Assimilation of sea ice motion in a finite‐element sea ice model
Assimilation of sea ice motion in a finite‐element sea ice model
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DOI：
10.1029/2008jc005067
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发表时间：
2009-05
影响因子：
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通讯作者：
K. Rollenhagen;R. Timmermann;T. Janjić;J. Schröter;S. Danilov
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文献类型：
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作者：
K. Rollenhagen;R. Timmermann;T. Janjić;J. Schröter;S. Danilov
[1]将有限元海冰模式（FESIM）应用于奇异进化内插卡尔曼（SEIK）滤波的资料同化研究。该模型已被配置为一个区域北极域，被迫与每日NCEP再分析数据的2米的空气温度和10米的风与月平均湿度从ECMWF再分析和气候场的降水和云量的组合。我们同化3天的平均冰漂流场来自被动微波卫星数据。基于多元协方差（描述不同模式场异常之间的统计关系），海冰漂移数据同化不仅产生直接的冰漂移修正，而且还更新海冰浓度和厚度，这反过来又产生可持续的冰漂移修正。我们使用观测浮标轨迹作为一个独立的数据集，以验证分析海冰漂移场。在参考模拟中已经实现了建模和观测轨迹之间的良好一致性。应用卫星衍生的漂移场的SEIK滤波器进一步提高了协议。冰厚度的空间和时间的变化增加，由于同化程序，从潜艇上看声纳的厚度数据的比较表明，厚度分布变得更加现实。卫星数据的验证表明，速度数据同化对冰浓度的影响很小，但冰浓度的总体改善仍然是显而易见的。
[1] A finite-element sea ice model (FESIM) is applied in a data assimilation study with the singular evolutive interpolated Kalman (SEIK) filter. The model has been configured for a regional Arctic domain and is forced with a combination of daily NCEP reanalysis data for 2-m air temperature and 10-m winds with monthly mean humidities from the ECMWF reanalysis and climatological fields for precipitation and cloudiness. We assimilate 3-day mean ice drift fields derived from passive microwave satellite data. Based on multivariate covariances (which describe the statistical relationship between anomalies in different model fields), the sea ice drift data assimilation produces not only direct modifications of the ice drift but also updates for sea ice concentration and thickness, which in turn yield sustainable corrections of ice drift. We use observed buoy trajectories as an independent data set to validate the analyzed sea ice drift field. A good agreement between modeled and observed tracks is achieved already in the reference simulation. Application of the SEIK filter with satellite-derived drift fields further improves the agreement. Spatial and temporal variability of ice thickness increases due to the assimilation procedure; a comparison to thickness data from a submarine-based upward looking sonar indicates that the thickness distribution becomes more realistic. Validation with regard to satellite data shows that the velocity data assimilation has only a small effect on ice concentration, but a general improvement of the ice concentration within the pack is still evident.