wind

Visualize GFS winds from NOMADS file in GRIB format

• wind -- notebook
• particle trails -- notebook

There are 2 code options for processing GRIB data: NCAR or ECMWF (both have Python APIs). I'm using the NCAR code, PyNIO.

• Data -- description of GRIB data format
• PyNIO -- instructions to install and run

Process GRIB file

To create data.json with wind vectors

$ make

To print some metadata (including date of the forecast)

$ make metadata

To list all the variables in the GRIB file

$ make list 

Source data

• GRIB
  • The date part of the filename.
  • GRIB files have wind for 8 level types. Relevant metadata is in the filename. For example:
    • UGRD_P0_L6_GLL0 # maximum wind level -- (1)
    • UGRD_P0_L7_GLL0 # tropopause -- (1)
    • UGRD_P0_L100_GLL0 # isobaric surface -- (31)
    • UGRD_P0_L102_GLL0 # specified altitude above sea level (m) -- (3) -- lv_AMSL1: [1829..3658]
    • UGRD_P0_L103_GLL0 # specified height above ground (m) -- (6) -- lv_HTGL7: [20..100]
    • UGRD_P0_L104_GLL0 # Sigma level (sigma value) -- (1)
    • UGRD_P0_2L108_GLL0 # Level at specified pressure difference from ground to level (Pa) -- (1)
    • UGRD_P0_L109_GLL0 # Potential vorticity (K m2 kg-1 s-1) -- (2)
  • Two levels: height of maximum wind, height of tropopause
  • Height of maximum wind is available in pressure (Pa) and ICAO standard atmosphere reference height (m)
  • Height of maximum wind and height of tropopoause in (m) use ICAO standard atmosphere reference height
• ICAO
  • The International Civil Aviation Organization (ICAO) published an "ICAO Standard Atmosphere" in 1993.
  • It has the same model as the ISA, but extends the altitude coverage to 80 kilometers (262,500 feet)
  • The ICAO Standard Atmosphere, like the ISA, does not contain water vapor.

PyNIO

Installed PyNIO as directed with a separate conda environment. The PyNIO github site is well documented.

$ conda create --name pynio_env --channel conda-forge pynio
$ source activate pynio_env

To use it, first activate the environment, and deactivate when done:

$ conda activate pynio_env
$ python
>>> import Nio
>>> print(Nio.__version)
>>> print(Nio.__doc__)
$ conda deactivate

• PyNIO API docs -- ucar.edu
  • Filename extension indicates expected format
  • For GRIB 1 & 2: .gr, .gr1, .grb, .grib, .grb1, .grib1, .gr2, .grb2, .grib2

References

• GRIB encoding
  • GRIB2 encoding details -- weather.gov
• turbulence, etc.
  • Unnoficial display of World Area Forecast System (WAFS) -- noaa.gov
    • APPROVED ACCESS ONLY for data
  • North American Rapid Refresh Ensemble (NARRE) -- noaa.gov
    • Has icing, turbulence, jet streem convection from ensemble models
  • NEXRAD radar -- NCDC products
  • assessment of graphical turbulence (PDF) -- noaa.gov
• GRIB -- wikipedia
• ecCodes -- ecmwf.int
  • ECMWF tools for GRIB, BUFR and WMS GTS (documentation uses Atlassian)
  • These tools need to be compiled with cmake. Python bindings exist. Linux recommended; no Windows support.
  • Python 3 interface for ecCodes -- ecmf.int
  • GRIB tools (deprecated) -- ecmwf.int
• NOMADS -- ncep.noaa.gov
  • model changes
  • GFS documentation
  • Performance statistics
• podpac -- github
  • gfs.ipynb -- github
• pynio -- github
  • PyNIO -- ucar.edu
  • Includes install instructions using conda
• grib2json -- github
  • older java implementation
• PyNGL -- ucar.edu
  • 2D visualization of climate and weather data in Python
  • pyngl -- github
  • PYNGL gallery -- gallery
• Managing environments -- docs.conda.io
• International Standard Atmosphere (ISA)
• Visualization
  • cambecc earth -- github
  • Esri version -- github
• [GRIB WW3 data viz with python](https://polar.ncep.noaa.gov/waves/examples/usingpython.shtml#example_2() -- ncep.noaa.gov