李晓莉,刘永柱. 2019. GRAPES全球奇异向量技术改进及试验分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.020
GRAPES全球奇异向量技术改进及试验分析
The improvement of GRAPES global extratropical singular vectors and experimental research
投稿时间:2018-03-16  修订日期:2018-07-16
DOI:10.11676/qxxb2019.020
中文关键词:  奇异向量,线性化边界层方案,GRAPES全球切线性模式
英文关键词:Singular vectors, Linearized planetary boundary layer parameterization, GRAPES model, Tangent linear model
基金项目:
作者单位E-mail
李晓莉 中国气象局数值预报中心 lixl@cma.gov.cn 
刘永柱 中国气象局数值预报中心 liuyzh@cma.gov.cn 
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中文摘要:
      基于总能量模的奇异向量扰动常用于构造集合预报的初始条件。以建立GRAPES全球集合预报系统为目的,基于前期研发的GRAPES全球模式奇异向量方法,本文在GRAPES全球切线性模式和伴随模式2.0版的框架下,开展了引入线性化边界层方案来改善奇异向量结构,并提高奇异向量计算效率的研究。通过连续试验,从奇异向量的扰动能量结构,扰动能量谱及扰动空间分布等方面,综合分析改进GRAPES全球奇异向量的结构及演变特征。试验结果表明,改进后的GRAPES奇异向量方法有效抑制了之前扰动能量在近地面层不合理的快速增长,同时,奇异向量最优扰动的结构更客观地体现了中高纬度区域大气初始条件中的斜压不稳定扰动及其演变,如在初始时刻奇异向量扰动能量主要位于对流层中层,并呈现出随高度向西倾向的大气斜压特征;经过线性化演变,扰动能量向较大水平尺度转移,并在垂直结构上表现出向对流层高层上传,及向对流层低层下传的特征等。针对GRAPES奇异向量迭代求解中伴随模式计算耗时为主的情况,改进伴随模式中GCR调用方式,并采用大内存存储法来提高其计算效率,进而将奇异向量总计算时间缩短了25%。总之,改进后的GRAPES奇异向量方法,可应用于构建面向业务应用的GRAPES全球集合预报系统。
英文摘要:
      The singular vectors (SVs) based on total-energy norm have been used generally for representing the initial uncertainty in the ensemble forecasting. The GRAEPE SVs based on the total-energy norm using the GRAPES dynamical core model was developed. The impacts and importance of linearized physical processes on the SVs have been widely studied in the literatures. To improve the GRAPES SVs, in this study based on the recently developed GRAPES tangent linear model (TLM) and ajoint model (ADM) version 2.0, the implementation of linearized planetary boundary layer (PBL) parameterization on the calculation of extratropical SVs is conducted. The characteristics of SVs and their linear evolution are measured by energy partition, energy spectra and spatial distribution through one–month experiments. The unreasonable quick energy growth near surface that was observed in the structure of SVs without linearized physical has been greatly improved, furthermore, the structures of upgraded SVs are more consistent with those of previous studies , showing the characteristics of typical total-energy based SVs: the energy maximum is located in the middle troposphere, with obvious westward tilt with height in the spatial structure of SVs at initial time; during their growth, there are upward energy transfer to upper troposphere and downward energy transfer to surface, and an upscale energy transfer is shown in the energy spectra. The results show the upgraded SVs are capable to capture the baroclinic instability in the troposphere. In order to improve the computation efficiency of GRAPES SVs, the ADM that is most time consuming is optimized by reducing the use of GCR (Generalized Conjugate-Residual) in the ADM and increasing computational memory, which decrease the total computation time of GRAPES SVs up to 25%. Therefore, the upgraded GRAPES SVs is satisfactory to meet the expectation for constructing the initial perturbation for GRAPES global ensemble prediction.
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