Changes in surface elevation and velocity of Parlung No.4 glacier in southeastern Tibetan Plateau: monitoring by UAV technology

High-precision glacier change data is helpful for quantitative analysis of ice amount change and glacier dynamic movement change. Glacier monitoring by unmanned aerial vehicle (UAV) technology has the advantages of wide coverage, flexible observation time and high precision to overcome defects associated with traditional methods. UAV with PPK (Post Processed Kinematic) measurement technology was used to replace traditional control point (GCP) method to obtain three-phase high-precision DOM, DSM and three-dimensional point cloud data of Parlung No.4 glacier in the southeastern Tibetan Plateau from 2017 to 2018. Glacier surface elevation change, spatial difference of surface velocity and glacier microtopography characteristics were investigated. The horizontal and vertical precision of UAV products were found to be 0.11 and 0.17 m respectively. The decrease value of surface elevation difference of Parlung No.4 glacier showed a spatial distribution rule that decreased with elevation, glacier ice body was found to have thinned by 4.06 m. The surface velocity of glacier was found to increase with elevation, with the central streamline part of glacier slightly faster than the two sides. The landform characteristics of glacier surface tended to be “smooth” with elevation from high to low. The present work provides useful experience for future larger scale studies.