在利用对地学激光测高系统(the Ice,Cloud and land Elevation-Geoscience Laser Altimeter System)数据估测森林结构参数时,需对原始波形进行去噪处理,以提高估测精度。以吉林汪清林区为例,提出了基于窗函数的林区GLAS数据消噪方法,选...在利用对地学激光测高系统(the Ice,Cloud and land Elevation-Geoscience Laser Altimeter System)数据估测森林结构参数时,需对原始波形进行去噪处理,以提高估测精度。以吉林汪清林区为例,提出了基于窗函数的林区GLAS数据消噪方法,选取了5种窗函数对GLAS数据进行消噪并比较其消噪精度。结果表明:窗函数对林区波形数据消噪具有较好的效果,窗函数消噪法的信噪比SNR最高为40.488 679,均方根误差RMSE最低为0.000 335;GLAS数据经窗函数消噪后能够合理地预测林区冠层高度,预测冠层高度与实测冠层高度的回归精度r从0.725增至0.820;本研究所选的几种窗函数中布拉克曼窗函数的消噪效果较好。结果说明了窗函数在对ICESat-GLAS波形数据消噪中具有很大的应用潜力。展开更多
激光测高卫星在获取全球高程控制点方面具有独特的优势,本文针对ICESat(Ice,Cloud and land Elevation Satellite)卫星上搭载的地球激光测高系统GLAS(Geo-science Laser Altimetry System),提出了一种多准则约束的高程控制点筛选算法。...激光测高卫星在获取全球高程控制点方面具有独特的优势,本文针对ICESat(Ice,Cloud and land Elevation Satellite)卫星上搭载的地球激光测高系统GLAS(Geo-science Laser Altimetry System),提出了一种多准则约束的高程控制点筛选算法。算法综合利用全球公开版的SRTM(Shuttle Radar Topography Mission)DEM数据对GLAS进行粗差剔除,然后利用GLA14产品中的云量、姿态质量标记、饱和度参数、增益参数等多种与测距有关的属性参数进行粗粒度的筛选,保留受云层、大气、地表反射率等影响较小的激光足印点,最后结合GLA01的波形特征参数做进一步精细筛选,提取出高精度的激光点作为高程控制点。本文还采用天津、河北两个实验区的数据,利用高精度的DEM成果数据对筛选的结果进行了验证。实验结果表明,经多准则约束筛选后的激光足印点具有很高的高程精度,能够作为1∶50000甚至1∶10000立体测图时的高程控制点使用,研究结论可为国产高分辨率卫星在境外地区进行无地面控制点的立体测图提供参考。展开更多
北极海冰变化受全球气候变化影响明显,海冰的变化不仅体现在面积上,而且也体现在厚度上。利用海冰干舷高度可以反演海冰厚度,冰、云和陆地高程卫星/地球科学激光测高系统（ice,cloud and land elevation satellite/geoscience laser alt...北极海冰变化受全球气候变化影响明显,海冰的变化不仅体现在面积上,而且也体现在厚度上。利用海冰干舷高度可以反演海冰厚度,冰、云和陆地高程卫星/地球科学激光测高系统（ice,cloud and land elevation satellite/geoscience laser altimeter system,ICESat/GLAS）提供了高精度的海冰高程信息。利用ICESat/GLAS测高数据,提取了2003～2008年部分时间段北极区域海冰的干舷高度,分析了2003～2008年间北极海冰季节性以及年际变化特征。结果表明,北极海冰干舷高度呈下降趋势,并且在2007年夏季减少趋势最为明显。对北极海冰在2007年迅速减少的原因进行了探讨,并利用仰视声呐实测数据对干舷高提取算法存在的系统性偏差进行了讨论与分析。展开更多
Dome A, the highest dome of East Antarctic Ice Sheet, is being an area focused by international Antarctic community after Chinese Antarctic Expedition finally reached there in 2005, and with the ongoing International ...Dome A, the highest dome of East Antarctic Ice Sheet, is being an area focused by international Antarctic community after Chinese Antarctic Expedition finally reached there in 2005, and with the ongoing International Polar Year （IPY） during August 2007. In this paper two data processing methods are used together to generate two 100-m cell size digital elevation models （DEMs） of the Dome A region （Dome A-DEM） by using Cokriging method to interpolate the ICESat GLAS data, with Ihde-DEM as a constraint. It provides fundamental data to glaciological and geophysical investigation in this area. The Dome A-DEM was applied to determining the ice-sheet surface elevations and coordinates of the south and north summits, defining boundaries of basins and ice ftowlines, deducing subglacial topography, and mapping surface slope and aspect in Dome A region. The DEM shows there are two （north and south） summits in Dome A region. The coordinate and the surface elevation of the highest point （the north summit） are 80°21＇29.86＂S, 77°21＇50.29＂E and 4092.71±1.43m, respectively. The ice thickness and sub-ice bedrock elevation at north summit are 2420m and 1672m, respectively. Dome A region contains four drainage basins that meet together near the south summit. Ice ftowlines, slope and aspect in detail are also derived using the DEM.展开更多
The Amery Ice Shelf is the largest ice shelf in East Antarctica. A new DEM was generated for this ice shelf, using kriging to interpolate the data from ICE- Sat altimetry and the AIS-DEM. The ice thickness distributio...The Amery Ice Shelf is the largest ice shelf in East Antarctica. A new DEM was generated for this ice shelf, using kriging to interpolate the data from ICE- Sat altimetry and the AIS-DEM. The ice thickness distribution map is converted from the new DEM, assuming hydrostatic equilibrium. The Amery Ice Shelf marine ice, up to 230 m thick, is concentrated in the northwest of the ice shelf. The volume of the marine ice is 2.38 × 10^3 km^3 and accounts for about 5.6% of the shelf volume.展开更多
文摘在利用对地学激光测高系统(the Ice,Cloud and land Elevation-Geoscience Laser Altimeter System)数据估测森林结构参数时,需对原始波形进行去噪处理,以提高估测精度。以吉林汪清林区为例,提出了基于窗函数的林区GLAS数据消噪方法,选取了5种窗函数对GLAS数据进行消噪并比较其消噪精度。结果表明:窗函数对林区波形数据消噪具有较好的效果,窗函数消噪法的信噪比SNR最高为40.488 679,均方根误差RMSE最低为0.000 335;GLAS数据经窗函数消噪后能够合理地预测林区冠层高度,预测冠层高度与实测冠层高度的回归精度r从0.725增至0.820;本研究所选的几种窗函数中布拉克曼窗函数的消噪效果较好。结果说明了窗函数在对ICESat-GLAS波形数据消噪中具有很大的应用潜力。
文摘北极海冰变化受全球气候变化影响明显,海冰的变化不仅体现在面积上,而且也体现在厚度上。利用海冰干舷高度可以反演海冰厚度,冰、云和陆地高程卫星/地球科学激光测高系统（ice,cloud and land elevation satellite/geoscience laser altimeter system,ICESat/GLAS）提供了高精度的海冰高程信息。利用ICESat/GLAS测高数据,提取了2003～2008年部分时间段北极区域海冰的干舷高度,分析了2003～2008年间北极海冰季节性以及年际变化特征。结果表明,北极海冰干舷高度呈下降趋势,并且在2007年夏季减少趋势最为明显。对北极海冰在2007年迅速减少的原因进行了探讨,并利用仰视声呐实测数据对干舷高提取算法存在的系统性偏差进行了讨论与分析。
基金Under the auspices of the National Natural Science Foundation of China (No. 40471028, No. 40476005)ShanghaiShu Guang Project (No. 05SG46)
文摘Dome A, the highest dome of East Antarctic Ice Sheet, is being an area focused by international Antarctic community after Chinese Antarctic Expedition finally reached there in 2005, and with the ongoing International Polar Year （IPY） during August 2007. In this paper two data processing methods are used together to generate two 100-m cell size digital elevation models （DEMs） of the Dome A region （Dome A-DEM） by using Cokriging method to interpolate the ICESat GLAS data, with Ihde-DEM as a constraint. It provides fundamental data to glaciological and geophysical investigation in this area. The Dome A-DEM was applied to determining the ice-sheet surface elevations and coordinates of the south and north summits, defining boundaries of basins and ice ftowlines, deducing subglacial topography, and mapping surface slope and aspect in Dome A region. The DEM shows there are two （north and south） summits in Dome A region. The coordinate and the surface elevation of the highest point （the north summit） are 80°21＇29.86＂S, 77°21＇50.29＂E and 4092.71±1.43m, respectively. The ice thickness and sub-ice bedrock elevation at north summit are 2420m and 1672m, respectively. Dome A region contains four drainage basins that meet together near the south summit. Ice ftowlines, slope and aspect in detail are also derived using the DEM.
文摘The Amery Ice Shelf is the largest ice shelf in East Antarctica. A new DEM was generated for this ice shelf, using kriging to interpolate the data from ICE- Sat altimetry and the AIS-DEM. The ice thickness distribution map is converted from the new DEM, assuming hydrostatic equilibrium. The Amery Ice Shelf marine ice, up to 230 m thick, is concentrated in the northwest of the ice shelf. The volume of the marine ice is 2.38 × 10^3 km^3 and accounts for about 5.6% of the shelf volume.
