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Generates datasets of historical wind data, dumping it to binary file for easy querying.

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Historical Winds Aloft

To build this dataset, you need to first download the uwnd and vwnd 4X daily long term average datasets from the following URL:

ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.derived/pressure/uwnd.4Xday.1981-2010.ltm.nc ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.derived/pressure/vwnd.4Xday.1981-2010.ltm.nc

You then need to concatenate these two files together using the ncks tools (NetCDF operators):

cp vwnd.4Xday.1981-2010.ltm.nc vwnd
ncks -A uwnd.4Xday.1981-2010.ltm.nc vwnd
mv vwnd wnd.4Xday.1981-2010.ltm.nc

interpolate.py will use the pressure surfaces within the wnd file to calculate any desired pressure level you want, dumping the result to a binary file that you specify. In an ISA standard atmosphere:

  Feet     Millibar
  8000   =   753
  10000  =   697
  15000  =   572
  18000  =   506
  21000  =   446
  24000  =   393
  27000  =   344
  30000  =   301
  33000  =   262
  36000  =   227
  39000  =   196
  42000  =   170

Pick the millibar value according to the pressure altitude in feet you want. Say, 10000ft:

python interpolate.py 697 wnd.4Xday.1981-2010.ltm.nc 10000.bin

That will interpolate the source data to create the outputs for 10000ft, dumping it in the 10000.bin file.

To query it, use windspd.py:

$ python windspd.py 10000.bin

File looks good! Covers lat range [90.0, -90.0] and long range [0.0, 357.5]. Step size 2.5 degrees. 73.0 rows and 144.0 cols. Cycle range [1,1460].
Enter a date string (MM/DD/YYYY). Leave blank for today:
OK! Date = 09/10/2016, Day of year = 254
Cycle within day? ( 1 = 00Z, 2 = 06Z, 3 = 12Z, 4 = 18Z): 4
What latitude?: 40
What longitude?: 170
20 68
Spd Offset: 42690523.0
Dirn Offset: 42690525.0
[1015.0, 20, 68] = 19.02kts @ 92.71deg
Enter a date string (MM/DD/YYYY). Leave blank for today:
OK! Date = 09/10/2016, Day of year = 254
Cycle within day? ( 1 = 00Z, 2 = 06Z, 3 = 12Z, 4 = 18Z): ^C
Bye!

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Generates datasets of historical wind data, dumping it to binary file for easy querying.

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