(1) FNL 数据介绍
FNL(（Final Operational Global Analysis)数据是美国国家环境预报中心（NECP）/美国国家大气研究中心（NCAR）提供的全球再分析资料，空间精度为1°×1°，通过FNL数据可以了解真实的全球区域气象状况。（详见https://rda.ucar.edu/datasets/ds083.2/）。
fnl数据变量表：
| Discipline | Category | Code | Short Name | Description | Units |
|---|---|---|---|---|---|
| 0 | 0 | 0 | TMP | Temperature | K |
| 0 | 0 | 2 | POT | Potential temperature | K |
| 0 | 0 | 4 | T MAX | Maximum temperature | K |
| 0 | 0 | 5 | T MIN | Minimum temperature | K |
| 0 | 0 | 10 | LHTFL | Latent heat flux | W m-2 |
| 0 | 0 | 11 | SHTFL | Sensible heat flux | W m-2 |
| 0 | 1 | 0 | SPF H | Specific humidity | kg kg-1 |
| 0 | 1 | 1 | R H | Relative humidity | % |
| 0 | 1 | 3 | P WAT | Precipitable water | kg m-2 |
| 0 | 1 | 7 | PRATE | Precipitation rate | kg m-2 s-1 |
| 0 | 1 | 8 | A PCP | Total precipitation | kg m-2 |
| 0 | 1 | 10 | ACPCP | Convective precipitation | kg m-2 |
| 0 | 1 | 13 | WEASD | Water equivalent of accumulated snow depth | kg m-2 |
| 0 | 1 | 22 | CLWMR | Cloud water mixing ratio | kg kg-1 |
| 0 | 1 | 192 | CRAIN | Categorical rain (yes=1; no=0) | |
| 0 | 1 | 193 | CFRZR | Categorical freezing rain (yes=1; no=0) | |
| 0 | 1 | 194 | CICEP | Categorical ice pellets (yes=1; no=0) | |
| 0 | 1 | 195 | CSNOW | Categorical snow (yes=1; no=0) | |
| 0 | 1 | 196 | CPRAT | Convective precipitation rate | kg m-2 s-1 |
| 0 | 1 | 200 | PEVPR | Potential evaporation rate | W m-2 |
| 0 | 2 | 2 | U GRD | u-component of wind | m s-1 |
| 0 | 2 | 3 | V GRD | v-component of wind | m s-1 |
| 0 | 2 | 8 | V VEL | Vertical velocity (pressure) | Pa s-1 |
| 0 | 2 | 10 | ABS V | Absolute vorticity | s-1 |
| 0 | 2 | 17 | U FLX | Momentum flux, u-component | N m-2 |
| 0 | 2 | 18 | V FLX | Momentum flux, v-component | N m-2 |
| 0 | 2 | 192 | VW SH | Vertical speed shear | s-1 |
| 0 | 3 | 0 | PRES | Pressure | Pa |
| 0 | 3 | 1 | PRMSL | Pressure reduced to MSL | Pa |
| 0 | 3 | 5 | HGT | Geopotential height | gpm |
| 0 | 3 | 9 | GP A | Geopotential height anomaly | gpm |
| 0 | 3 | 193 | 5WAVH | 5-wave geopotential height | gpm |
| 0 | 3 | 194 | U-GWD | Zonal flux of gravity wave stress | N m-2 |
| 0 | 3 | 195 | V-GWD | Meridional flux of gravity wave stress | N m-2 |
| 0 | 3 | 196 | HPBL | Planetary boundary layer height | m |
| 0 | 3 | 197 | 5WAVA | 5-wave geopotential height anomaly | gpm |
| 0 | 4 | 192 | DSWRF | Downward shortwave radiation flux | W m-2 |
| 0 | 4 | 193 | USWRF | Upward shortwave radiation flux | W m-2 |
| 0 | 5 | 192 | DLWRF | Downward longwave radiation flux | W m-2 |
| 0 | 5 | 193 | ULWRF | Upward longwave radiation flux | W m-2 |
| 0 | 6 | 1 | T CDC | Total cloud cover | % |
| 0 | 6 | 6 | C WAT | Cloud water | kg m-2 |
| 0 | 6 | 193 | CWORK | Cloud workfunction | J kg-1 |
| 0 | 7 | 6 | CAPE | Convective available potential energy | J kg-1 |
| 0 | 7 | 7 | CIN | Convective inhibition | J kg-1 |
| 0 | 7 | 192 | LFT X | Surface lifted index | deg K |
| 0 | 7 | 193 | 4LFTX | Best (4 layer) lifted index | deg K |
| 0 | 14 | 0 | TOZNE | Total ozone | Dobson |
| 0 | 14 | 192 | O3MR | Ozone mixing ratio | kg kg-1 |
| 0 | 19 | 1 | ALBDO | Albedo | % |
| 2 | 0 | 0 | LAND | Land cover | |
| 2 | 0 | 5 | WATR | Water runoff | kg m-2 |
| 2 | 0 | 192 | SOILW | Volumetric soil moisture content | |
| 2 | 0 | 193 | GFLUX | Ground heat flux | W m-2 |
| 10 | 2 | 0 | ICEC | Ice cover | fraction |
用python读取数据，画某地风矢量图：主要用pygrib
