GPS掩星一维弯曲角算子在四维变分资料同化系统中的实现方法研究  

Research on the implementation of GPS radio occultation one-dimensional bending angle operator in four-dimensional variational data assimilation system

作　　者：朱孟斌[1] 张卫民[1] 曹小群[1] 

机构地区：[1]国防科学技术大学计算机学院,长沙410073

出　　处：《物理学报》2013年第18期538-545,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:40775064;41105063);公益性行业(气象)科研专项基金(批准号:GYHY201006015;GYHY201206007)资助的课题~~

摘　　要：GPS无线电掩星资料的良好特性使其作为十分重要的观测资料在欧洲及美国数值天气预报中效果明显.本文设计了一维弯曲角算子在四维变分资料同化系统中的实现方法和质量控制策略.详细阐述了一维弯曲角正演算子及其切线性/伴随算子在全球四维变分资料同化系统中的实现步骤和过程,其中折射率计算中采用Rüeger的折射率最佳平均因子的三项表达式,计算出更加精确的折射率值.对2012年8月份的GPS无线电掩星资料进行了观测误差统计,引入了更加符合四维变分资料同化系统实际情况的一维弯曲角观测误差模型和质量控制策略.同时,对比了观测误差统计试验中同化GPS无线电掩星资料的模式背景场和未同化GPS无线电掩星资料的背景场的观测误差统计结果,发现同化GPS无线电掩星资料之后的观测误差统计结果在全球区域正作用十分明显,尤其是在中低纬度地区,高度在10 km以上的区域观测误差减小十分明显.GPS radio occultation data are implemented in the numerical weather prediction as a kind of very important observation data because of its excellent characteristics, which makes a remarkable positive effect in the system. In this article, we design an implement method and a quality control strategy of one-dimensional bending angle operator in four-dimensional variational data assimilation system, and we also describe the steps of implementing one-dimensional bending angle forward operator and its linear and adjoint operators in four-dimensional variational data assimilation system. The author chose Riieger＇s three term expression and its best aver- age coefficients are chosen to calculate refractivity values. In this article, we introduce an observation error model of one-dimensional bending angle operator through the statistics of GPS radio occultation observation data of August, 2012. A comparison of experiment of the analysis field between in the cases with and without GPS radio occultation data is made. It is concluded that GPS radio occulta- tion data plays a positive role in the global areas, especially in the low and middle latitude areas higher than 10 kin. This conclusion is the foundation of the following-up GPS radio occultation data assimilation verification experiments.

关 键 词：GPS无线电掩星 一维弯曲角算子 四维变分同化系统 质量控制 

分 类 号：P228.4[天文地球—大地测量学与测量工程]