reliability of the data,we kept microthermal sensors to be same sensitivity through adjusting their resistance at same groundheight.We obtained the data in 14 whole nights.The daily means of C2T were computed for different heights.The vertical profiles of C2T were then obtained by data regression.The groundheight of the telescope determined is 13-15m.