GrADS可以读取GRIB格式的再分析数据，如ERA5，CFSR，CRA40等。对于这些数据，借助grib2ctl/g2ctl程序，生成描述文件(*.ctl文件)，再通过gribmap命令，生成索引文件（*.idx文件）从而实现对数据的读取。对于一部分数据创建的CTL文件，其var字段的内容比较显式，通过名称就可以知道它描述的是什么变量，变量的维数是多少等；而对于另一些数据创建的CTL文件，创建的var变量字段名称就比较抽象，难以明白其代表那些含义。
CFSR pgbh ctl的vars字段
vars 95 no4LFTXsfc 0,1,0 0,7,193 ** surface Best (4 layer) Lifted Index [K] no5WAVA500mb 0,100,50000 0,3,197 ** 500 mb 5-Wave Geopotential Height Anomaly [gpm] no5WAVH500mb 0,100,50000 0,3,193 ** 500 mb 5-Wave Geopotential Height [gpm] ABSVprs 37,100 0,2,10 ** (1000 975 950 925 900.. 7 5 3 2 1) Absolute Vorticity [1/s] CAPEsfc 0,1,0 0,7,6 ** surface Convective Available Potential Energy [J/kg] CAPE180_0mb 0,108,18000,0 0,7,6 ** 180-0 mb above ground Convective Available Potential Energy [J/kg] CAPE90_0mb 0,108,9000,0 0,7,6 ** 90-0 mb above ground Convective Available Potential Energy [J/kg] CAPE255_0mb 0,108,25500,0 0,7,6 ** 255-0 mb above ground Convective Available Potential Energy [J/kg] CINsfc 0,1,0 0,7,7 ** surface Convective Inhibition [J/kg] CIN180_0mb 0,108,18000,0 0,7,7 ** 180-0 mb above ground Convective Inhibition [J/kg] CIN90_0mb 0,108,9000,0 0,7,7 ** 90-0 mb above ground Convective Inhibition [J/kg] CIN255_0mb 0,108,25500,0 0,7,7 ** 255-0 mb above ground Convective Inhibition [J/kg] CLMRprs 32,100 0,1,22 ** (1000 975 950 925 900.. 70 50 30 20 10) Cloud Mixing Ratio [kg/kg] CWATclm 0,200,0 0,6,6 ** entire atmosphere (considered as a single layer) Cloud Water [kg/m^2] DPT30_0mb 0,108,3000,0 0,0,6 ** 30-0 mb above ground Dew Point Temperature [K] GPA1000mb 0,100,100000 0,3,9 ** 1000 mb Geopotential Height Anomaly [gpm] GPA500mb 0,100,50000 0,3,9 ** 500 mb Geopotential Height Anomaly [gpm] HGTsfc 0,1,0 0,3,5 ** surface Geopotential Height [gpm] HGTprs 37,100 0,3,5 ** (1000 975 950 925 900.. 7 5 3 2 1) Geopotential Height [gpm] HGT2pv 0,109,2e-06 0,3,5 ** PV=2e-06 (Km^2/kg/s) surface Geopotential Height [gpm] HGTneg2pv 0,109,-2e-06 0,3,5 ** PV=-2e-06 (Km^2/kg/s) surface Geopotential Height [gpm] HGTtop0C 0,204,0 0,3,5 ** highest tropospheric freezing level Geopotential Height [gpm] HGT0C 0,4,0 0,3,5 ** 0C isotherm Geopotential Height [gpm] HGTmwl 0,6,0 0,3,5 ** max wind Geopotential Height [gpm] HGTtrop 0,7,0 0,3,5 ** tropopause Geopotential Height [gpm] HLCY3000_0m 0,103,3000,0 0,7,8 ** 3000-0 m above ground Storm Relative Helicity [m^2/s^2] HLCY1000_0m 0,103,1000,0 0,7,8 ** 1000-0 m above ground Storm Relative Helicity [m^2/s^2] LFTXsfc 0,1,0 0,7,192 ** surface Surface Lifted Index [K] O3MRprs 37,100 0,14,192 ** (1000 975 950 925 900.. 7 5 3 2 1) Ozone Mixing Ratio [kg/kg] PLI30_0mb 0,108,3000,0 0,7,0 ** 30-0 mb above ground Parcel Lifted Index (to 500 hPa) [K] POTsig995 0,104,0.995 0,0,2 ** 0.995 sigma level Potential Temperature [K] PRESsfc 0,1,0 0,3,0 ** surface Pressure [Pa] PRESmsl 0,101,0 0,3,0 ** mean sea level Pressure [Pa] PRES2pv 0,109,2e-06 0,3,0 ** PV=2e-06 (Km^2/kg/s) surface Pressure [Pa] PRESneg2pv 0,109,-2e-06 0,3,0 ** PV=-2e-06 (Km^2/kg/s) surface Pressure [Pa] PRESmwl 0,6,0 0,3,0 ** max wind Pressure [Pa] PREStrop 0,7,0 0,3,0 ** tropopause Pressure [Pa] PRMSLmsl 0,101,0 0,3,1 ** mean sea level Pressure Reduced to MSL [Pa] PWAT30_0mb 0,108,3000,0 0,1,3 ** 30-0 mb above ground Precipitable Water [kg/m^2] PWATclm 0,200,0 0,1,3 ** entire atmosphere (considered as a single layer) Precipitable Water [kg/m^2] RHprs 37,100 0,1,1 ** (1000 975 950 925 900.. 7 5 3 2 1) Relative Humidity [%] RHsg330_1000 0,104,0.33,1 0,1,1 ** 0.33-1 sigma layer Relative Humidity [%] RHsg440_1000 0,104,0.44,1 0,1,1 ** 0.44-1 sigma layer Relative Humidity [%] RHsg720_940 0,104,0.72,0.94 0,1,1 ** 0.72-0.94 sigma layer Relative Humidity [%] RHsg440_720 0,104,0.44,0.72 0,1,1 ** 0.44-0.72 sigma layer Relative Humidity [%] RHsig995 0,104,0.995 0,1,1 ** 0.995 sigma level Relative Humidity [%] RH30_0mb 0,108,3000,0 0,1,1 ** 30-0 mb above ground Relative Humidity [%] RHclm 0,200,0 0,1,1 ** entire atmosphere (considered as a single layer) Relative Humidity [%] RHtop0C 0,204,0 0,1,1 ** highest tropospheric freezing level Relative Humidity [%] RH0C 0,4,0 0,1,1 ** 0C isotherm Relative Humidity [%] SPFHprs 37,100 0,1,0 ** (1000 975 950 925 900.. 7 5 3 2 1) Specific Humidity [kg/kg] SPFH30_0mb 0,108,3000,0 0,1,0 ** 30-0 mb above ground Specific Humidity [kg/kg] STRMprs 37,100 0,2,4 ** (1000 975 950 925 900.. 7 5 3 2 1) Stream Function [m^2/s] TMPprs 37,100 0,0,0 ** (1000 975 950 925 900.. 7 5 3 2 1) Temperature [K] TMP_1829m 0,102,1829 0,0,0 ** 1829 m above mean sea level Temperature [K] TMP_2743m 0,102,2743 0,0,0 ** 2743 m above mean sea level Temperature [K] TMP_3658m 0,102,3658 0,0,0 ** 3658 m above mean sea level Temperature [K] TMP_4572m 0,102,4572 0,0,0 ** 4572 m above mean sea level Temperature [K] TMPsig995 0,104,0.995 0,0,0 ** 0.995 sigma level Temperature [K] TMP30_0mb 0,108,3000,0 0,0,0 ** 30-0 mb above ground Temperature [K] TMP2pv 0,109,2e-06 0,0,0 ** PV=2e-06 (Km^2/kg/s) surface Temperature [K] TMPneg2pv 0,109,-2e-06 0,0,0 ** PV=-2e-06 (Km^2/kg/s) surface Temperature [K] TMPmwl 0,6,0 0,0,0 ** max wind Temperature [K] TMPtrop 0,7,0 0,0,0 ** tropopause Temperature [K] TOZNEclm 0,200,0 0,14,0 ** entire atmosphere (considered as a single layer) Total Ozone [DU] UGRDprs 37,100 0,2,2 ** (1000 975 950 925 900.. 7 5 3 2 1) U-Component of Wind [m/s] UGRD_1829m 0,102,1829 0,2,2 ** 1829 m above mean sea level U-Component of Wind [m/s] UGRD_2743m 0,102,2743 0,2,2 ** 2743 m above mean sea level U-Component of Wind [m/s] UGRD_3658m 0,102,3658 0,2,2 ** 3658 m above mean sea level U-Component of Wind [m/s] UGRD_4572m 0,102,4572 0,2,2 ** 4572 m above mean sea level U-Component of Wind [m/s] UGRDsig995 0,104,0.995 0,2,2 ** 0.995 sigma level U-Component of Wind [m/s] UGRD30_0mb 0,108,3000,0 0,2,2 ** 30-0 mb above ground U-Component of Wind [m/s] UGRD2pv 0,109,2e-06 0,2,2 ** PV=2e-06 (Km^2/kg/s) surface U-Component of Wind [m/s] UGRDneg2pv 0,109,-2e-06 0,2,2 ** PV=-2e-06 (Km^2/kg/s) surface U-Component of Wind [m/s] UGRDmwl 0,6,0 0,2,2 ** max wind U-Component of Wind [m/s] UGRDtrop 0,7,0 0,2,2 ** tropopause U-Component of Wind [m/s] USTM6000_0m 0,103,6000,0 0,2,194 ** 6000-0 m above ground U-Component Storm Motion [m/s] VGRDprs 37,100 0,2,3 ** (1000 975 950 925 900.. 7 5 3 2 1) V-Component of Wind [m/s] VGRD_1829m 0,102,1829 0,2,3 ** 1829 m above mean sea level V-Component of Wind [m/s] VGRD_2743m 0,102,2743 0,2,3 ** 2743 m above mean sea level V-Component of Wind [m/s] VGRD_3658m 0,102,3658 0,2,3 ** 3658 m above mean sea level V-Component of Wind [m/s] VGRD_4572m 0,102,4572 0,2,3 ** 4572 m above mean sea level V-Component of Wind [m/s] VGRDsig995 0,104,0.995 0,2,3 ** 0.995 sigma level V-Component of Wind [m/s] VGRD30_0mb 0,108,3000,0 0,2,3 ** 30-0 mb above ground V-Component of Wind [m/s] VGRD2pv 0,109,2e-06 0,2,3 ** PV=2e-06 (Km^2/kg/s) surface V-Component of Wind [m/s] VGRDneg2pv 0,109,-2e-06 0,2,3 ** PV=-2e-06 (Km^2/kg/s) surface V-Component of Wind [m/s] VGRDmwl 0,6,0 0,2,3 ** max wind V-Component of Wind [m/s] VGRDtrop 0,7,0 0,2,3 ** tropopause V-Component of Wind [m/s] VPOTprs 37,100 0,2,5 ** (1000 975 950 925 900.. 7 5 3 2 1) Velocity Potential [m^2/s] VSTM6000_0m 0,103,6000,0 0,2,195 ** 6000-0 m above ground V-Component Storm Motion [m/s] VVELprs 37,100 0,2,8 ** (1000 975 950 925 900.. 7 5 3 2 1) Vertical Velocity (Pressure) [Pa/s] VVELsig995 0,104,0.995 0,2,8 ** 0.995 sigma level Vertical Velocity (Pressure) [Pa/s] VWSH2pv 0,109,2e-06 0,2,192 ** PV=2e-06 (Km^2/kg/s) surface Vertical Speed Shear [1/s] VWSHneg2pv 0,109,-2e-06 0,2,192 ** PV=-2e-06 (Km^2/kg/s) surface Vertical Speed Shear [1/s] VWSHtrop 0,7,0 0,2,192 ** tropopause Vertical Speed Shear [1/s] ENDVARS