Statistics of turbulence profile at Cerro Tololo
Statistics of turbulence profile at Cerro Tololo
复制标题
托洛洛山湍流剖面统计
DOI：
10.1046/j.1365-8711.2003.06231.x
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发表时间：
2002
影响因子：
4.8
通讯作者：
J. Vasquez
中科院分区：
文献类型：
--
作者：
A. Tokovinin;S. Baumont;J. Vasquez
本文介绍了2002年5 - 7月在智利Cerro Tololo进行的连续3个月湍流剖面和观测监测的结果。新的MASS单星湍流监测仪测量了大约28000个低分辨率剖面，并伴有来自DIMM的观测数据。看到的中位数是0.95角秒。前500 m占总观测值的60%，自由大气观测值中位数为0.55弧秒。自由大气观测几乎不会超过0.15弧秒，因为在12公里以上总会有一些湍流。高空大气平静期为4天，自由大气能见度稳定为0.20.3弧秒。地面层自适应补偿的分辨率增益通常为1.7倍，在这种平静期为2-3倍。研究了自由大气湍流与对流层顶风速的关系以及地面湍流与地面风的关系。湍流的时间演变以反复爆发为特征，其典型持续时间从低层的15分钟增加到高层的1-2小时。大型湍流剖面数据库可用于验证天文观测的中尺度模拟。
Results of 3-month continuous monitoring of turbulence profile and seeing at Cerro Tololo (Chile) in May-July 2002 are presented. Some 28000 low-resolution profiles were measured by a new MASS single-star turbulence monitor, accompanied by seeing data from DIMM. The median seeing was 0.95 arcseconds. The first 500 m contribute 60% to the total seeing, the free-atmosphere median seeing was 0.55 arcseconds. Free-atmosphere seeing is almost never better than 0.15 arcseconds because there is always some turbulence above 12 km. A 4-day period of calm upper atmosphere with a stable free-atmosphere seeing of 0.20.3 arcseconds was noted. A gain in resolution from adaptive compensation of ground layer will be 1.7 times typically and 2-3 times during such calm periods. Correlations of the freeatmosphere turbulence with the wind speed at tropopause and of the ground-layer turbulence with ground wind are studied. Temporal evolution of turbulence is characterized by recurrent bursts, their typical duration increases from 15 minutes in low layers to 1-2 hours in high layers. The large data base of turbulence profiles can be used to test meso-scale modeling of astronomical seeing.