Fusion processing of multisource remote sensing images for extracting characteristic information from the Geladandong Snow Mountain area

Abstract

Objective In July 2022(Beijing time), the glacier survey group and mountaineering group of the China University of Geosciences (Wuhan) performed the "Second University Students' Scientific Expedition to the Yangtze River" in the Geladandong Snow Mountain area. Methods To analyse the spatial and temporal characteristics of glaciers in this region, scientific research data were combined with optical remote sensing image interpretation, InSAR deformation information extraction, LiDAR altimetry measurements, and high-precision geodetic survey data to conduct multisource remote sensing image fusion processing research. Aerial triangulation encryption, frequency domain image matching, the waveband ratio method, and visual interpretation were used to extract DOM, DSM, glacier area and number distribution information from high-resolution satellite GF1, GF6, GF7, ZY3, and Landsat 7 remote sensing images of Geladandong Snow Mountain and typical glaciers.Sentinel-1A and ICESat-2 images were used, supported by the cross-correlation offset tracking method in the SAR image space domain, to extract glacier surface velocity and elevation changes, respectively. The 3D spatial coordinates and elevation outliers of all the control points were calculated for the BDS CORS station in Qinghai Province using the Gamit/Globk double difference ionospheric combination model, real-time extended (RTX), and real-time kinematic (RTK) techniques. Results The results revealed 512 glaciers in the Geladandong Snow Mountain area, with an average annual growth rate of 3.12%, an area of 1 111.96 km2, and an average annual retreat rate of 0.63%.The average daily maximum velocity of the Jianggen (gu) Diru glacier is 0.25 cm/d, and the average annual maximum velocity is 91.25 cm/a. The maximum retreat value, accumulation value and annual change rate of Jianggen (gu) Diru glacier on the south side and north side are -74.63 m, 38.44 m, -5.29 m/a to 3.09 m/a, -39.17 m, 35.74 m, -3.02 m/a to 2.85 m/a, respectively. The precision of the regional quasigeoid refinement model and the errors at all control sites both attained mm levels. Conclusion The aforementioned findings can provide data support for subsequent research on glaciers in this region.

Keywords

• optical remote sensing interpretation
• sar offset tracking
• lidar altimetry
• bds cors
• geladandong snow mountain