中文摘要：

夜天光亮度监测对专业天文台是一项重要的、基础性的工作，为天文观测提供重要的参考，同时为衡量现代城市光污染程度评估提供依据．已有研究表明，拉萨及周边地区具有得天独厚的天文观测条件，加之工业化程度低，大气污染较轻，在大气视宁度、大气透明度等指标方面优于中国大部分地区．采用2015年9月在西藏拉萨市羊八井国际宇宙线观测站和西藏大学新校区安装的2台SQM-LE型夜天光监测仪长期监测这2个区域的夜天光背景，初步分析了羊八井观测站1a（2015．12-2016．11）的夜天光监测结果，给出了羊八井观测站晴朗有月夜、晴朗无月夜的夜天光亮度水平，并总结了夜天光亮度的日变化、晴朗无月夜月变化情况．

英文摘要：

The monitoring of night sky brightness （NSB） is an important and fundamental work for as- tronomical observatory and night reserve. It also provides a fundamental assessment for some measures of modern urban light pollution. Studies have shown that Lhasa and the surrounding areas have an advantage over most domestic areas in astronomical observation owing to atmospheric seeing,atmospheric transparen- cy,less atmospheric pollution and industrialization. However, so far, Lhasa and the surrounding areas ha- ven＇t any accumulation of data for NSB monitoring. In view of this,two SQM-LE type sky quality monitors were installed in september 2015 at Yangbajing international cosmic ray observatory and Tibet university. Based on the past year＇s （2015.11-2016.12）data,the NSB of clear moonless night and full moon night, daily variation,monthly variation were given. The results show that, the Yangbajing observatory is propi- tious to astronomical observation.