基于机载LiDAR的高寒山区遥感高程数据精度评估

Accuracy Evaluation of Remote Sensing Elevation Data in Alpine Mountains based on Airborne LiDAR

遥感高程数据是获取缺资料地区DEM(Digital elevation models)数据的重要手段。然而,由于高寒山区实地高程测量稀少,难以对多源遥感DEM数据进行统一验证。ICESat-2等新的遥感高程数据在高寒山区也缺乏相应的精度评估。针对此问题,以青藏高原东北缘的冰沟流域作为研究区,采用机载航空遥感获取的大范围LiDAR(Light Detection And Ranging)DEM数据对新产品ICESat-2 ATL06(Ice,Cloud,and Land Elevation Satellite-2,Land Ice Height)、ALOS DEM(12.5 m分辨率)以及新版本SRTM V3(SRTM Arc-Second Global 1 V003)、ASTER GDEM V3(ASTER Global DEM)进行验证,并分析地形因子与均方根误差RMSE的关系。研究结果表明:ICESat-2 ATL06数据在高寒山区的RMSE为0.747 m。由于其较高的精度,可用于验证缺资料地区的其他遥感高程数据。其他遥感高程数据的精度都相对较低,ALOS 12.5 m数据的RMSE为5.284 m;ASTER GDEM V3版本的RMSE为9.903 m。实验所采用的4种遥感高程数据与机载LiDAR DEM均具有较高的相关性,相关系数在0.998与1.000之间。实验还揭示了坡度是影响遥感DEM精度的主要因素。除ICESat-2 ATL06外,其他高程数据的RMSE均随坡度的增大先减小再增大,且都存在一个最佳坡度值。鉴于地形复杂多样的冰沟流域具有青藏高原高寒山区的典型特征,多源遥感DEM数据在该区域的验证结论具有较好的代表性,可为相似地区DEM数据的使用和评估提供重要的知识补充。

Remote sensing is an essential means to obtain DEM data in areas lacking information.However,due to the scarcity of field elevation measurements in alpine mountains,it is difficult to verify multi-source remote sensing DEM data uniformly.New remote sensing elevation data such as ICESAT-2 also lack the corresponding accuracy evaluation in alpine mountainous areas.To solve this problem,we take the Binggou Basin on the northeast margin of the Tibetan plateau as the research area.Applying the wide range of LiDAR DEM data acquired by airborne airborne remote sensing to the new product ICESAT-2 ATL06,ALOS DEM 12.5 m,the new version of SRTM V3 and ASTER GDEM were verified,and the relationship between terrain factor and RMSE was analyzed.The results show that ICESat-2 ATL06 can reach 0.747 m in RMSE in alpine mountains.Because of its high precision,it can be used to verify other remote sensing elevation in the data shortage area.The accuracy of other remote sensing elevation is relatively low.The RMSE of ALOS 12.5 m data is5.284 m.RMSE of ASTER GDEM V3 version is 9.903 m.The five kinds of remote sensing elevation data used in this study have a high correlation with airborne LiDAR DEM,with the correlation coefficient between0.997 and 1.000.Our study also reveals that slope is the main factor affecting the accuracy of remote sensing DEM.Except ICESat-2 ATL06,RMSE of other elevation data decreases first and then increases with the increase of slope,and there is an optimal slope value for all of them.In view of the typical characteristics of the alpine mountains on the Tibetan plateau,the verification conclusions of multi-source remote sensing DEM data in this region are representative,which can provide an important knowledge supplement for the application and evaluation of laser remote sensing DEM data in similar areas.