高原气象2025，Vol.44Issue(3)：657-671,15.DOI:10.7522/j.issn.1000-0534.2024.00098
基于对流尺度集合样本的高原边坡对流系统和台风系统多元变量背景场误差特征研究
Study of Multivariate Background Error Characteristics of Convective System on Plateau Slope and Typhoon System Based on Convective-Scale Ensemble Samples
摘要
Abstract
The effective assimilation of observation data in the slope areas of the Qinghai-Xizang(Tibetan)Pla-teau and typhoon systems has a significant impact on the capabilities of weather forecasting in China,with back-ground error being a key factor affecting the performance of data assimilation.The purpose of this study is to gain a deeper understanding of the characteristics of background errors in conventional control variables and hydrome-teor control variables within convective systems on the slopes of the Qinghai-Xizang(Tibetan)Plateau and ty-phoon systems,so as to develop the data assimilation scheme which is applicable to the convective systems on the slopes of the Qinghai-Xizang(Tibetan)Plateau and typhoon systems.This study employs the Ensemble Transform Kalman Filter(ETKF)and the hybrid Ensemble-Variational data assimilation method to update the ensemble perturbation and the ensemble mean respectively to produce convective-scale ensemble forecast sam-ples with 80 ensemble members and 4-kilometers resolution.This study focuses on cases of convective weather from the northeast slope of the Qinghai-Xizang(Tibetan)Plateau in mid-August 2022 and Typhoon"Meihua",the 12th typhoon of 2022.Multivariate background error covariances,including those for multiphase hydromete-or and vertical velocity,were computed through physical transformation,vertical transformation,and horizontal transformation.Analyses of the spatial error characteristics,including the eigenvalues,eigenvectors,and charac-teristic length scales were conducted,and the results of the analyses indicate that background errors are more pro-nounced in the case of convective system on the slope of the Qinghai-Xizang(Tibetan)Plateau in comparison to the typhoon system.At the same time,the simulation of hydrometeor variables and vertical velocity is less pre-cise in the case of convective system on the slope of the Qinghai-Xizang(Tibetan)Plateau compared to the ty-phoon system.In the context of data assimilation for these comparable convective systems,the analysis tends to be more aligned with observations and less so with the background,this feature highlights the necessity for high-quality and comprehensive observations in the slope areas of the Qinghai-Xizang(Tibetan)Plateau.In addition,the atmospheric characteristics and the horizontal scale of hydrometeor variables and vertical velocity in the case of convective system on the slope of the Qinghai-Xizang(Tibetan)Plateau display smaller and more localized features compared with those observed in the typhoon system.Moreover,hydrometeor control variables and the vertical velocity exhibit smaller horizontal scales and more pronounced localized characteristics compared to con-ventional control variables,therefore potentially leading to the influence range of observations and information related to hydrometeor control variables in the slope areas of the Qinghai-Xizang(Tibetan)Plateau relatively lim-ited in the context of the subsequent assimilation analysis.关键词
背景场误差/资料同化/高原边坡对流/台风Key words
background error/data assimilation/plateau slope convection/typhoon分类
天文与地球科学引用本文复制引用
张万里,王元兵,李柔,陈耀登,孟德明,钱新尧,金喜立..基于对流尺度集合样本的高原边坡对流系统和台风系统多元变量背景场误差特征研究[J].高原气象,2025,44(3):657-671,15.基金项目
国家自然科学基金项目(U2142208,42105149) （U2142208,42105149）
国家重点研发计划项目(2022YFC3080500) （2022YFC3080500）
