设 大气环流概述 Review ■历史回顾 ■内容简介 观测资料 资料处理与分析 ·再分析资料 ■分析方法 授课教师：张洋3
大气环流概述 ! 历史回顾 ! 内容简介 ! 观测资料 ! 资料处理与分析 ! 再分析资料 ! 分析方法 授课教师：张洋 3 Review
&售 大气环流概述一资料处理与分析 Review 举例：从站点资料到格点资料(data assimilation) Data assimilation: process by which observations are incorporated into a computer model of a real system; In each analysis cycle,observations of the current(and possibly past) state of a system are combined with the results from a numerical weather prediction model (the forecast)to produce an ana/ysis,which is considered as 'the best'estimate of the current state of the system; Data assimilation tries to balance the uncertainty in the data and in the forecast. 授课教师：张洋4
⼤⽓环流概述－资料处理与分析 ! 举例: 从站点资料到格点资料 (data assimilation) 授课教师：张洋 4 • Data assimilation: • process by which observations are incorporated into a computer model of a real system; • In each analysis cycle, observations of the current (and possibly past) state of a system are combined with the results from a numerical weather prediction model (the forecast) to produce an analysis, which is considered as 'the best' estimate of the current state of the system; • Data assimilation tries to balance the uncertainty in the data and in the forecast. data assimilation Review
设雾 大气环流概述一资料处理与分析 Review data assimilation “froze”analysis technique technique always in development, e.g.using models with higher resolution,better parameterization reanalysis data ERA NCEP/NCAR 授课教师：张洋 5
⼤⽓环流概述－资料处理与分析 授课教师：张洋 5 data assimilation reanalysis data ERA NCEP/NCAR “froze” analysis technique technique always in development, e.g. using models with higher resolution, better parameterization Review
设 大气环流概述一再分析资料 Review< 再分析资料：ERA-40和NCEP/NCAR NCEP(National Centers for Environmental Prediction)/ NCAR(National Center for Atmospheric Research) ■Dataset Product: o 1948.01.01-present,global grids 4-times daily and monthly Horizontal:2.5 X 2.5 degree(Basic) o Vertical:17 pressure levels (Basic) Model for data assimilation:T62 with 28 levels Reference:Kalnay et al.,1996:The NCEP/NCAR 40-year reanalysis project,Bull.Amer.Meteor.Soc.,77,437-470 http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html 授课教师：张洋 6
⼤⽓环流概述－再分析资料 ! 再分析资料：ERA-40和NCEP/NCAR " NCEP(National Centers for Environmental Prediction)/ NCAR(National Center for Atmospheric Research) ! Dataset Product: " 1948.01.01-present, global grids " 4-times daily and monthly " Horizontal: 2.5 X 2.5 degree (Basic) " Vertical: 17 pressure levels (Basic) ! Model for data assimilation: T62 with 28 levels ! Reference: Kalnay et al.,1996: The NCEP/NCAR 40-year reanalysis project, Bull. Amer. Meteor. Soc., 77, 437-470. ! http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html 授课教师：张洋 6 Review
&鲁 大气环流概述一资料处理 Review NCEP/NCAR再分析资料 物理量及分类 A(strongly influenced by observed data,hence,in the most reliable class):geopotential height,T,u,v... ■ B(although there are observational data directly affecting the value of the variable,the mode/also has a strong influence): relative humidity,w(vertical velocity),lowest level u and v... C(no observations directly affecting the variable,so that it is derived solely from the model forced by the data assimilation):radiation fluxes,surface heat fluxes,cloud forcing, precipitation rate... ● D(fixed from climatological values and does NOT depend on mode/s):surface roughness,surface geopotential height... 授课教师：张洋7
⼤⽓环流概述－资料处理 ! NCEP/NCAR 再分析资料 " 物理量及分类 ! A (strongly influenced by observed data, hence, in the most reliable class): geopotential height, T, u, v... ! B (although there are observational data directly affecting the value of the variable, the model also has a strong influence): relative humidity, w(vertical velocity), lowest level u and v... ! C (no observations directly affecting the variable, so that it is derived solely from the model forced by the data assimilation): radiation fluxes, surface heat fluxes, cloud forcing, precipitation rate... ! D (fixed from climatological values and does NOT depend on models): surface roughness, surface geopotential height... 授课教师：张洋 7 Review