The Application of Flux-Form Semi-Lagrangian Transport Scheme in a Spectral Atmosphere Model  

作　　者：王晓聪 刘屹岷 吴国雄 Shian-Jiann LIN 包庆 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]NOAA/Geophysical Fluid Dynamics Laboratory,Princeton University,Princeton,New Jersey

出　　处：《Advances in Atmospheric Sciences》2013年第1期89-100,共12页大气科学进展（英文版）

基　　金：supported by the Chinese Academy of Science Strategic Priority Research Program (Grant No. XDA05110303);"973" Program (Grant Nos. 2010CB950403,2012CB417203,and 2013CB955803);"863" Program(Grant No. 2010AA012305);the National Natural Science Foundation of China (Grant Nos. 40925015,40875034,and 41023002)

摘　　要：A flux-form semi-Lagrangian transport scheme （FFSL） was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with less dissipation and dispersion, in comparison with other conventional schemes, hnportantly, FFSL can automatically maintain the positive definition of the transported tracers, which was an underlying problem in the previous spectral composite method （SCM）. To comprehensively investigate the impact of FFSL on GCM results, we conducted sensitive experiments. Three main improvements resulted： first, rainfall simulation in both distribution and intensity was notably improved, which led to an improvement in precipitation frequency. Second, the dry bias in the lower troposphere was significantly reduced compared with SCM simulations. Third, according to the Taylor diagram, the FFSL scheme yields simulations that are superior to those using the SCM： a higher correlation between model output and observation data was achieved with the FFSL scheme, especially for humidity in lower troposphere. However, the moist bias in the middle and upper troposphere was more pronounced with the FFSL scheme. This bias led to an over-simulation of precipitable water in comparison with reanalysis data. Possible explanations, as well as solutions, are discussed herein.A flux-form semi-Lagrangian transport scheme （FFSL） was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with less dissipation and dispersion, in comparison with other conventional schemes, hnportantly, FFSL can automatically maintain the positive definition of the transported tracers, which was an underlying problem in the previous spectral composite method （SCM）. To comprehensively investigate the impact of FFSL on GCM results, we conducted sensitive experiments. Three main improvements resulted： first, rainfall simulation in both distribution and intensity was notably improved, which led to an improvement in precipitation frequency. Second, the dry bias in the lower troposphere was significantly reduced compared with SCM simulations. Third, according to the Taylor diagram, the FFSL scheme yields simulations that are superior to those using the SCM： a higher correlation between model output and observation data was achieved with the FFSL scheme, especially for humidity in lower troposphere. However, the moist bias in the middle and upper troposphere was more pronounced with the FFSL scheme. This bias led to an over-simulation of precipitable water in comparison with reanalysis data. Possible explanations, as well as solutions, are discussed herein.

关 键 词：advection precipitation spectral composite method flux-form semi-Lagrangian Spectral Atmospheric Model of the IAP/LASG （SAMIL） 

分 类 号：X831[环境科学与工程—环境工程]