Nudging资料同化对北极海冰密集度预报的改进

发布时间：2018-09-11 11:10

【摘要】：北极夏季海冰的快速减少使得北极航道提前开通成为可能。为了给北极冰区船运活动提供及时可靠有效的海冰预报保障,急需提高海冰预报水平。本文基于麻省理工大学通用环流模式(MITgcm),使用牛顿松弛逼近(Nudging)资料同化方法将德国不莱梅大学的第二代先进微波辐射成像仪(AMSR2)海冰密集度资料同化到模式中,建立了北极海冰数值预报系统。设计试验对比3种不同Nudging系数计算方案的改进效果,结果表明选择合适参数后,不同方案均能显著改进海冰密集度初始场。通过设计有无Nudging同化的两组预报试验,结合卫星遥感海冰密集度及中国第五次北极科学考察期间"雪龙"船的走航海冰密集度观测数据,定量分析了Nudging同化方案对北极海冰密集度的24~120h预报结果的改进效果。结果表明,Nudging同化对120h内全北极海冰密集度的空间分布和移动单点目标的海冰密集度预报结果均有显著改善;但在海冰变化很小的情况下,Nudging同化试验的24~120h预报结果均劣于惯性预报结果,说明基于Nudging同化的数值预报系统还需进一步提高预报技巧。
[Abstract]:The rapid reduction of Arctic summer sea ice has made it possible to open the Arctic Channel ahead of schedule. In order to provide timely, reliable and effective sea ice forecasting support for Arctic ice transport activities, it is urgent to improve the sea ice forecast level. Based on the general circulation model (MITgcm),) of the Massachusetts Institute of Technology (MIT), the data assimilation of the second-generation advanced microwave radiation imager (AMSR2) from the University of Bremen, Germany, into the model is based on the Newton relaxation approximation (Nudging) data assimilation method. A numerical forecasting system for Arctic sea ice is established. The experimental results show that the initial field of sea ice concentration can be significantly improved by the selection of suitable parameters. By designing two sets of forecasting experiments with or without Nudging assimilation, combined with satellite remote sensing sea ice density and the observation data of sea ice density of Xuelong vessel during the fifth Arctic scientific expedition of China, The improved effect of Nudging assimilation scheme on the prediction results of Arctic sea ice concentration for 24 ~ 120h is analyzed quantitatively. The results show that Nudging assimilation can significantly improve the spatial distribution of sea ice concentration in the whole Arctic and the prediction results of sea ice concentration of moving single point targets within 120 hours. However, under the condition that the sea ice change is very small, the prediction results of 24 ~ 120h in the nudging assimilation experiment are inferior to those of inertial prediction, which indicates that the numerical prediction system based on Nudging assimilation needs to improve the forecasting technique further.
【作者单位】：中国海洋大学海洋与大气学院;国家海洋环境预报中心国家海洋局海洋灾害预报技术研究重点实验室;中国极地研究中心;
【基金】：国家极地考察专项(CHINARE-03-01) 国家自然科学基金(41376188,41206184,41406218) 海洋公益性行业科研专项(201205007)
【分类号】：P731.15

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