Accuracy assessment of ICESat-2 ATL 08 terrain estimates:A case study in Spain

ICESat-2 ATL 08地形产品精度验证:以西班牙为例

The Ice,Cloud and Land Elevation Satellite-2(ICESat-2),a new spaceborne light detection and ranging(LiDAR)system,was successfully launched on September 15,2018.The ICESat-2 data increase the types of spaceborne LiDAR data archive and provide new control point data for large-scale topographic mapping and geodetic surveying.However,the accuracy of the ATL 08 terrain estimates has not been fully evaluated on a large scale and in complex terrain conditions.This article aims to quantitatively assess the accuracy of ICESat-2 ATL 08 terrain estimates.Firstly,the ICESat-2 ATL 08 terrain estimates were compared with the high-precision airborne LiDAR digital terrain model(DTM),and impacts of acquisition time,vegetation cover type,terrain slope,and season change on the terrain estimation accuracy were analyzed.We get the following conclusions from the analysis:1)the mean and RMSE of the terrain estimates of day acquisitions are 0.22 m and 0.59 m higher than that of night acquisitions;2)the accuracy of the ATL 08 terrain estimates acquired in vegetated areas is lower than those in non-vegetated areas;3)the accuracy of the ATL 08 terrain estimates is inversely proportional to the slope,and the elevation error increases significantly when the terrain slope is larger than 30°;4)in the non-vegetation covered area,the accuracy of the ATL 08 terrain estimates of summer and winter acquisitions has no obvious discrepancy,but in vegetated area,the accuracy of winter acquisitions is significantly better than that of summer acquisitions.This research provides references for the selection and application of ICESat-2 data.

新一代星载激光雷达(Ice,Cloud and Land Elevation Satellite-2;ICESat-2)于2018年9月15日成功发射。ICESat-2丰富了星载激光雷达数据种类,为大范围地形制图和大地测量提供了新的控制点数据。然而,ATL 08地形估计值的准确性尚未在大规模和复杂地形条件下进行全面评估。本文旨在大范围定量评估ICESat-2 ATL 08地形估计值的精度情况。将ICESat-2 ATL 08地形估计值与高精度机载LiDAR数字地形模型(DTM)进行比较,并分析了采集时间、植被覆盖类型、地形坡度和季节变化对地形估计精度的影响。通过分析得出以下结论:1)白天获取的地形产品数据的平均误差和均方根误差比夜间分别高0.22 m、0.59 m;2)有植被覆盖地区的ATL 08地形估计值精度要低于非植被覆盖地区;3)ATL 08地形估计值精度与坡度呈现反比关系,当坡度大于30°时,高程误差显著增大;4)夏季和冬季获取的ATL 08产品数据的精度在非植被区无明显差异,而在植被区冬季数据精度明显优于夏季数据。本文将为用户选取和应用ICESat-2产品数据提供有益指导。