| 基于相机摄影测量的冰面反照率反演方法研究 |
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| 引用本文： | 刘俊峰,陈仁升,宋耀选,何晓波,王岗.基于相机摄影测量的冰面反照率反演方法研究[J].冰川冻土,2014,36(2):259-267. |
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| 作者姓名： | 刘俊峰 陈仁升 宋耀选 何晓波 王岗 |
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| 作者单位： | 中国科学院寒区旱区环境与工程研究所黑河上游生态-水文试验研究站,甘肃兰州730000;中国科学院寒区旱区环境与工程研究所内陆河流域生态水文重点实验室,甘肃兰州730000;中国科学院寒区旱区环境与工程研究所内陆河流域生态水文重点实验室,甘肃兰州730000;中国科学院寒区旱区环境与工程研究所黑河上游生态-水文试验研究站,甘肃兰州730000 |
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| 基金项目： | 中国科学院寒区旱区环境与工程研究所人才基金项目（Y251B21001）；国家自然科学基金项目（40771045；90702001）；中国博士后科学基金项目（2013M532095）资助 |
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| 摘 要： | 雪冰反照率是冰川与积雪能量平衡计算的关键参数,也是观测的难点.为测量冰面反照率,试验采用相机摄影测量技术,在祁连山十一冰川开展了自动拍摄、并利用共线方程进行冰川正射制图,在此基础上于2012年7月28日-8月18日在冰川表面开展了不同海拔梯度的反照率观测.通过统计分析晴天与阴天观测反照率与对应点相机拍摄获取的RGB归一化指数之间的关系,对十一冰川进行冰面反照率参数化方法研究.结果表明:晴天冰面反照率与RGB归一化指数存在明显的指数关系,拟合R2达到0.79;而阴天的统计关系较差,线性拟合R2仅为0.52.据此尝试利用晴天的拟合公式对整个冰面进行反照率参数化,计算表明:在晴天冰川表面地形阴影区的反照率存在低估现象,而无阴影区的反照率估算结果可信度较高.利用2013年的反照率观测数据进行了参数化方案的验证,结果表明:观测值与模拟值平均误差仅为0.037,表明利用RGB影像对反照率参数化具有一定的可用性和可靠性.
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| 关 键 词： | 相机摄影测量 雪冰 反照率 祁连山 十一冰川 |
| 收稿时间： | 2013-10-02 |
Glacier ice and snow surface albedo determined by using time-lapse camera photography |
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| LIU Junfeng,CHEN Rensheng,SONG Yaoxuan,HE Xiaobo,WANG Gang.Glacier ice and snow surface albedo determined by using time-lapse camera photography[J].Journal of Glaciology and Geocryology,2014,36(2):259-267. |
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| Authors: | LIU Junfeng CHEN Rensheng SONG Yaoxuan HE Xiaobo WANG Gang |
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| Institution: | 1. Qilian Alpine Ecology and Hydrology Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China;2. Key Laboratory of Ecohydrology of Inland River Basin, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China |
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| Abstract: | The snow and ice albedo plays a key role in the energy balance simulation but it is hard to observe in-situ. A time lapse camera for albedo estimation and its validation on the Shiyi Glacier in Qilian Mountain are described in this paper. The proposed technique involves from georeferencing oblique photographs to a digital elevation model. Once the image is georeferenced, statistical relationship will be established between normalized RGB values and corresponding albedo under clear sky and cloudy day, respectively. The normalized RGB values and albedo show a good exponential function relationship under clear day and the R2 of the empirical formula reaches to 0.79. Under cloudy day, the R2 of the empirical formula reaches to 0.52. This means that under clear day, the RGB values have good relationship with albedo. In this case, the parameterization of whole glacier surface is able to initiate. It is found that the outcome is good in flat surface, but underestimated on shadowed north-facing slopes. Finally the validation of the exponential function under clear sky (on 14 and 28 August of 2013) indicates that estimated and measured albedo values show good agreement and the mean variance is only 0.037, which means that the parameterization of albedo through normalized RGB values is credible and usable. |
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| Keywords: | time lapse camera snow and ice albedo Qilian Mountains Shiyi Glacier |
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