Multi temporal and spatial difference analysis of various MSS models and Arctic sea ice freeboard
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摘要: 基于2017年4月、2018年4月和2019年4月的CryoSat-2 L1B数据,比较分析了UCL13、DTU10、DTU13、DTU15和DTU18 5种不同平均海表面高度(MSS)模型及其反演的北极海冰干舷的多时空尺度差异。以UCL13为基准,对比分析不同MSS模型的差异和所反演的海冰干舷的差异,实验结果表明,不同MSS模型之间的平均绝对偏差范围为0.19~0.26 m,标准差范围为0.55~0.57 m,其中DTU18与UCL13的差异最小。以UCL13为基准,其他4种MSS模型反演的海冰干舷的平均绝对偏差为0.50~0.79 cm,标准差范围为1.17~1.74 cm。通过与冰桥计划(Operation IceBridge,OIB)机载数据相比,5种MSS模型反演的海冰干舷的相关系数范围为0.70~0.71,均方根误差范围为7.7~7.8 cm。故不同MSS模型之间的偏差对整个北极地区的海冰干舷反演的影响较小,偏差以相同的方式影响冰间水道和浮冰高度测量,因此相互抵消,但在冰间水道分布稀疏的区域,如加拿大群岛北部和拉普捷夫海区域,不同MSS模型反演的海冰干舷差异较大。Abstract: Based on the CryoSat-2 L1B data for April 2017−2019, this study compares and analyzes the multi temporal and spatial scale differences of UCL13, DTU10, DTU13, DTU15 and DTU18 mean sea surface height (MSS) models and the Arctic sea ice freeboard retrieval. The differences of various mean sea surface height models and the sea ice freeboard retrieval are compared with UCL13. The experimental results show that the average absolute deviation range between different MSS models is 0.19−0.26 m as well as the standard deviation range is 0.55−0.57 m, among which the difference between DTU18 and UCL13 is the smallest. The mean absolute deviation range of sea ice freeboard retrieved by the other four MSS models is 0.50−0.79 cm with the standard deviation range is 1.17−1.74 cm. Compared to airborne Operation IceBridge (OIB) data, the correlation coefficients of sea ice freeboard retrieved by the five MSS models range from 0.70 to 0.71 with the root mean square error range is 7.7−7.8 cm. Therefore, the biases between various MSS models have little influence on sea ice freeboard retrievals in the entire Arctic region, since biases impact both the lead and ice floe height measurements in the same way, and thus cancel out. However, in the areas with sparse leads, such as the northern Canadian Islands and the Laptev Sea, the sea ice freeboard retrieved by different MSS models varies greatly.
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Key words:
- mean sea surface height /
- CryoSat-2 /
- Arctic /
- sea ice freeboard /
- differential analysis
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图 9 UCL13和DTU系列MSS模型的北极海冰干舷网格差异
a, e, i. UCL13-DTU10;b, f, j. UCL13-DTU13;c, g, k. UCL13-DTU15;d, h, l. UCL13-DTU18;a–d. 2019年4月;e–h. 2018年4月;i–l. 2017年4月
Fig. 9 Grid differences of Arctic sea ice freeboard between UCL13 and series of DTU MSS models
a, e, i. UCL13-DTU10; b, f, j. UCL13-DTU13; c, g, k. UCL13-DTU15; d, h, l. UCL13-DTU18. a–d. April 2019; e–h. April 2018; i–l. April 2017
表 1 UCL13和DTU系列MSS模型的北极海冰干舷网格差异统计表
Tab. 1 Grid differences statistics of Arctic sea ice freeboard between UCL13 and series of DTU MSS models
对比网络 平均绝对偏差/标准差(单位:m) 2017年4月 2018年4月 2019年4月 UCL13−DTU10 0.006 9/0.017 4 0.007 0/0.014 9 0.007 9/0.016 8 UCL13−DTU13 0.006 4/0.017 3 0.006 3/0.014 0 0.007 2/0.015 8 UCL13−DTU15 0.005 4/0.015 8 0.005 2/0.012 7 0.005 7/0.013 7 UCL13−DTU18 0.005 2/0.014 5 0.005 0/0.011 7 0.005 5/0.012 8 -
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