(EUV imagery of the solar disk, taken by NASA SDO)

Overview

EUVpy is a Python module that contains the NEUVAC empirical model of solar EUV irradiance for use primarily in thermosphere-ionosphere models. Conceptual development was carried out by Dr. Aaron J. Ridley and analysis and contributions were made by Dr. Daniel A. Brandt.

EUVpy also contains code for running, comparing, and analyzing the performance of NEUVAC in comparison to other empirical models such as EUVAC, HEUVAC, HFG, and FISM2. As such, the package includes access to EUVAC, HEUVAC, and HFG, and allows the user to download the F10.7 index at will.

Installation

EUVpy should run without much difficulty, but to be safe, one should install gfortran:

• gfortran ($sudo apt-get install gfortran)

You can obtain EUVpy with a simple git clone command, and the relevant modules may then be loaded as usual. If running it proves difficult, then you may wish to install the modules in the requirements.txt file. In Linux, this may be done with the command:

pip install -r requirements.txt

Usage

EUVpy contains modules for 4 different EUV irradiance models. These models include:

• NEUVAC
• EUVAC
• HEUVAC
• SOLOMON

A note about running HEUVAC in particular: The base code of HEUVAC is in Fortran, written by Dr. Phil Richards. In order to run it on a Unix-based OS, the script compile.sh should be run first. This requires gfortran, so if that is not installed on your system, please install it first. When this is completed, navigate (via terminal) to the directory empiricalModels/models/HEUVAC and do the following:

. compile.sh

This should only have to be done once. After this is completed, you can navigate back to the top directory and proceed as normal, running HEUVAC simply by calling the wrapper function in the module heuvac.py.

We note that SOLOMON in the literature can either refer to the empirical model between F10.7 and 81 day-averaged F10.7 centered on the current day (hereafter F10.7A) and EUV irradiance in 22 overlapping bands as described by Solomon and Qian 2005, or it can refer to any EUV irradiance data summed into those 22 overlapping bins (referred to as the STAN BANDS). In this package, SOLOMON only refers to the former, though functionality does exist to run all other models in the STAN BANDS.

Finding your way around

There are few folders in this package:

• empiricalModels: Contains code and data for EUVAC, HEUVAC, and SOLOMON, as well as FISM:
• experiments: Contains code and figures related to the publication associated with NEUVAC. In this folder, the file fitNeuvac.py s used for actually performing the NEUVAC fits between F10.7, F10.7A, and FISM2, while uncNeuvac.py contains code for computing the correlation matrix used to enable running NEUVAC ensembles, as well as generating plots of the squared difference between NEUVAC and FISM2 in different bands.
• measurements: Contains data from SDO/EVE and TIMED/SEE. Much of the data here isn't used at all.
• NEUVAC: Contains the code for running NEUVAC.
• solarIndices: Contains F10.7 solar index data, from both OMNIWeb and Penticton.
• tools: Contains code for miscellaneous helper functions. In this folder appears the following:
  • EUV: Contains numerous functions within fism2_process.py for reading in and rebinning FISM2 data.
  • processIndices.py: Contains functions for reading in, downloading, and cleaning OMNIWeb data.
  • processIrradiances.py: Contains functions for reading in data from TIMED/SEE, SDO/EVE, and FISM.
  • spectralAnalysis.py: Contains functions for converting between solar spectral irradiance and solar spectral flux.
  • toolbox.py: Contains miscellaneous helper functions that mainly focus on directory management, loading and saving data, statistics, and fitting.

To import any of the models, simply do as follows:

NEUVAC

from NEUVAC import neuvac

neuvacIrr, perturbedNeuvacIrr, _, _ = neuvac.neuvacEUV(F107, F107A, tableFile=neuvac_tableFile, statsFiles=['corMat.pkl', 'sigma_NEUVAC.pkl']

EUVAC

from empiricalModels.models.EUVAC import euvac

euvacFlux, euvacIrr, _, _, _ = euvac.euvac(F107, F107A)

HEUVAC

from empiricalModels.models.HEUVAC import heuvac

heuvac_wav, heuvacFlux, heuvacIrr, _, _, _ = heuvac.heuvac(F107, F107A, torr=True)

SOLOMON

from empiricalModels.models.SOLOMON import solomon

solomonFluxHFG, solomonIrrHFG = solomon.solomon(F107, F107A, model='HFG')

solomonFluxEUVAC, solomonIrrEUVAC = solomon.solomon(F107, F107A, model='EUVAC')

Please note the following for the above:

• neuvac_tableFile: Holds all the coefficients of the most recent fit of NEUVAC. The file is located here: /NEUVAC/neuvac_table.txt
• corMat.pkl: Holds the normalized correlation matrix for all the NEUVAC bands. Located in the folder 'experiments'. This is similarly true for 'corMatEUVAC.pkl' and 'corMatHEUVAC.pkl'.
• sigma_NEUVAC.pkl: Holds the normalized standard deviation of the residuals with respect to FISM2. Located in the folder 'experiments'. This is similarly true for 'sigma_EUVAC.pkl' and 'sigma_HEUVAC.pkl'.

Running any of the EUV models is straightforward, as shown in the examples below.

Examples

We encourage you to peruse the examples folder as a guide for calling the different irradiance models and displaying outputs.

Due to the unique construction of NEUVAC, at present, we only recommend running ensembles for NEUVAC, and not any of the other models.

Scientific Ethics

In using this code, depending on the module used, proper citations should be given to the original authors responsible for developing each model or dataset:

NEUVAC: Brandt and Ridley, in review

EUVAC: Richards, et al. 1994

HEUVAC Richards, et al. 2006

SOLOMON Solomon and Qian, 2005

FISM2: Chamberlin, et al. 2020