基于集合的观测资料影响性评价——简单AGCM的理想试验

Ensemble-Based Estimation of Observation Impact-Simplified AGCM Perfect Experiments

在Liu and Kalnay（2008）的研究基础上,将基于集合的观测资料影响性评价方法（简称LK08法）运用到一个简单的大气环流模式中,对模拟探空资料的预报影响性进行了综合评价,考察了LK08法在真实大气环流模式上的适用性。研究结果表明,应用基于集合的评价方法可以一次性计算出同化系统中每个观测的影响性,然后按观测手段、观测区域等进行影响性数值的简单累加,以此可以比较不同类型观测的相对影响性。比较结果显示,不同半球的模拟探空观测对预报的总影响性相差不大,但由于南半球资料个数要远远少于北半球,因此,南半球单个观测的影响性要大于北半球的单个观测。不同观测类型对预报的总影响性也不相同。有效性验证分析表明,按LK08法计算得到的总体观测影响性能解释实际影响性的70%~80%,且很好地抓住了其变化和走势。

Experiments of assessing observation impact with a simplified parameterization AGCM model are carried out to examine how the ensemble-based estimation method proposed by Liu and Kalnay（2008）（LK08）can be applied to the state-of-art models.The results show that LK08 can successfully estimate each observation＇s impact at once and then the impact values can be simply summed and grouped according to various types of observations or different areas.Although the summed observation impacts for the two hemispheres are similar,the individual observation impact in the Southern Hemisphere is much larger than that in the Northern Hemisphere due to the sparse observations there.The impacts for different observational types are also different.The estimated total observation impact accounts for 70%-80% of the actual impact and captures the variations of actual impact very well.