A Satellite Survey of Cloud Cover and Water Vapor in
A Satellite Survey of Cloud Cover and Water Vapor in
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云量和水汽的卫星调查
DOI：
10.1117/12.788264
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发表时间：
2001
影响因子：
2.2
通讯作者：
N. Chile
中科院分区：
文献类型：
--
作者：
N. Chile
由于红外波长的高透明度，智利阿塔卡马的Chajnantor公司（海拔5，650米）是世界上最有前途的红外天文学站点之一。为了定量评估场地条件，我们从2006年4月至2007年4月进行了天气和云发射率监测活动。地面状况如风向、风速、气温和湿度由安装在山顶的气象站监测。云的发射率是通过全天红外相机每五分钟拍摄一次的中红外天空图像来估计的，每天24小时。结果总结如下。1)山顶的天气条件比潘帕拉博拉高原的条件略严酷。最大风速为35米/秒，最低温度约为-10度。2)一年中“晴朗+可用”天气的比例（定义为云发射率< 10%）为82%。在玻利维亚冬季，这一比例下降到40-50%，4月至7月增加到90%以上。这是可比的，甚至比其他天文网站更好。
Because of the high transparency in infrared wavelength, Co. Chajnantor (5,650 m altitude) at Atacama, Chile, is one of the most promising sites for infrared astronomy in the world. For evaluating the site condition quantitatively we carried out weather and cloud emissivity monitoring campaign from April 2006 to April 2007. The ground-level condition such as wind direction, wind speed, air temperature, and humidity was monitored by a weather station installed at the summit. Cloud emissivity was estimated by mid-infrared sky images taken by a whole-sky infrared camera every five minutes for 24 hours a day, every day. Results are summarized as followings. 1) The weather condition at the summit is slightly harsher than the condition at the Pampa la Bola plateau. Maximum speed of the wind is 35m/s, and minimum temperature is about-10 degree. 2) Fraction of" clear+ usable" weather (which is defined as the cloud emissivity< 10%)" is 82% in a year. The fraction decrease to 40-50% on Bolivian winter season, and increases to over 90% from April to July. This is comparable or even better than the other astronomical sites.