From the onset of melt in early June, corresponding declines in Ice, Cloud, and Land Elevation Satellite‐2 (ICESat‐2) freeboard and surface albedo can be seen over the entire Arctic sea ice cover. In the 2019 summer, area‐averaged freeboard decreased from 34 cm prior to melt to a minimum of 12 cm in August while the area‐averaged albedo decreased from ~0.7 to 0.38 for the same period. Calculations using ICESat‐2 freeboards and modeled ice thickness from Pan‐Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) give area‐averaged snow depths ranging from 17 cm prior to melt to 3 cm in August over seasonal ice and from 34 to 4 cm over multiyear ice. Mean rates of snow ablation (including evaporation) in mid‐June were as high as 2 cm/day, comparable to field records from other years. Increases in freeboard after mid‐August in the high latitude (>80°N) multiyear ice cover, north of the Greenland coast, are likely due to earlier freeze‐up and snow accumulation in these regions with shorter melt seasons.

中文翻译：

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2019年夏季融化期间ICESat-2收购中北极海冰积雪的衰减

从6月初融化开始，整个北极海冰覆盖范围内都可以看到冰，云和高空卫星2（ICESat-2）的干舷和地表反照率相应下降。在2019年夏季，平均面积干高从融化前的34厘米下降到8月的最低12厘米，而同期平均面积反照率从〜0.7降至0.38。使用ICESat-2干舷和来自泛北极冰洋建模和同化系统（PIOMAS）的模拟冰层厚度进行的计算得出，平均冰雪深度范围从融化前的17厘米到季节性冰上8月的3厘米，以及从34到4厘米多年的冰。6月中旬的平均融雪速度（包括蒸发）高达2厘米/天，与其他年份的实地记录相当。