The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the...The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the total circumference of the Antarctic continent. In this study, we used a time series of ENVISAT ASAR images from 2004-2012 and flow lines derived from surface velocity data to monitor the changes in 12 tributaries of the Amery Ice Shelf front. The results show that the Amery Ice Shelf has been expanding and that the rates of expansion differ across the shelf. The highest average annual rate of advance from 2004-2012 was 3.36 m＇d-1 and the lowest rate was 1.65 m.d-1. The rates in 2009 and 2010 were generally lower than those in other years. There was a low correlation between the rate of expansion and the atmospheric temperature recorded at a nearby research station, however the mechanism of the relationship was complex. This study shows that the expansion of the Amery Ice Shelf is slowing down, reflecting a changing trend in climate and ice conditions in East Antarctica.展开更多
针对基于Wishart分布马尔可夫场(Markov random field,MRF)海陆分割存在海面和陆地整体区域无法使用单一Wishart分布描述的问题,提出了一种基于混合Wishart分布的极化合成孔径雷达(synthetic aperture radar,SAR)图像海岸线检测方法。...针对基于Wishart分布马尔可夫场(Markov random field,MRF)海陆分割存在海面和陆地整体区域无法使用单一Wishart分布描述的问题,提出了一种基于混合Wishart分布的极化合成孔径雷达(synthetic aperture radar,SAR)图像海岸线检测方法。该方法首先对极化SAR总功率边缘能量采用两区域Ostu阈值分割得到初始海陆分割结果,然后采用混合Wishart分布描述陆地和海面区域,通过基于混合Wishart分布MRF两区域分割迭代计算实现海陆精确分割。最后对经过水域合并处理的海陆分割结果进行边界跟踪实现海岸线检测。分别使用了RADARSAT2中国海南陵水地区和新加坡部分地区极化SAR数据进行实验,实验结果证明提出方法比基于Wishart分布MRF分割方法更加精确和鲁棒。展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education (Grant no.20120003110030)the China Postdoctoral Science Foundation (Grant no.201104063)+1 种基金the Open Fund of the SOA Key Laboratory for Polar Science (Grant no.KP201101)the Fundamental Research Funds for the Central Universities (Grant no.105560GR)
文摘The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the total circumference of the Antarctic continent. In this study, we used a time series of ENVISAT ASAR images from 2004-2012 and flow lines derived from surface velocity data to monitor the changes in 12 tributaries of the Amery Ice Shelf front. The results show that the Amery Ice Shelf has been expanding and that the rates of expansion differ across the shelf. The highest average annual rate of advance from 2004-2012 was 3.36 m＇d-1 and the lowest rate was 1.65 m.d-1. The rates in 2009 and 2010 were generally lower than those in other years. There was a low correlation between the rate of expansion and the atmospheric temperature recorded at a nearby research station, however the mechanism of the relationship was complex. This study shows that the expansion of the Amery Ice Shelf is slowing down, reflecting a changing trend in climate and ice conditions in East Antarctica.
文摘针对基于Wishart分布马尔可夫场(Markov random field,MRF)海陆分割存在海面和陆地整体区域无法使用单一Wishart分布描述的问题,提出了一种基于混合Wishart分布的极化合成孔径雷达(synthetic aperture radar,SAR)图像海岸线检测方法。该方法首先对极化SAR总功率边缘能量采用两区域Ostu阈值分割得到初始海陆分割结果,然后采用混合Wishart分布描述陆地和海面区域,通过基于混合Wishart分布MRF两区域分割迭代计算实现海陆精确分割。最后对经过水域合并处理的海陆分割结果进行边界跟踪实现海岸线检测。分别使用了RADARSAT2中国海南陵水地区和新加坡部分地区极化SAR数据进行实验,实验结果证明提出方法比基于Wishart分布MRF分割方法更加精确和鲁棒。
