Windows上python读取grib2文件（不用Linux）

最近在网上下载的NCEP的fnl数据，发现只有grib2文件格式。因为现在处理数据使用的更多的是python，matlab一类的。网上一搜python读取grib文件需要依赖pygrib库，pygrib是欧洲中期天气预报中心(ECMWF)的GRIG API C库的Python接口，通过这个库就可以将Grib数据读取出来。但这个依赖库只有Linux、Mac OS系统下可以使用，Windows系统没有这个依赖库，因此Windows下python不能直接读取grib文件。但python可以处理nc文件，想办法把grib文件转化为nc文件，就可以方便处理了。先说方法，主要有两种方案，一种是安装Cygwin，可以直接处理。另一种是安装wgrib2，转化数据。

1.读取grib2的两种方案

1.1下载安装Cygwin

下载安装Cygwin，Cygwin是一个在windows平台上运行的类UNIX模拟环境，就等于是一个Linux的模拟器，这样就可以下载pygrib依赖库处理grib2文件，本人不喜欢用这种模拟器，众所周知，模拟器容易卡卡卡。因此，主要讲述第二种方法。

1.2下载安装wgrib2

因为最新的数据都是grib2文件了，所以直接下载wgrib2。（如果需要处理的是grib文件，则下载wgrib）
下载wgrib2链接：ftp://ftp.cpc.ncep.noaa.gov/wd51we/wgrib2/Windows_64/这里直接是Windows 64的链接，如果需要别的版本可以下载对应的版本。(最近有人反映网站改成ftp链接打开了，所以我把我下载的上传成资源，wgrib2相关安装文件.rar)。
主要下载的东西：
你可以先下载wgrib2.exe，运行的时候会提示缺少啥，对应下载啥。
下载安装成功后，在cmd下对应的wgrib2文件夹下运行wgrib2.exe，就会看到对应得数据参数选项。

对应得所有功能如下，只是一个展示，不需要细看：

wgrib2 v0.2.0.9b1 3/2019  Wesley Ebisuzaki, Reinoud Bokhorst, John Howard, Jaakko Hyvätti, Dusan Jovic, Daniel Lee, Kristian Nilssen, Karl Pfeiffer, Pablo Romero, Manfred Schwarb, Gregor Schee, Arlindo da Silva, Niklas Sondell, Sam Trahan, Sergey Varlamovstock build-else            else         else-elseif_fs       elif  X      elseif X (fixed string) conditional execution-elseif_n        elif  X      elseif (inv numbers in range), X=(start:end:step)-elseif_rec      elif  X      elseif (record numbers in range), X=(start:end:step)-elseif_reg      elif  X      elseif rpn registers defined, X = A, A:B, A:B:C, etc A = register number-elseif          elif  X      elseif X (POSIX regular expression) conditional on match-endif           endif        endif-if              if    X      if X (POSIX regular expression), conditional execution on match-if_fs           if    X      if X (fixed string), conditional execution on match-if_n            if    X      if (inv numbers in range), X=(start:end:step)-if_rec          if    X      if (record numbers in range), X=(start:end:step)-if_reg          if    X      if rpn registers defined, X = A, A:B, A:B:C, etc A = register number-not_if          if    X      not_if X (regular expression), conditional execution on not match-not_if_fs       if    X      if X (fixed string) does not match, conditional execution up to next output/fi-0xSec           inv   X      Hex dump of section X (0..8)-aerosol_size    inv          optical properties of an aerosol-aerosol_wavelength inv          optical properties of an aerosol-bitmap          inv          bitmap mode-center          inv          center-checksum        inv   X      CRC checksum of section X (0..8), whole message (X = -1/message) or (X=data)-disc            inv          discipline (code table 0.0)-domain          inv          find rectangular domain for g2ctl/GrADS plots-end_ft          inv          verf time = reference_time + forecast_time + stat. proc time (YYYYMMDDHH) (same as -vt)-end_FT          inv          verf time = reference_time + forecast_time + stat. proc time (YYYYMMDDHHMMSS) (same as -VT)-ens             inv          ensemble information-ext_name        inv          extended name, var+qualifiers-ftime           inv          either ftime1 or ftime2 dep on version_ftime-ftime1          inv          forecast time-ftime2          inv          timestamp -- will replace -ftime in the future TESTING-ftn_api_fn0     inv          n npnts nx ny msg_no submsg i11,5(1x,i11)-full_name       inv          extended name, var+qualifiers-gdt             inv          contents of Grid Definition Template (g2c)-get_byte        inv   X Y Z  get bytes in Section X, Octet Y, number of bytes Z (decimal format)-get_hex         inv   X Y Z  get bytes in Section X, Octet Y, number of bytes Z (bytes in hexadecimal format)-get_ieee        inv   X Y Z  get ieee float in Section X, Octet Y, number of floats Z-get_int         inv   X Y Z  get 4-byte ints in Section X, Octet Y, number of ints Z-get_int2        inv   X Y Z  get 2-byte ints in Section X, Octet Y, number of ints Z-grib_max_bits   inv          maximum bits used in grib encoding-grid            inv          grid definition-grid_id         inv          show values from grid_id-hybrid          inv          shows vertical coordinate parameters from Sec4-ij              inv   X Y    value of field at grid(X,Y) X=1,..,nx Y=1,..,ny (WxText enabled)-ijlat           inv   X Y    lat,lon and grid value at grid(X,Y) X=1,..,nx Y=1,..,ny (WxText enabled)-ilat            inv   X      lat,lon and grid value at Xth grid point, X=1,..,npnts (WxText enabled)-JMA             inv          inventory for JMA locally defined PDT-lev             inv          level (code table 4.5)-ll2i            inv   X Y    x=lon y=lat, converts to (i), 1..ndata-ll2ij           inv   X Y    x=lon y=lat, converts lon-lat to (i,j) using gctpc-lon             inv   X Y    value at grid point nearest lon=X lat=Y (WxText enabled)-match_inv       inv          inventory used by -match, -not, -if and -not_if-Match_inv       inv          same as -match_inv except d=YYYYMMDDHH <-> D=YYYYMMDDHHmmss-max             inv          print maximum value-min             inv          print minimum value-misc            inv          variable name qualifiers like chemical, ensemble, probability, etc-MM              inv          reference time MM-model_version_date inv          prints model date code-n               inv          prints out inventory number-N_ens           inv          number of ensemble members-nl              inv          inserts new line into inventory-nlons           inv          number of longitudes for each latitude-npts            inv          number of grid points-nxny            inv          nx and ny of grid-packing         inv          shows the packing mode (use -v for more details)-pdt             inv          Product Definition Table (Code Table 4.0)-precision       inv          precision of packing-print           inv   X      inserts string (X) into inventory-prob            inv          probability information-process         inv          Process (code table 4.3)-processid       inv          process id (locally defined)-proj4_ij2ll     inv   X Y    X=x Y=y, converts to (i,j) to lon-lat using proj.4 (experimental) we:sn-proj4_ll2i      inv   X Y    x=lon y=lat, converts to (i) using proj.4 (experimental) 1..ndata-proj4_ll2ij     inv   X Y    x=lon y=lat, converts lon-lat (i,j) using proj.4 (experimental)-radius          inv          radius of Earth-range           inv          print out location of record in bytes, 0 = first byte-RT              inv          type of reference Time-s               inv          simple inventory-S               inv          simple inventory with minutes and seconds (subject to change)-s2              inv          simple inventory .. for testing ftime2-scale           inv          scale for packing-scaling         inv          scaling for packing (old format)-scan            inv          scan order of grid-Sec_len         inv          length of various grib sections-Sec0            inv          contents of section0-Sec3            inv          contents of section 3 (Grid Definition Section)-Sec4            inv          Sec 4 values (Product definition section)-Sec5            inv          Sec 5 values (Data representation section)-Sec6            inv          show bit-map section-spatial_proc    inv          show spacial processing, pdt=4.15-spectral_bands  inv          spectral bands for satellite, pdt=4.31 or 4.32-start_ft        inv          verf time = reference_time + forecast_time (YYYYMMDDHH) : no stat. proc time-start_FT        inv          verf time = reference_time + forecast_time (YYYYMMDDHHMMSS) - no stat. proc time-stats           inv          statistical summary of data values-subcenter       inv          subcenter-t               inv          reference time YYYYMMDDHH, -v2 for alt format-T               inv          reference time YYYYMMDDHHMMSS-table           inv          parameter table-timer           inv          reads OpenMP timer-unix_time       inv          print unix timestamp for rt & vt-V               inv          diagnostic output-var             inv          short variable name-varX            inv          raw variable name - discipline mastertab localtab center parmcat parmnum-vector_dir      inv          grid or earth relative winds-verf            inv          simple inventory using verification time-vt              inv          verf time = reference_time + forecast_time, -v2 for alt format-VT              inv          verf time = reference_time + forecast_time (YYYYMMDDHHMMSS)-warn_old_g2     inv          warn if old g2lib would have problem-wave_partition  inv          ocean surface wave partition (pdt=4.52)-YY              inv          reference time YYYY-inv_f77         inv>  X Y Z  match inventory written to Z with character*(Y) and X=(bin,ieee)-last            inv>  X      write last inv item to file X-last0           inv>  X      write last inv item to beginning of file X-nl_out          inv>  X      write new line in file X-print_out       inv>  X Y    prints string (X) in file (Y)-s_out           inv>  X      simple inventory written to X-big_endian      misc         sets ieee output to big endian (default is big endian)-box_ave         misc  X Y Z  box average X=odd integer (lon) Y=odd integer (lat) critical_weight-colon           misc  X      replace item deliminator (:) with X-config          misc         shows the configuration-count           misc         prints count, number times this -count was processed-end             misc         stop after first (sub)message (save time)-error_final     misc  X Y Z  error if at end X=count Y=ne,eq,le,lt,gt,ge Z=integer-fix_CFSv2_fcst  misc  X Y Z  fixes CFSv2 monthly fcst X=daily or 00/06/12/18 Y=pert no. Z=number ens fcsts v1.0-fix_ncep        misc         fix ncep PDT=8 headers produced by cnvgrib-gctpc           misc  X       X=0,1 use gctpc library (default=1)-grid_changes    misc         prints number of grid changes-grid_def        misc         read lon and lat data from grib file -- experimental-h               misc         help, shows common options-header          misc         f77 header or nx-ny header in text output (default)-help            misc  X      help [search string|all], -help all, shows all options-ijundefine      misc  X Y Z  sets grid point values to undefined X=(in-box|out-box) Y=ix0:ix1 Z=iy0:iy1 ix=(1..nx) iy=(1..ny)-import_bin      misc  X      read binary file (X) for data-import_grib     misc  X      read grib2 file (X) for data-import_grib_fs  misc  X Y    read grib2 file (Y) sequentially for record that matches X (fixed string)-import_ieee     misc  X      read ieee file (X) for data-import_netcdf   misc  X Y Z  TESTING X=file Y=var Z=hyper-cube specification-import_text     misc  X      read text file (X) for data-limit           misc  X      stops after X fields decoded-little_endian   misc         sets ieee output to little endian (default is big endian)-mem_del         misc  X      delete mem file X-mem_final       misc  X Y    write mem file X to file Y at cleanup step-mem_init        misc  X Y    read mem file X from file Y (on initialization)-ndate           misc  X Y    X=date Y=dt print date + dt-ndates          misc  X Y Z  X=date0 Y=(date1|dt1) Z=dt2 for (date=date0; date<(date1|date0+dt1); date+=dt2) print date-ndates_fmt      misc  X      X = C format for ndates option-new_grid_interpolation misc  X      new_grid interpolation X=bilinear,bicubic,neighbor,budget-new_grid_ipopt  misc  X      new_grid ipopt values X=i1:i2..:iN N <= 20-new_grid_vectors misc  X      change fields to vector interpolate: X=none,default,UGRD:VGRD,(U:V list)-new_grid_winds  misc  X      new_grid wind orientation: X = grid, earth (no default)-no_header       misc         no f77 header or nx-ny header in text output-proj4           misc  X      X=0,1 use proj4 library for geolocation (testing)-rewind_final    misc  X      rewinds file X on cleanup step if already opened, CW2-rewind_proc     misc  X      rewinds file X on processing step if already opened, CW2-rpn             misc  X      reverse polish notation calculator-rpn_rcl         misc  X      data = register X .. same as -rpn rcl_X .. no geolocation calc needed-rpn_sto         misc  X      register X = data.. same as -rpn sto_X .. no geolocation calc needed-scaling_0001    misc         changes scaling testing (sample)-set             misc  X Y    set X = Y, X=local_table,etc (help: -set help help)-set_ave         misc  X      set ave/acc .. only use on pdt=4.0/4.8 (old code)-set_bin_prec    misc  X      X use X bits and ECMWF-style grib encoding-set_bitmap      misc  X      use bitmap when creating complex packed files X=1/0-set_byte        misc  X Y Z  set bytes in Section X, Octet Y, bytes Z (a|a:b:c)-set_date        misc  X      changes date code, X=(+|-)N(hr|dy|mo|yr), YYYYMMDDHHmmSS-set_ens_num     misc  X Y Z  convert PDT 0,1 -> 1, 8,11 -> 11, X=code table 4.6 Y=pert num Z=num ens members -1=No Change-set_ensm_derived_fcst misc  X Y    convert PDT 0,1,2 -> 2, 8,11,12 -> 12, X=code table 4.7 Y=num ens members-set_ftime       misc  X      either set_ftime1 or set_ftime2 dep on version_ftime-set_ftime1      misc  X      set ftime-set_ftime2      misc  X      set ftime2 .. will be replace -set_ftime/ave in the future -- TESTING ----set_grib_max_bits misc  X      sets scaling so number of bits does not exceed N in (new) grib output-set_grib_type   misc  X      set grib type = jpeg, simple, ieee, complex(1|2|3), aec, same-set_hex         misc  X Y Z  set bytes in Section X, Octet Y, bytes Z (a|a:b:c|abc) in hexadecimal-set_ieee        misc  X Y Z  set ieee float in Section X, Octet Y, floats Z (a|a:b:c)-set_ijval       misc  X Y Z  sets grid point value X=ix Y=iy Z=val-set_int         misc  X Y Z  set 4-byte ints in Section X, Octet Y, signed integers Z (a|a:b:c)-set_int2        misc  X Y Z  set 2-byte ints in Section X, Octet Y, signed integers Z (a|a:b:c)-set_ival        misc  X Y    sets grid point value X=i1:i2:.. Y=va1:val2:.. grid[i1] = val1,etc-set_lev         misc  X      changes level code .. not complete-set_metadata    misc  X      read meta-data for grib writing from file X-set_metadata_str misc  X      X = metadata string-set_pdt         misc  X      makes new pdt, X=(+)PDT_number or X=(+)PDT_number:size of PDT in octets, +=copy metadata-set_percentile  misc  X      convert PDT 0..6 -> 6, 8..15 -> 10, X=percentile (0..100)-set_prob        misc  5 args X/Y forecasts Z=Code Table 4.9 A=lower limit B=upper limit-set_radius      misc  X      set radius of Earth X= 0,2,4,5,6,8,9 (Code Table 3.2), 1:radius , 7:major:minor-set_scaling     misc  X Y    set decimal scaling=X/same binary scaling=Y/same new grib messages-set_sec_size    misc  X Y    resizes section , X=section number, Y=size in octets, DANGEROUS-set_ts_dates    misc  X Y Z  changes date code for time series X=YYYYMMDDHH(mmss) Y=dtime Z=#msgs/date-set_var         misc  X      changes variable name-start_timer     misc         starts OpenMP timer-status          misc  X      X X=file-submsg          misc  X      process submessage X (0=process all messages)-sys             misc  X      run system/shell command, X=shell command-text_col        misc  X      number of columns on text output-text_fmt        misc  X      format for text output (C)-udf             misc  X Y    run UDF, X=program+optional_args, Y=return file-udf_arg         misc  X Y    add grib-data to UDF argument file, X=file Y=name-undefine        misc  X Y Z  sets grid point values to undefined X=(in-box|out-box) Y=lon0:lon1 Z=lat0:lat1-undefine_val    misc  X      grid point set to undefined if X=val or X=low:high-v               misc         verbose (v=1)-v0              misc         not verbose (v=0)-v2              misc         really verbose (v=2)-version         misc         print version--version        misc         print version-AAIG            out          writes Ascii ArcInfo Grid file, lat-lon grid only (alpha)-AAIGlong        out          writes Ascii ArcInfo Grid file, lat-lon grid only long-name *.asc (alpha)-ave             out   X Y    average X=time step Y=output v2-ave_var         out   X Y    average/std dev/min/max X=time step, Y=output-ave0            out   X Y    average X=time step, Y=output grib file needs file is special order-bin             out   X      write binary data to X-cress_lola      out   X..Z,A lon-lat grid values X=lon0:nlon:dlon Y=lat0:nlat:dlat Z=file A=radius1:radius2:..:radiusN-csv             out   X      make comma separated file, X=file (WxText enabled)-csv_long        out   X      make comma separated file, X=file (WxText enabled)-cubeface2global out   X Y    write faces X as global cubed grid to Y: X=list of faces to exclude-ens_processing  out   X Y    ave/min/max/spread X=output Y=future use-fcst_ave        out   X Y    average X=time step Y=output v2-fcst_ave0       out   X Y    average X=time step, Y=output grib file needs file is special order-fi              out          depreceated-grib            out   X      writes GRIB record (one submessage) to X-GRIB            out   X      writes entire GRIB record (all submessages)-grib_ieee       out   X      writes data[] to X.grb, X.head, X.tail, and X.h-grib_out        out   X      writes decoded/modified data in grib-2 format to file X-grib_out_irr    out   X Y    writes irregular grid grib (GDT=130 not adopted) X=(all|defined) Y=(output file)-grib_out_irr2   out   5 args writes irregular grid grib GDT 101 X=npnts Y=grid_no Z=grid_ref A=UUID B=(output file)-gridout         out   X      text file with grid: i j lat lon (1st record)-ieee            out   X      write (default:big-endian) IEEE data to X-ijbox           out   X..Z,A grid values in bounding box X=i1:i2[:di] Y=j1:j2[:dj] Z=file A=[bin|text|spread]-ijsmall_grib    out   X Y Z  make small domain grib file X=ix0:ix1 Y=iy0:iy1 Z=file-irr_grid        out   X Y Z  make irregular grid (GDT=130 not adopted), nearest neighbor, X=lon-lat list Y=radius (km) Z=output grib file-lola            out   X..Z,A lon-lat grid values X=lon0:nlon:dlon Y=lat0:nlat:dlat Z=file A=[bin|text|spread|grib]-merge_fcst      out   X Y    merge forecast ave/acc/min/max X=number to intervals to merge (0=every) Y=output grib file-mysql           out   5 args H=[host] U=[user] P=[password] D=[db] T=[table]-mysql_dump      out   7 args H=[host] U=[user] P=[password] D=[db] T=[table] W=[western_lons:0|1] PV=[remove unlikely:0|1]-mysql_speed     out   7 args H=[host] U=[user] P=[password] D=[db] T=[table] W=[western_lons:0|1] PV=[remove unlikely:0|1]-ncep_norm       out   X      normalize NCEP-type ave/acc X=output grib file-ncep_uv         out   X      combine U and V fields into one message like NCEP operations-netcdf          out   X      write netcdf data to X-new_grid        out   X..Z,A bilinear interpolate: X=projection Y=x0:nx:dx Z=y0:ny:dy A=grib_file alpha-reduced_gaussian_grid out   X Y Z  reduced Gaussian grid, X=outputfile Y=-1 Z=(neighbor|linear)[-extrapolate]-small_grib      out   X Y Z  make small domain grib file X=lonW:lonE Y=latS:latN Z=file-spread          out   X      write text - spread sheet format into X (WxText enabled)-submsg_uv       out   X      combine vector fields into one message-text            out   X      write text data into X-time_processing out   X..Z,A average X=CodeTable 4.10 Y=CodeTable 4.11 Z=time step A=output-tosubmsg        out   X      convert GRIB message to submessage and write to file X-wind_dir        out   X      calculate wind direction, X = output gribfile (direction in degrees, 0=wind from north, 90=wind from east)-wind_speed      out   X      calculate wind speed, X = output gribfile (U then V in datafile)-wind_uv         out   X      calculate UGRD/VGRD from speed/dir, X = output gribfile-alarm           init  X      terminate after X seconds-append          init         append mode, write to existing output files-crlf            init         make the end of the inventory a crlf (windows) instead of newline (unix)-d               init  X      dump message X (n or n.m), only 1 -d allowed-egrep           init  X      egrep X | wgrib2 (X is POSIX regular expression)-egrep_v         init  X      egrep -v X | wgrib2 (X is POSIX regular expression)-eof_bin         init  X Y    send (binary) integer to file upon EOF: X=file Y=integer-eof_string      init  X Y    send string to file upon EOF: X=file Y=string-err_bin         init  X Y    send (binary) integer to file upon err exit: X=file Y=integer-err_string      init  X Y    send string to file upon err exit: X=file Y=string-fgrep           init  X      fgrep X | wgrib2-fgrep_v         init  X      fgrep -v X | wgrib2-fix_ncep_2      init         ncep bug fix 2, probability observation < -ve number-fix_ncep_3      init         sets flag to fix ncep bug 3 (constant fields)-fix_ncep_4      init         fixes NCEP grib2 files where DX and DY are undefined-for             init  X      process record numbers in range, X=(start:end:step), only one -for allowed-for_n           init  X      process inv numbers in range, X=(start:end:step), only one -for allowed-g2clib          init  X      X=0/1/2 0=WMO std 1=emulate g2clib 2=use g2clib-i               init         read Inventory from stdin-i_file          init  X      read Inventory from file-inv             init  X      write inventory to X-match           init  X      process data that matches X (POSIX regular expression)-match_fs        init  X      process data that matches X (fixed string)-match_inv_add   init  X Y Z  add new options to match_inventory-nc_grads        init         require netcdf file to be grads v1.9b4 compatible (fixed time step only)-nc_nlev         init  X      netcdf, X = max LEV dimension for {TIME,LEV,LAT,LON} data-nc_pack         init  X      pack/check limits of all NEW input variables, X=min:max[:byte|short|float]-nc_table        init  X      X is conversion_to_netcdf_table file name-nc_time         init  X      netcdf, [[-]yyyymmddhhnnss]:[dt{s[ec]|m[in]|h[our]|d[ay]}], [-] is for time alignment only-nc3             init         use netcdf3 (classic)-nc4             init         use netcdf4 (compressed, controlled endianness etc)-ncpu            init  X      number of threads, default is environment variable OMP_NUM_THREADS/number of cpus-no_append       init         not append mode, write to new output files (default)-no_nc_grads     init         netcdf file may be not grads v1.9b4 compatible, variable time step-no_nc_pack      init         no packing in netcdf for NEW variables-no_nc_table     init         disable previously defined conversion_to_netcdf_table-no_nc_time      init         netcdf, disable previously defined initial or relative date and time step-not             init  X      process data that does not match X (POSIX regular expression)-not_fs          init  X      process data that does not match X (fixed string)-one_line        init         puts all on one line (makes into inventory format)-order           init  X      decoded data in X (raw|we:sn|we:ns) order, we:sn is default-persistent      init  X      makes file X persistent if already opened (default on open), CW2-rewind_init     init  X      rewinds file X on initialization if already opened, CW2-set_ext_name    init  X      X=0/1 extended name on/off-set_regex       init  X      set regex mode X = 0:extended regex (default) 1:pattern 2:extended regex & quote metacharacters-set_version_ftime init  X      set version of ftime X=1, 2-tigge           init         use modified-TIGGE grib table-transient       init  X      make file X transient, CW2

然后根据网上的两个例子，去使用wgrib2读取grib2数据。

1.2.1按编号读取

import os
# 将当前目录转到wgrib2工具目录
os.chdir("C:\\wgrib2")
# 执行cmd命令，查看各个“小房间”具体信息
#os.system(r"wgrib2 C:\\download\\fnl_20200327_00_00.grib2 -v")

结果：
可以看到数据信息，我们读第17号，温度信息，读到txt文件中。

os.system(r"wgrib2 C:\\download\\fnl_20200327_00_00.grib2 -d 17 -text C:\\download\\test.txt

结果如下：
这样python就可以直接处理txt文件。

1.2.2 按名称匹配读取

这种方法用的较多，因为气象变量的名称是不会变的，就不需要去找仓库号，这次把结果转成csv文件。

# 进行气象变量名称匹配,读取2m处温度这个气象变量到2m_tmp.csv文件中
#os.system("wgrib2 C:\\download\\fnl_20200327_00_00.grib2 -match ':TMP:2 m' -csv C:\\download\\2m_tmp.csv")

结果如下：
这样，我们就通过wgrib2将grib2数据转化为txt或者csv文件，这样就可以方便使用python处理。但是，这样我只能看部分数据，我想要的是能看到整个文件的数据，看网上关于wgrib2也没有能直接读取出来全部数据的。
最后看wgrib2的时候看到了它的一条命令：

这样，就可以通过命令把数据转化为nc文件，这样就可以用python直接读取。
下面看一下它的用法：

wgrib2 ../example/eta.t00z.awphys18.grb2 -netcdf eta.nc

具体的用法，可以详细了解wgrib2官网关于netcdf的用法https://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/netcdf.html

os.system(r"wgrib2 C:\\download\\fnl_20200327_00_00.grib2 -netcdf C:\\download\\test.nc"

这样就将grib文件转化为nc文件，方便处理。

2.python处理nc文件

python处理nc文件，需要下载依赖库：

pip install netCDF4

简单的一些操作如下：

from netCDF4 import Dataset
import numpy as npnc_obj = Dataset('C:\\wgrib2\\test.nc')
#查看nc文件
print(nc_obj)
print('---------------------------------------')#查看nc文件中的变量
print(nc_obj.variables.keys())
for i in nc_obj.variables.keys():print(i)
print('---------------------------------------')# 查看nc文件中的变量
print(nc_obj.variables.keys())
print('---------------------------------------')# 查看每个变量的信息
for i in nc_obj.variables.keys ():print("---------------------------------")print(nc_obj.variables[i])
print('---------------------------------------')# 查看每个变量的所有属性
for i in nc_obj.variables.keys ():print(nc_obj.variables[i].ncattrs())
print('---------------------------------------')# 查看每个变量的单位
for i in nc_obj.variables.keys():print(nc_obj.variables[i].units)
print('---------------------------------------')# 查看每个变量的维数
for i in nc_obj.variables.keys():print(nc_obj.variables[i].ndim)
print('---------------------------------------')# 查看每个变量的形状（维度）
for i in nc_obj.variables.keys():print(nc_obj.variables[i].shape)print('---------------------------------------')
#取出变量blh  10 metre U wind component(10米U风分量)
u10 = nc_obj['TMP_550mb'][:]
print(u10)print(np.max(u10), np.min(u10))# 读取数据值
print("读取数据值")
for i in nc_obj.variables.keys():print('--------------------------------------------------------------------------------------------------------------')print(nc_obj.variables[i][:5])

只要转成nc文件了，就可以随便看需要了解的信息，目的就达到了，只要转化为python能处理的数据，就简单多了。

由于最近那个wgrib2网站无法打开，可以参考新的方法使用python读取grib文件，在Windows下使用xarray+cfgrib读取grib文件更加方便，不用转化nc文件，参考Windows下xarray+cfgrib读取grib文件。