现代日晕光度计多波段测光系统初步测试结果分析

Analysis of the Preliminary Measurements Taken by the Multi-Color Photometric System of the YNAO Sky Brightness Monitor

现代日晕光度计是用于精确测定监测址点的多种大气参量的精密仪器,它已列为我国西部太阳设备选址工作中的重要设备。利用同一架日晕光度计首先对昭通大山包进行了多波段数据采集。在仔细分析初步测光结果的基础上,进一步完善日晕光度计的光学系统。使用改进后的设备对昆明凤凰山址点进行了多次数据采集,都获得了理想数据。这表明日晕光度计的多波段测光系统已能够用于西部太阳选址工作中。

A modern Sky Brightness Monitor （SBM） is a precision instrument for measuring various atmospheric parameters. Such an SlqM has been listed as an important instrument in our site survey program in the west China. We have used an SBM to obtain multi-color sky brightness data at Mt. Dashanbao, Zhaotong. Based on our careful analysis of the preliminary photometric data, we have found ways to improve the optical system for the SBM. We have also tested the improved SBM by collecting data at the site of Fenghuang Mountain, Kunming for a few times. The data are of good quality showing that the multi-color photometric system of the SBM can be used for the site survey in the west China for solar observation. It should be noted that the data used to test the SBM were collected during the dry season of Yunnan （from the end of 2010 to the beginning of 2011 ）. The observational results show that the aerosol contents are ahnost same at the two sites indicating the atmospheric compositions of the two sites are stable. However, at Gaomeigu, Lijiang, the Rayleigh scattering effect weakens after high noon, and there is an obvious increase in aerosol content. There are significant differences among calibrated sky brightness intensities at Mt. Dashanbao, Fenghuang Mountain, and Gaomeigu. The average sky brightness intensity at Mt. Dashanbao is between 10ppm and 20ppm of the brightness of the solar disk center, that at Gaomeigu is about 10ppm, and that at Fenghuang Mountain is between 40ppm and 50ppm. These results objectively reflect the sky brightness intensities and atmospheric characteristics at different sites during a given period of time.