北极多源积雪深度数据对比评估及其对海冰厚度估算的影响

Comparison and evaluation of multi-source Arctic snow depth data and its impact on the estimation of sea ice thickness

积雪深度是估算海冰厚度重要的参数之一,目前对不同积雪深度产品精度及其可适用范围的评估研究较少,也缺乏系统性的认知。本研究选取了11种北极积雪深度产品,根据产品的不同时间范围,分为2013—2018年和2018—2019年2个评估时间段。根据上述时间段,对比分析了各产品之间的差异性,然后将这些产品与“冰桥行动”和海冰质量平衡浮标的现场观测结果进行了评估。所有产品都显示格陵兰岛和加拿大北极群岛的北部积雪深度较厚,而在东西伯利亚海、拉普捷夫海、喀拉海、巴伦支海沿线区域的积雪深度较薄,不过,部分产品在时空变化上仍存在较大差异。与“冰桥行动”的观测数据对比发现,大部分产品数据雪深都较厚,AMSR2B和IS2/CS2分别在2013—2018年和2018—2019年的评估时间段内差异较小,拟合度较好。与海冰质量平衡浮标的对比结果显示,绝大部分产品数据雪深都较薄,并且差异性较大,其中NESOSIM在整个时期拟合度较好。利用不同产品的积雪深度反演海冰厚度的结果差异显著,与“冰桥行动”观测的海冰厚度对比发现,FY3B/MWRI和IS2/CS2分别在2013—2018年和2018—2019年的评估时间段内有着最好的拟合性。综合雪深和海冰厚度的验证结果来看,经验被动微波遥感、卫星测高以及组合类型的AMSR/AVHRR有着较好的拟合度,而雪深再分析模型产品的精度仍然需要进一步提升。

Snow depth is one of the important parameters for estimating sea ice thickness.However,there are few studies on the accuracy of different snow depth products and their applicable range,and there is also a lack of systematic cognition.In this study,eleven kinds of Arctic snow depth products are selected and divided into two evaluation periods,2013–2018 and 2018–2019,according to different time ranges of the products.Based on this time period,the differences between the products were compared and evaluated against the in-situ observational data of“Operation IceBridge”and sea ice mass balance buoys.All products show that the snow depth is thicker in the north of Greenland and the Canadian Arctic Archipelago,and thinner along the East Siberian Sea,Laptev Sea,Kara Sea and Barents Sea.However,there are still larger differences in temporal and spatial changes of some products.Compared with the observational data of“Operation Ice-Bridge”,most of the products are thicker.AMSR2B and IS2/CS2 have smaller difference and match better in the periods of 2013–2018 and 2018–2019 respectively.Compared with the observational data of sea ice mass balance buoys,most of the products are thinner and have larger differences.NESOSIM has a better fitting degree in the whole period.The retrieved results of sea ice thickness using snow depth of different products are significantly different.Compared with the observational data of“Operation IceBridge”,FY3B/MWRI and IS2/CS2 have the best fitting in the periods of 2013–2018 and 2018–2019,respectively.Based on the validation results of snow depth and sea ice thickness,empirical passive microwave remote sensing,satellite altimetry and combined AMSR/AVHRR have a better fitting degree,and the accuracy of snow depth reanalysis model products still needs to be further improved.