High-Resolution Monitoring of Glacier Mass Balance and Dynamics with Unmanned Aerial Vehicles on the Ningchan No. 1 Glacier in the Qilian Mountains, China

Abstract

Glaciers located in the Qilian Mountains are rapidly retreating and thinning due to climate change. The current understanding of small glacier mass balance changes under a changing climate is limited by the scarcity of in situ measurements in both time and space as well as the resolution of remote sensing products. Unmanned aerial vehicles (UAVs) provide an unparalleled opportunity to track the spatiotemporal variations in glacier extent at a high resolution and the changing glacier morphological features related to glacial dynamics. Five measurements were performed on the Ningchan No. 1 (NC01) glacier in the Qilian Mountains between 18 August 2017 and 13 August 2020. The glacier changes displayed in the digital orthophoto maps (DOMs) and digital surface models (DSMs) show a 7.4 ± 0.1 m a−1 retreat of the terminus of NC01, a mass balance of −1.22 ± 0.1 m w.e. a−1 from 2017 to 2020, and a maximum surface velocity of 3.2 ± 0.47 m from 18 August 2017 to 26 August 2018, which clearly show consistency with stake measurements. The surface elevation change was influenced by the combined effects of air temperature, altitude, slope, and surface velocity. This research demonstrates that UAV photogrammetry can greatly improve the temporal and spatial resolution of glaciological research.

Estimation of River Discharge Using Unmanned Aerial Vehicle (UAV) Based on Manning Formula for an Ungauged Alpine River in the Eastern Qilian Mountains

“…( 3) River information extraction: the segmented UAV image was imported into Pix4D software, and the complete river section image was derived through image mosaic, point cloud encryption, quality analysis, and other steps. The average errors in both vertical and horizontal directions measured by UAV were at the level of centimeters, which was accurate enough to meet the extraction of river topographic information [10].…”

“…In recent years, the development of unmanned aerial vehicle (UAV) aerial photogrammetry makes it convenient and reliable to obtain the terrain information of the underlying surface [10][11][12][13]. It has been widely used in monitoring dynamic changes in mountain glaciers [10][11][12][13][14], river morphology [15,16] and surface deformation [17], water quality [18], water turbidity [19], flood events [20], and changes in the coastal zone [21]. For river monitoring, many studies have been carried out using UAV data for river information gathering and discharge estimation [22] and river terraces and water erosion change monitoring [23].…”

UAV and GPR Data Integration in Glacier Geometry Reconstruction: A Case Study from Irenebreen, Svalbard

“…When individual glaciers are considered, also GNSS measurements of the glacier surface elevation [11] and LiDAR data [3,12,13] are used; however, the acquisition of LiDAR data can be time-consuming, logistically challenging, and requires expensive equipment with related transportation costs to the areas of high altitude. In the recent decade, an increase in glacier surface DEMs obtained via photogrammetric processing of aerial photographs obtained by UAVs can be observed [14][15][16][17][18][19][20][21][22].…”

Mid-Term Monitoring of Glacier’s Variations with UAVs: The Example of the Belvedere Glacier

“…The rising number of recent works [34][35][36] highlights the potential of UAVs and low-cost photogrammetry to efficiently monitor small and mid-scale glaciers with high spatial resolution. In fact, UAVs allows for extensively reconstruct glaciers morphology (e.g., with DSMs and orthophotos) with limited in-situ operations and costs [29].…”