Abstract
Geodetic mass changes in the Svalbard glaciers Austre Lovénbreen and Pedersenbreen were studied via high-precision real-time kinematic (RTK)-global positioning system (GPS) measurements from 2013 to 2015. To evaluate the elevation changes of the two Svalbard glaciers, more than 10,000 GPS records for each glacier surface were collected every year from 2013 to 2015. The results of several widely used interpolation methods (i.e., inverse distance weighting (IDW), ordinary kriging (OK), universal kriging (UK), natural neighbor (NN), spline interpolation, and Topo to Raster (TTR) interpolation) were compared. Considering the smoothness and accuracy of the glacier surface, NN interpolation was selected as the most suitable interpolation method to generate a surface digital elevation model (DEM). In addition, we compared two procedures for calculating elevation changes: using DEMs generated from the direct interpolation of the RTK-GPS points and using the elevation bias of crossover points from the RTK-GPS tracks in different years. Then, the geodetic mass balances were calculated by converting the elevation changes to their water equivalents. Comparing the geodetic mass balances calculated with and without considering snow depth revealed that ignoring the effect of snow depth, which differs greatly over a short time interval, might lead to bias in mass balance investigation. In summary, there was a positive correlation between the geodetic mass balance and the corresponding elevation. The mass loss increased with decreasing elevation, and the mean annual gradients of the geodetic mass balance along the elevation of Austre Lovénbreen and Pedersenbreen in 2013–2015 were approximately 2.60‰ and 2.35‰, respectively. The gradients at the glacier snouts were three times larger than those over the whole glaciers. Additionally, some mass gain occurred in certain high-elevation regions. Compared with a 2019 DEM generated from unmanned aerial vehicle measurement, the glacier snout areas presented an accelerating thinning situation in 2015–2019.
Highlights
Glaciers are an important component of the cryosphere, playing an important role in global climate change, and are often considered to be essential climate indicators [1,2]
Taking the real-time kinematic (RTK)-global positioning system (GPS) data of Pedersenbreen measured in 2013 as an example, we compared the digital elevation model (DEM) generated by interpolation methods were examined—AiunsvtreersLeovdéinsbtarenecne weighting (IDW) with spatial resolutions of 0.2 m, 0.5 m, 1 m, 2 m, and 5 m
It is difficult to calculate the mass balance accurately by a simple linear simulation, as the elevation changes in the lateral zones of the glacier are smaller than the change in the glacier’s center [22], and the classic glaciological method may not consider potential subglacier mass changes
Summary
Glaciers are an important component of the cryosphere, playing an important role in global climate change, and are often considered to be essential climate indicators [1,2]. In light of rapid global climate change, glacier loss is a major contributor to increases in sea level; glacier mass balance has become an important subject of research [3,4]. Since the Chinese Arctic Yellow River Station was built in 2004, Chinese researchers have focused on Arctic glaciers, carrying out long-term studies on Austre Lovénbreen and Pedersenbreen in Svalbard [17]. Chinese researchers have investigated the volume of Austre Lovénbreen and Pedersenbreen [18] and estimated the mass loss of Pedersenbreen during the periods from 1936 to 1990 and from 1990 to 2009 [9]. The velocities of the two glaciers have been studied, and the latest research has discussed the fastest ice flow region of Austre Lovénbreen by combining modeling methods with in situ surveying methods [19]
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