HU Yaning,LU Huiguo,LIU Yuxin,et al.Cloud Fraction Extraction Algorithm for an Independently-developed Sky Imager[J].Journal of Chengdu University of Information Technology,2023,38(04):410-413.[doi:10.16836/j.cnki.jcuit.2023.04.006]
自研制天空成像仪云量提取算法研究
- Title:
- Cloud Fraction Extraction Algorithm for an Independently-developed Sky Imager
- 文章编号:
- 2096-1618(2023)04-0410-04
- Keywords:
- sky imager; cloud fraction; Chengdu Plain
- 分类号:
- P413.21
- 文献标志码:
- A
- 摘要:
- 云在大气的能量分配、辐射传输、水循环以及极端天气的形成过程中有着不可忽视的作用。云量指云遮蔽天空的成数, 是云最重要的宏观物理特征之一, 对于云的研究具有重要意义。针对项目组成员自行研制的天空成像仪进行云量提取算法的开发和应用, 经过实验对比, 将天空成像仪拍摄图像根据灰度分为黑屏、较暗和较亮3类, 并基于分类结果采用传统红蓝比阈值法与全局阈值法相结合的方法进行云量提取。根据云量提取结果, 2021年成都地区云量年均值为0.69, 月均值0.55～0.85, 春夏季相较于秋冬季云量较低, 且云量日变化特征存在一定差异。
- Abstract:
- Clouds play an important role in the Earth-Atmosphere system, affecting the radiation budget, weather patterns, and global water cycle. Cloud Fraction(CF)is the percentage of a sky image that is covered with clouds, which is one of the key macro-physical parameters of cloud and has a significant influence on relative studies. In this study, the cloud fraction extraction algorithm was developed and applied to an independently-developed sky imager located in Chengdu.In this algorithm, sky images are divided into three categories: black, relatively gray, and relatively white, and detected by the Red/Blue Threshold method and/or Global Threshold method. The annual cloud fraction at Chengdu in 2021 is 0.69, and the monthly mean cloud fraction ranges from 0.55 to 0.85.The cloud fraction in spring and summer is relatively lower than that in autumn and winter, and there are differences in the diurnal variation characteristic in these two periods.
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备注/Memo
收稿日期:2023-03-01
基金项目:四川省科技厅资助项目(2022NSFSC1074)