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Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes.

Pakhotin IP, Drozdov AY, Shprits YY, Boynton RJ, Subbotin DA, Balikhin MA - J Geophys Res Space Phys (2014)

Bottom Line: The coupled system has been tested for three extended time periods totalling several weeks of observations.The model has successfully simulated energetic electron fluxes for various magnetospheric conditions.Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Automatic Control and Systems Engineering, University of Sheffield Sheffield, UK.

ABSTRACT

This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes for various magnetospheric conditions. Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed.

No MeSH data available.


For 1–25 August 2013, > 800 keV flux at geosynchronous orbit (blue) versus model (red). Black crosses mark scaled NARMAX predictions for the days shown.
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fig04: For 1–25 August 2013, > 800 keV flux at geosynchronous orbit (blue) versus model (red). Black crosses mark scaled NARMAX predictions for the days shown.

Mentions: Figure 4 shows GOES-13 fluxes for the > 800 keV channel compared with fluxes predicted by VNC. Differential fluxes were obtained for two energies—891 keV and 1 MeV—and used to calculate > 800 keV integral fluxes assuming exponential energy distributions. It can be seen that, absent some underestimations at periods of rapid flux decrease, the model follows the data reasonably well. The same analysis was performed on the 1–23 September 2013 time interval, with the results visible on Figure 5. As noted above, the sinusoidal flux variation is a diurnal effect due to the spacecraft traversing different L* regions at different magnetic local times. Black crosses on the Figures 4 and 5 show NARMAX predictions for those time periods. It can be seen that NARMAX predicts variations quite well at geostationary orbit and can be successfully used for outer boundary information as an input to the VERB system.


Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes.

Pakhotin IP, Drozdov AY, Shprits YY, Boynton RJ, Subbotin DA, Balikhin MA - J Geophys Res Space Phys (2014)

For 1–25 August 2013, > 800 keV flux at geosynchronous orbit (blue) versus model (red). Black crosses mark scaled NARMAX predictions for the days shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4497480&req=5

fig04: For 1–25 August 2013, > 800 keV flux at geosynchronous orbit (blue) versus model (red). Black crosses mark scaled NARMAX predictions for the days shown.
Mentions: Figure 4 shows GOES-13 fluxes for the > 800 keV channel compared with fluxes predicted by VNC. Differential fluxes were obtained for two energies—891 keV and 1 MeV—and used to calculate > 800 keV integral fluxes assuming exponential energy distributions. It can be seen that, absent some underestimations at periods of rapid flux decrease, the model follows the data reasonably well. The same analysis was performed on the 1–23 September 2013 time interval, with the results visible on Figure 5. As noted above, the sinusoidal flux variation is a diurnal effect due to the spacecraft traversing different L* regions at different magnetic local times. Black crosses on the Figures 4 and 5 show NARMAX predictions for those time periods. It can be seen that NARMAX predicts variations quite well at geostationary orbit and can be successfully used for outer boundary information as an input to the VERB system.

Bottom Line: The coupled system has been tested for three extended time periods totalling several weeks of observations.The model has successfully simulated energetic electron fluxes for various magnetospheric conditions.Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Automatic Control and Systems Engineering, University of Sheffield Sheffield, UK.

ABSTRACT

This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes for various magnetospheric conditions. Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed.

No MeSH data available.