冰、云和陆地高程卫星2号(ice,cloud and land elevation satellite-2,ICESat-2)搭载了先进地形激光测高系统(advanced topographic laser altimeter system,ATLAS),该系统采用光子计数探测模式,可获取高精度的地表高程信息。ATLAS使用5...冰、云和陆地高程卫星2号(ice,cloud and land elevation satellite-2,ICESat-2)搭载了先进地形激光测高系统(advanced topographic laser altimeter system,ATLAS),该系统采用光子计数探测模式,可获取高精度的地表高程信息。ATLAS使用532 nm波段激光器,具备一定的水深探测能力,为星载数据近岸水深探测提供了新手段。利用ICESat-2ATLAS数据进行测深,关键问题是如何实现不同区域、不同环境、不同密度分布条件下信号光子的自动探测与提取。为解决此问题,提出了一种基于自适应空间滤波的ICESat-2数据测深方法,该方法首先将水面以上、水面和水下区域的原始光子进行分离,随后基于可变椭圆密度滤波核精确提取水面与水底光子,椭圆密度滤波核参数根据不同水深下光子密度的分布特点自适应确定,最终实现浅海水深测量。实验结果表明,所提方法获取的ICESat-2测深结果与机载激光雷达测深结果的相关系数达到0.93,均方根误差为0.51 m,具有较高的测深精度。展开更多
重复轨道法是利用测高卫星监测南极冰盖高程变化的重要方法。在利用重复轨道方法计算冰盖高程变化时,引入一种基于抗差估计的方法(insrtitue of geodesy and geophysicsⅢ,IGG Ⅲ)取代传统的最小二乘方法(least square,LS)。利用2019年...重复轨道法是利用测高卫星监测南极冰盖高程变化的重要方法。在利用重复轨道方法计算冰盖高程变化时,引入一种基于抗差估计的方法(insrtitue of geodesy and geophysicsⅢ,IGG Ⅲ)取代传统的最小二乘方法(least square,LS)。利用2019年3月至2021年12月的ICESat-2陆冰高程数据,分别采用LS方法和IGG Ⅲ方法在东南极Totten冰川流域进行了实验。结果表明,该流域分别呈现出-0.038±0.163 m/yr和-0.040±0.136 m/yr的高程降低趋势,说明IGG Ⅲ抗差估计方法能够在保留重复轨道方法高数据利用率的基础上,有效地减少异常数据被错误引入产生的误差。利用MEaSUREs ITS_LIVE高程变化产品对两种方法计算的结果进行了对比,IGG Ⅲ方法的结果在空间分布上具有更好的一致性。展开更多
ICESat-2(Ice,Cloud and Land Elevation Satellite 2)卫星激光雷达数据被广泛应用于地形地貌测绘、森林监测、水域监测等多个领域。当ICESat-2飞越海面时,可以检测到被海面反射回的微弱光子信号,其反映了海面的起伏状态,但同时也包含...ICESat-2(Ice,Cloud and Land Elevation Satellite 2)卫星激光雷达数据被广泛应用于地形地貌测绘、森林监测、水域监测等多个领域。当ICESat-2飞越海面时,可以检测到被海面反射回的微弱光子信号,其反映了海面的起伏状态,但同时也包含了设备噪声、大气颗粒散射噪声、背景干扰噪声等大量噪声光子。本研究提出了一种新的海面信号光子提取和海浪要素反演方法,首先将原始ICESat-2数据沿垂直方向均匀分段,统计各段内光子数,对其进行高斯拟合和迭代中值滤波,确定精确的海面光子上下界,从而提取出海面信号光子。进一步采用支持向量回归拟合,提取瞬时海面轮廓。在此基础上,利用频谱分析方法计算出有效波高和初步海浪峰值波长,通过对同步的强弱激光束相位相干分析,估算海浪波向,并修正海浪峰值波长和计算海浪峰值周期。对来自好望角和萨摩亚海域的24条轨道ICESat-2数据进行海面光子提取和海浪要素反演,并将结果与ERA5再分析数据进行对比验证。结果表明,海浪有效波高、波向和峰值周期的均方根误差(RMSE)分别为0.12 m、28.58°和0.48 s,表明该方法具有较高的海浪要素反演精度,具备进一步探索更大范围激光雷达数据海浪要素提取和分析的潜力。展开更多
Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier...Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.展开更多
ICESat-2激光测高卫星首次将微脉冲多波束光子计数激光雷达技术应用于卫星平台,具有多波束、高精度测量等优势,在科学研究和实际应用中具有广阔前景。本文以2011年1月至2024年7月中国知网数据库和Web of Science(WOS)核心合集数据库的...ICESat-2激光测高卫星首次将微脉冲多波束光子计数激光雷达技术应用于卫星平台,具有多波束、高精度测量等优势,在科学研究和实际应用中具有广阔前景。本文以2011年1月至2024年7月中国知网数据库和Web of Science(WOS)核心合集数据库的文献为样本,借助文献计量学方法,利用CiteSpace.6.3.R3软件,分析了ICESat-2激光测高卫星研究的国内外发文量变化规律。通过对国内外期刊发文量、关键词、研究热点进行可视化分析和对比分析,揭示了ICESat-2激光测高卫星研究领域的热点和发展趋势,以为相关研究提供参考。展开更多
文摘ICESat-2(Ice,Cloud and Land Elevation Satellite 2)卫星激光雷达数据被广泛应用于地形地貌测绘、森林监测、水域监测等多个领域。当ICESat-2飞越海面时,可以检测到被海面反射回的微弱光子信号,其反映了海面的起伏状态,但同时也包含了设备噪声、大气颗粒散射噪声、背景干扰噪声等大量噪声光子。本研究提出了一种新的海面信号光子提取和海浪要素反演方法,首先将原始ICESat-2数据沿垂直方向均匀分段,统计各段内光子数,对其进行高斯拟合和迭代中值滤波,确定精确的海面光子上下界,从而提取出海面信号光子。进一步采用支持向量回归拟合,提取瞬时海面轮廓。在此基础上,利用频谱分析方法计算出有效波高和初步海浪峰值波长,通过对同步的强弱激光束相位相干分析,估算海浪波向,并修正海浪峰值波长和计算海浪峰值周期。对来自好望角和萨摩亚海域的24条轨道ICESat-2数据进行海面光子提取和海浪要素反演,并将结果与ERA5再分析数据进行对比验证。结果表明,海浪有效波高、波向和峰值周期的均方根误差(RMSE)分别为0.12 m、28.58°和0.48 s,表明该方法具有较高的海浪要素反演精度,具备进一步探索更大范围激光雷达数据海浪要素提取和分析的潜力。
基金supported by the National Key Research and Development Program of China under grant numbers 2023YFC2809103 and 2024YFC2813505the National Natural Science Foundation of China under the grant number 41706216+2 种基金the Fundamental Research Funds for the Central Universities under grant numbers 2042022kf1204,2042022kf1069,2042023gf0012,2042022dx0001the Hubei Provincial Natural Science Foundation of China under grant number 2022CFB081the State Key Laboratory of Geodesy and Earth's Dynamics,Innovation Academy for Precision Measurement Science and Technology under grant number SKLGED2023-2-6。
文摘Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.
文摘ICESat-2激光测高卫星首次将微脉冲多波束光子计数激光雷达技术应用于卫星平台,具有多波束、高精度测量等优势,在科学研究和实际应用中具有广阔前景。本文以2011年1月至2024年7月中国知网数据库和Web of Science(WOS)核心合集数据库的文献为样本,借助文献计量学方法,利用CiteSpace.6.3.R3软件,分析了ICESat-2激光测高卫星研究的国内外发文量变化规律。通过对国内外期刊发文量、关键词、研究热点进行可视化分析和对比分析,揭示了ICESat-2激光测高卫星研究领域的热点和发展趋势,以为相关研究提供参考。
