基于船基图像的北极冰面融池形态研究  

Study on the morphology of Arctic melt pond based on ship-based images

作　　者：邵华伟 周嘉儒 王庆凯[1] 张航 卢鹏[1] 李志军[1] SHAO Huawei;ZHOU Jiaru;WANG Qingkai;ZHANG Hang;LU Peng;LI Zhijun(State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《冰川冻土》2024年第2期502-512,共11页Journal of Glaciology and Geocryology

基　　金：国家重点研发计划项目(2022YFE0107000);国家自然科学基金项目(41922045);辽宁省“兴辽英才计划”项目(XLYC2007033)资助。

摘　　要：基于中国第12次北极科学考察期间获取的船侧倾斜拍摄海冰图像,研究了北极冰面融池大小和形态参数的空间分布及统计特征。应用自动检测算法将图像划分为水、冰、融池三种表面类别,经倾斜校正后计算每种类别的面积分数及单个融池的大小和形态。结果显示,融池的面积分数随纬度升高先增大后减小,较短的融化时间和较早的再冻结导致高纬度地区融池面积分数一直较低。融池的面积、周长和平均钳测直径随纬度升高具有相似变化规律,均为先增大后减小。不同大小融池面积的频率分布与幂律函数相吻合,对应指数均在1.4~1.8范围内,具有一定相似性。融池的分形维数随纬度升高分布较均匀,而周长与面积比值随纬度变化较大。不同纬度融池边缘凸度与圆形的对应值π相差较大,而各纬度融池圆度平均值为2.39±0.23;融池圆度和凸度与其面积成正比,周长与面积比值则与融池面积成反比,表明融池边缘随着融池面积增加而变得更长更曲折。冰面融池变化引起的平均海表反照率空间差异较大,随着纬度升高在0.24~0.67之间变化,变化率为0.10(°N)^(-1)。本文研究的融池大小和形态参数可为融池演变模拟及遥感反演算法改进提供重要观测依据和地面验证。With global warming,Arctic temperature is increasing,and melt pond has become an important feature of Arctic sea ice.Due to the positive feedback of ice surface albedo,sea ice is melting rapidly,and thus the size and shape of melt pond are very important for the simulation of Arctic sea ice change and further for the validation of existing remote sensing algorithms.In the present study,6103 images of sea ice were obtained onboard the icebreaker R/V Xuelong 2 during the 12th Chinese National Arctic Research Expedition,5489 of them remain after excluding invalid images such as uneven illumination and blurring,and then the spatial distribution and statistical characteristics of melt pond size and morphological parameters are investigated.The watershed algorithm is applied to segment the images into 9 uniform copies,and the random forest algorithm classifies the segmented images and creates a training set.Each image is classified into three surface categories including water,ice,and melt pond by the automated method,and the area fraction of each category as well as the size and shape of individual melt pond is calculated after tilt correction.The results show that the area fraction of melt pond increases and then decreases with increasing latitude,and the area fraction of ponded ice decreases with increasing latitude.The shorter melting time and earlier refreezing result in lower area fraction of melt pond at higher latitudes.The area,perimeter,and mean clamp diameter of the melt pond have similar patterns of change with increasing latitude.All of them rise first and then drop,indicating that the parameters of melt pond size have good consistency.The median value of melt pond area is significantly lower than the mean value indicating that there are more relatively small melt ponds.The frequency distribution of different sizes of melt pond areas is consistent with the power-law function,and the indices fitted to different observations are in the range of 1.4~1.8,with some similarity.The fractal dimension of the melt p

关 键 词：融池 形态参数 船基图像 空间分布 北极海冰 

分 类 号：P941.62[天文地球—自然地理学] P731.15