| BI Haibo,HUANG Haijun,SU Qiao,YAN Liwen,LIU Yanxia,XU Xiuli. 2014. An Arctic sea ice thickness variability revealed from satellite altimetric measurements. Acta Oceanologica Sinica, 33(11):134－140 |
| An Arctic sea ice thickness variability revealed from satellite altimetric measurements |
| 基于卫星高度计的北极海冰厚度变化研究 |
| Received:January 22, 2014 Revised:March 20, 2014 |
| DOI：10.1007/s13131-014-0562-y |
| Key words:satellite altimetry ice thickness Arctic first-year ice multiyear ice |
| 中文关键词: 卫星高度计 海冰厚度 北极 一年冰 多年冰 |
| 基金项目: |
| Author Name | Affiliation | E-mail | | BI Haibo | Key laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China | | | HUANG Haijun | Key laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China | hjhuang@qdio.ac.cn | | SU Qiao | The First Institute of Oceanology, State Oceanic Administration, Qingdao 266061, China | | | YAN Liwen | Key laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China | | | LIU Yanxia | Key laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China | | | XU Xiuli | The First Institute of Oceanology, State Oceanic Administration, Qingdao 266061, China | |
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| Abstract: |
| A modified algorithm taking into account the first year (FY) and multiyear (MY) ice densities is used to derive a sea ice thickness from freeboard measurements acquired by satellite altimetry ICESat (2003-2008). Estimates agree with various independent in situ measurements within 0.21 m. Both the fall and winter campaigns see a dramatic extent retreat of thicker MY ice that survives at least one summer melting season. There were strong seasonal and interannual variabilities with regard to the mean thickness. Seasonal increases of 0.53 m for FY the ice and 0.29 m for the MY ice between the autumn and the winter ICESat campaigns, roughly 4-5 month separation, were found. Interannually, the significant MY ice thickness declines over the consecutive four ICESat winter campaigns (2005-2008) leads to a pronounced thickness drop of 0.8 m in MY sea ice zones. No clear trend was identified from the averaged thickness of thinner, FY ice that emerges in autumn and winter and melts in summer. Uncertainty estimates for our calculated thickness, caused by the standard deviations of multiple input parameters including freeboard, ice density, snow density, snow depth, show large errors more than 0.5 m in thicker MY ice zones and relatively small standard deviations under 0.5 m elsewhere. Moreover, a sensitivity analysis is implemented to determine the separate impact on the thickness estimate in the dependence of an individual input variable as mentioned above. The results show systematic bias of the estimated ice thickness appears to be mainly caused by the variations of freeboard as well as the ice density whereas the snow density and depth brings about relatively insignificant errors. |
| 中文摘要: |
| 本研究基于2003-2008年卫星高度计秋季和冬季的观测数据(ICESat), 对北极地区海冰厚度进行反演。本文使用的海冰厚度反演算法考虑了一年冰和多年冰密度的差异, 反演结果与地面实测数据基本保持一致, 两者偏差小于0.21m。ICESat数据反演的海冰厚度显示北极地区海冰存在明显的季节和年际变化。ICESat卫星秋季和冬季观测数据表明, 近4个月的时间间隔内一年冰和多年冰分别增加(0.53m)和(0.29m)。就年际变化而言, ICESat卫星数据证实多年冰厚度在2005-2008冬季观测时段出现明显减小趋势, 4年内减小幅度达到(0.8m), 而一年冰未出现明显的下降趋势。此外, 本文对所用的海冰厚度算法进行了误差评估, 结果表明海冰出水高度、海冰密度和雪厚度三种输入参量在多年冰区域能够引起高于0.5m的误差, 而在其它海冰区域的误差则小于0.5m。参量敏感度分析实验显示海冰出水高度和冰密度是引起海冰厚度反演偏差的主要因素, 相对而言, 雪厚度和雪密度参量引起的偏差较小。 |
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