Surface elevation changes of Svalbard surge-type glaciers in 2019-2022 based on ICESat-2 altimetry
The Svalbard Archipelago is one of the most climate-sensitive areas in the world.Affected by the Arc-tic amplification effect,most of glaciers there have been undergoing significant shrinkage.Previous studies indi-cated that mass loss of glaciers in Svalbard accelerated in the past decades,but the ice mass loss caused by surge-type glaciers in the region remains unclear.Based on the high-precision observations from ICESat-2 laser altime-try,this study utilizes an improved classification method to investigate the elevation changes of the Svalbard's glacier during the period from March 2019 to June 2022.The results show that,from 2019 to 2022,the eleva-tion change of glaciers in the Svalbard shows a declining trend,with an average elevation change rate of(-0.94±0.23)m·a-1,corresponding to a volume change rate of(-31.62±7.73)km3·a-1.Among them,the surging gla-ciers occupy about 22％of the area,with a volume change rate of-13.23 km3·a-1,accounting for 42％of the to-tal volume change in the glacial area.Therefore,changes in surging glaciers are one of the main factors leading to the whole ice volume reduction in the region.As the largest surging glacier in the Svalbard,Storisstraumen Glacier has expanded its surge area by about 284 km2 in the past 20 years,with a volume change rate of-5.67 km3·a-1,accounting for 18％of the total ice volume loss in the area.Further analysis suggests that the increase in temperature may play a dominant role in triggering the surging of Storisstraumen glacier.This study not only re-veals the elevation change characteristics of glaciers in Svalbard during the span from 2019 to 2022,but also quantifies the contribution from surge-type glaciers to the total ice mass loss in Svalbard,which may provide a reference for deep understanding the varying elevation change of glaciers in the region.
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