Nudging资料同化对北极海冰密集度预报的改进  

Improving Arctic sea ice concentration forecasts with a Nudging data assimilation method

作　　者：赵杰臣[1,2] 杨清华[2] 李明[2] 李群[3] 李春花[2] 田忠翔[2] 张林[2] 

机构地区：[1]中国海洋大学海洋与大气学院,山东青岛266100 [2]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,北京100081 [3]中国极地研究中心,上海200136

出　　处：《海洋学报》2016年第5期70-82,共13页

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)

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。The rapid decrease of Arctic sea ice in summer makes shipping in the Arctic possible.The accurate sea ice forecasts are urgently required to well service the Arctic shipping activities.A numerical Arctic forecasting system was built based on MIT general circulation model（MITgcm）ice-ocean coupled model and the Nudging data assimilation method was applied into this model and assimilate the Advanced Microwave Scanning Radiometer 2（AMSR2）sea ice concentration data.Three different kinds of Nudging assimilation schemes were firstly accessed and the results showed that all three nudging schemes can largely improve the initial sea ice concentration fields.For comparison,two forecasting experiments with and without Nudging assimilation but with the same forcing were designed to evaluate the role of nudging data assimilation.By comparing with the assimilated satellite-derived data and the ship-based in situsea ice concentration observations,it was shown that the nudging assimilation significantly improved the 24-120 hsea ice concentration forecasts.The results showed that improvements occurred not only in the whole Arctic sea ice concentration forecasts,but also in the single point forecasts.The persistence forecasts performed better in 24-120 hforecast than Nudging experiments when sea ice chance little in August.

关 键 词：北极海冰 密集度预报 Nudging 资料同化 

分 类 号：P731.32[天文地球—海洋科学]