Quantitative analysis of Arctic ice flow acceleration with increasing temperature

This study explores the ice flow acceleration(21.1%)of Pedersenbreen during 2016–2017 after the extremely warm winter throughout the whole Arctic in 2015/2016 using in situ data and quantitatively analyses the factors contributing to this acceleration.Several data sets,including 2008–2018 air temperature data from Ny-?lesund,ten-year in situ GPS measurements and Elmer/Ice ice flow modelling under different ice temperature scenarios,suggest that the following factors contributed to the ice flow acceleration:the softened glacier ice caused by an increase in the air temperature(1.5℃)contributed 2.7%–30.5%,while basal lubrication contributed 69.5%–97.3%.The enhanced basal sliding was mostly due to the increased surface meltwater penetrating to the bedrock under the rising air temperature conditions;consequently,the glacier ice flow acceleration was caused mainly by an increase in subglacial water.For Pedersenbreen,there was an approximately one-year time lag between the change in air temperature and the change in glacier ice flow velocity.

GPS-derived horizontal ice flow velocities along the traverse route from Zhongshan Station to Dome-A, East Antarctica

The traverse route from Zhongshan Station to Dome A is one of the most important expedition routes of ITASE Project. China carried out 3 inland traverses during the 1996/1997, 1997/1998, 1998/1999 austral summer field seasons. The field team reached inland 300 km, 500 km and 1100 km away from Zhongshan Station respectively. Some ice motion stakes were set up, occupied and reoccupied along the route by GPS technology. It showed that the ice along the traverse route flowed with an 8 25 ma -1 velocity to the northwest, the direction of the bottom of Lambert Glacier Basin. They coincide with the results along the eastern section from LGB59 70 of the LGB route deduced by Australia in both values and directions. Furthermore, the directions of the horizontal flow are perpendicular to the surface topography contour. The much larger velocity at the point of LT980 with an approximate value of 100 ma -1 was probed. It was caused by a 15 km wide trough on the bed beneath this point.

Surface mass balance and ice flow of the glaciers Austre Lovenbreen and Pedersenbreen,Svalbard,Arctic

The glaciers Austre Lovenbreen and Pedersenbreen are located at Ny-（？）lesund. Svalbard.The surface mass balance and ice flow velocity of both glaciers have been determined from the first year of observations（2005/2006）.while the front edge of Austre Lovenbreen was also surveyed.The results are as follows： （1） The net mass balances of Austre Lovenbreen and Pedersenbreen are—0.44 and—0.20 m w.e.,the annual ablation is—0.99 and—0.91 m w.e.. and the corresponding equilibrium line altitudes are 178.10 and 494.87 m.respectively. （2） Austre Lovenbreen and Pedersenbreen are characterized as ice flow models of surge-type glaciers in Svalbard.The horizontal vectors of the ice flow velocities are parallel or converge to the central lines of both glaciers,with lower velocities in the lower ablation areas and higher velocities in the middle and upper reaches of the glaciers.The vertical vectors of ice flow velocities show that there is a mass loss in the ablation areas,which reduces with increasing altitude, while there is a mass gain near the equilibrium line of Austre Lovenbreen.（3） The front edge of Austre Lovenbreen receded at an average rate of 21.83 m·a^（-1）,with remarkable variability-a maximum rate of 77.30 m·a^（-1） and a minimum rate of 2.76 m·a^（-1）.

The internal COF features in Dome A of Antarctica revealed by multi-polarization-plane RES

The ice exceeding one million years old has significant meaning for verifying and interpreting the middle Pleistocene transition （MPT） and the relationship between greenhouse gas and climate change. The region near Dome A in Antarctica satisfies the conditions for obtaining million-years-old ice since it has low temperatures and low accumulation rates. We analyze the corresponding relation between radar wave features and the crystal orientation fabric （COF） types based on the results of multi-polarization plane radio echo sounding （RES）. The results show that, even in the summit of the ice sheet, the COF type is not perfect, but is an elongated single-pole COF. Principal-axis-orientation differences of the COF among the different periods exist and reveal that the ice flow orientations are not constant but deviate clockwise with the increasing depth. This may be related to the adjacent basal valley or both height and position changes of the summit during the glacial-interglacial periods.

Antarctic Traverses from Zhongshan Station to Dome-A and the Result Analysis for the GPS Points along the Expedition Route

Some GPS points were set up and occupied and reoccupied along the traverse route from Zhongshan Station to DomeA.The result analysis for the GPS data processed by GAMIT/GLOBK package was presented in this paper.It was indicated that the ice along the traverse route flowed with an 825 m/a velocity to the northwest in the last three years,which was the direction of the edge of the ice sheet.The maximum horizontal flow velocity is about 100 m/a.Moreover,due to the ice flow,a 0.21 m/a sedimentation rate is achieved.Finally,a 15 m/a 2 horizontal acceleration is achieved from the GPS data of the three different stages.

Investigating the dynamics and interactions of surface features on Pine Island Glacier using remote sensing and deep learning

Pine Island Glacier(PIG),the largest glacier in the Amundsen Sea Embayment of West Antarctica,has contributed to over a quarter of the observed sea level rise around Antarctica.In recent years,multiple observations have confirmed its continuous retreat,ice flow acceleration and profound surface melt.Understanding these changes is crucial for accurately monitoring ice mass discharge and future Antarctic contributions to sea level rise.Therefore,it is essential to investigate the complex interactions between these variables to comprehend how they collectively affect the overall stability of the intricate PIG system.In this study,we utilized high-resolution remote sensing data and deep learning method to detect and analyze the spatio-temporal variations of surface melt,ice shelf calving,and ice flow velocity of the PIG from 2015 to 2023.We explored the correlations among these factors to understand their long-term impacts on the glacier's stability.Our findings reveal a retreat of 26.3 km and a mass loss of 1001.6 km^(2) during 2015-2023.Notably,extensive surface melting was observed,particularly in the 2016/2017 and 2019/2020 melting seasons.Satellite data vividly illustrate prolonged and intense melting periods,correlating with a significant retreat in the glacier's terminus position in 2019/2020.Furthermore,the comprehensive analysis of surface melting and the cumulative retreat of the ice shelf from 2017 to 2020 on the PIG shows atemporal relationship with subsequent significant changes in ice fow velocity,ranging from 10.9 to 12.2 m d^(-1),with an average acceleration rate of 12%.These empirical findings elucidate the intricate relationship among surface melt,ice flow velocity,and consequential glacier dynamics.A profound understanding of these interrelationships holds paramount importance in glacier dynamic changes and modeling,providing invaluable insights into potential glacier responses to global climate change.

Measurement of ice flow velocities from GPS positions logged by short-period seismographs in East Antarctica

The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in seismic imaging.