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星载激光测高系统亚毫弧量级的发散角和冰层表面几乎没有穿透效应的优势使其非常适于监测南北极冰盖变化。利用GLAS激光测高卫星的高程数据,通过交叉和重复点方法分析2003~2009年3月格陵兰2 000 m以上区域冰盖高程变化,并改进了交叉点计算方法,使其适合纬度跨度较大的格陵兰地区。经过粗差剔除和时序解算,研究结果表明,该区域7年间冰盖高程年均变化+3.80 cm/年,中误差0.91 cm,呈缓慢增长趋势;交叉点和重复点方法所得结果趋势一致,重复点数量为交叉点数量的4~15倍,但位置分布不均匀,使用星载激光测高数据分析极地冰盖变化时,较大区域适合使用交叉点方法,较小区域适合使用重复点方法。
The sub-millimeter arc divergence angle of the sub-millimeter-arc laser altimetry system and the almost no penetration effect on the surface of the ice make it well suited for monitoring changes in ice sheeting in the South and North Pole. Based on the elevation data of satellite with GLAS laser, the elevation of ice cover in the area above 2,000 m in Greenland from March 2003 to March 2009 was analyzed by cross and repeated points method, and the calculation method of intersection was improved to make it fit for the large latitude span Greenland. After roughing elimination and timing solution, the results show that the average annual variation of ice cover elevation in this area is +3.80 cm / year with a median error of 0.91 cm, showing a slow growth trend; the results obtained by the method of intersection and repeated points are consistent, The number of repeat points is 4 ~ 15 times of the number of crossover points, but the location distribution is not uniform. When using the satellite laser altimeter data to analyze the changes of polar ice sheets, the larger area is suitable for the cross point method and the smaller area is suitable for the repeated point method .