The python scripts provided here downloads OMNI data from the NASA website, compiles the data for all the years, and provides a single netCDF file as output.
This code depends on the numpy and netCDF4 python libraries to work properly. Pip install netCDF4 from the terminal if missing:
> pip install netCDF4
numpy should either have shipped with your Python Anaconda install, else may be best installed using a binary package. Refer to https://scipy.org/install.html
> import gof
> gof.generateOmniFile(startYear = 1995, endYear = 2005, resolution = "high", outputFile= "myOutputFile.nc")
The above call will generate a netCDF file named myOutputFile.nc containing high resolution (5 minute) OMNI data between years 1995 and 2005. Setting startYear and endYear to the same value will download a year's worth of data.
The function definition provides default values that are used when the function is called with one or more parameters missing:
generateOmniFile(startYear=1963, endYear=datetime.datetime.now().year, resolution='low', hroRes = 5,
modFlag=False, outputFile='defaultOutput', writeOutput=True, cleanUp=True)
Therefore, the call
gof.generateOmniFile()
will produce a file named 'OMNI_1963_<currentYear>_low_resolution.nc' containing unmodified low resolution OMNI data from 1963 to the current year. The modFlag keyword allows the user to switch between the original and derived low resolution OMNI data products. This keyword is ignored when the resolution keyword is set to high. Similarly, the hroRes allows users to switch between 1 and 5 minute high resolution OMNI data, and the keyword is ignored when the resolution is set to low. More information regarding the low and high resolution OMNI data and their sub-flavours can be found in the appropriate READMEs available in this repository.
The cleanUp keyword may be set to False if the user wishes to retain the raw data files downloaded by the script. These will be stored in the ./~tmp folder, created by the script in the same folder where it is located. If the folder previously exists, its contents are first wiped.
The writeOutput keyword was added for users who may want to download the OMNI data using this script but not want a netCDF file to be generated. Setting both writeOutput and cleanUp to False will allow users to do this.
" The /data/omni/low_res_omni/ directory contains the hourly mean values of the interplanetary magnetic field (IMF) and solar wind plasma parameters measured by various spacecraft near the Earth's orbit, as well as geomagnetic and solar activity indices, and energetic proton fluxes known as OMNI2 data. "
" This directory (ftp://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/) provides access to high resolution OMNI (HRO) data at 1-min and 5-min resolution and to related 1-min resolution spacecraft-specific data sets. The latter consist of ACE, Wind and IMP 8 field and plasma data sets shifted to the bow shock nose, initially for 1995-2006, by a specific combination of Minimum Variance and Cross Product techniques. The latter also consists of 1998-2000 ACE data shifted to Wind by each of four techniques."