摘要
海冰是海洋环境监测的重点对象,光学遥感能为海冰的精细化监测提供技术支持,实现海冰的动态监测与量化估算。中国海洋水色业务卫星星座——海洋一号C/D卫星(Haiyang-1C/D,以下简称HY-1C/D),搭载有适用于海冰监测的海岸带成像仪CZI (Coastal Zone Imager)和水色水温扫描仪COCTS (Chinese Ocean Color and Temperature Scanner),具备开展海冰业务化监测应用的能力。本研究以2021年12月—2022年3月中国渤海辽东湾海冰为研究区,收集冰期内的HY-1C/D卫星影像数据,开展海冰识别与估算研究,评估CZI与COCTS数据对海冰的识别效能,分析海冰、海水、云等典型目标在光学(可见光—近红外)和热红外波段的影像特征;此外,针对光学遥感影像中海冰识别易受到云干扰问题,根据其在以上波段的遥感响应机理和图像特征差异,提出一种适用于HY-1C/D卫星在海冰分布区域的云掩膜方法,并对海冰进行精确提取;在识别基础上,进一步评估HY-1C/D卫星数据对于海冰密集度这一关键物理参数的光学遥感估算效能。结果表明:引入热红外波段,利用海冰和云的亮温差异对云进行掩膜,使得利用全局阈值提取海冰像元成为可能;通过对CZI、COCTS影像中海冰的高精度提取,进一步实现海冰密集度的估算,有效反映了像元中海冰和海水的混合程度,从而达到海冰海水像元解混的效果,提高海冰覆盖面积的估算精度。综上,本研究方法针对HY-1C/D卫星影像数据中的海冰识别提取具有较高的精度和抗干扰能力,可为国产海洋光学卫星的海冰监测业务化应用提供方法参考。
Sea ice represents a typical natural phenomenon that affects the marine and coastal environment in North China;thus,it is the focus of marine environment monitoring.Timely and accurate remote sensing data about sea ice is crucial for emergency treatment and recovery.Various remote sensing technologies have been applied to sea ice monitoring,with Sea Ice Concentration(SIC)serving as a key parameter indicating the spatial distribution characteristics of sea ice.Among these,optical remote sensing is frequently used.However,sea ice and different types of clouds(i.e.,cirrus and cumulus)have similar reflection characteristics in Visible and Near-Infrared(VNIR)wavelengths,thus posing great difficulties for the optical extraction of sea ice.Haiyang-1C/D(HY-1C/D)satellites are the first operational ocean color satellites of China,and both of them are equipped with a Coastal Zone Imager(CZI)and the Chinese Ocean Color and Temperature Scanner(COCTS),which can technically support the fine and dynamical monitoring of sea ice due to their wide coverage and high spatiotemporal resolution.In addition to the VNIR bands(412—865 nm),the onboard COCTS sensor can interpret the thermal characteristics of targets,which would help distinguish between sea ice and clouds.In this study,Liaodong Bay of the Bohai Sea is selected as the study area,and synchronous CZI and COCTS images covering Liaodong Bay from December 2021 to March 2022 are collected and analyzed.The main objective of this study is to verify the feasibility of HY-1C/D satellites to detect sea ice,especially the image characteristics of typical targets(i.e.,sea ice,seawater and clouds)in optical(i.e.,VNIR)and thermal infrared bands.Using the Brightness Temperature(BT)difference between sea ice and cloud in the thermal infrared band of COCTS,sea ice and cirrus clouds can be preliminarily separated.However,the difference in BT between sea ice and cumulus clouds is minimal,which can be further separated in accordance with the NIR-red reflectance ratio.In addition to the sea ice identification,the application of SIC can effectively unmix icewater pixels and improve the estimation accuracy of the sea ice coverage area for optical images with different spatial resolutions.The above results can confirm the capability of HY-1C/D satellites in sea ice detection.Therefore,HY-1C/D satellites can provide reliable data and improve the monitoring of sea ice.
作者
李玲
锁子易
石立坚
王卿
焦俊男
唐君
陆应诚
LI Ling;SUO Ziyi;SHI Lijian;WANG Qing;JIAO Junnan;TANG Jun;LU Yingcheng(International Institute for Earth System Science,Nanjing University,Nanjing 210023,China;Collaborative Innovation Center of South China Sea Studies,Nanjing University,Nanjing 210093,China;National Satellite Ocean Application Center,Beijing 100081,China;College of Harbour and Coastal Engineering,Jimei University,Xiamen 361021,China)
出处
《遥感学报》
北大核心
2025年第4期897-909,共13页
NATIONAL REMOTE SENSING BULLETIN
基金
国家重点研发计划(编号:2021YFC2803301)
国家自然科学基金(编号:42371380,42071387)。
关键词
海洋一号C/D卫星
海冰
光谱特征
亮温
云检测
海冰密集度
HY-1C/D satellites
sea ice
spectral features
brightness temperature
cloud detection
Sea Ice Concentration(SIC)
