HelMod is able to provide a forecast of GCRs intensity. The procedure was presented in Boschini et al 2017. The forcasting is obtained by averaging number of smoothed sunspot number (SSN), tilt angle of neutral sheet, magnetic field at Earth and Solar Wind velocity on previuos solar cycles in which those data are available. The procedure presented followings that from Owens et al 2011, 2012 .
In the above Figure (taken from Boschini et al 2017; Della Torre 2017) is presented an example of HelMod application on past years (blue solid line) compared with measurements from past missions. From 2017, the red line represents the average forecasted differential intensity using historical data up to date. The shaded bands represent the uncertainties, i.e. \(\sim20\%\). It is evaluated considering tha maximum and minimun simulated flux using considering the uncertanties on forecasted solar parameters.
To forecast solar parameters, we consider the previuos solar cycles from which those data are available. In fact, the average variation of the used parameters can obtained along an ideal solar cycle of fixed average duration. In the following figure, it is shown how such a procedure was applied to SSN (e.g., see Della Torre 2017). In the left panel, the historical values of SSN in last 12 cycles are shown. In the upper right panel the average variation of parameters (along an ideal solar cycle of fixed average duration) is shown as a black dashed line and is compared with historical data. In the bottom right panel, it is shown the computed normalization factor (blue dots) appliead to historical SSN data. The normalization factor is used to scale each solar cycle to such an average value. These factors were fitted to sinusoidal curves to estimate the long term modulation of SSN cycles.
The prediction of forthcoming years can be further emproved using the parameters measured in the latest 3 years, thus obtaining an better approximation on short term scale. An example of waht can be obtained using such a procedure is shown in the follow figures regarding the period 2017 to 2021.
The so far described procedure was applied to tilt angle of neutral sheet, magnetic field at Earth and Solar Wind velocity and allowed us to forecasting for the next two solar cycles. such forecasting is available using the online calculators.
This procedure was successfully applied to past missions data and allowed us to estimate that the forecasting accuracy varies from 10% to 40% depending on the solar activity period. Bechnmark on past data show how anomalous period are hard to forecast, but a better training of forecast functions is expected.
Boschini, M.J., Della Torre, S., Gervasi, M., Grandi D., La Vacca, Pensotti S., G., Rancoita, P. G., Rozza D. and Tacconi, M. (2017) The HelMod Monte Carlo Model for the Propagation of Cosmic Rays in Heliosphere Proceedings of the International Astronomical Union, Proceedings of IAU Symposium 335 - Space Weather of the Heliosphere: Processes and Forecasts, July 17-21, 2017, University of Exeter, UK 13(S335):276–279, 2017.
|Della Torre S. HelMod Forecasting of the Intensities of Ion Cosmic Rays, Oral contribution at SPACEMON – Dec 13-15, 2017|
Owens, M. J.; Lockwood, M.; Barnard, L.; Davis, C. J. (2011) Solar cycle 24: Implications for energetic particles and long-term space climate change Geophysical Research Letters, Volume 38, Issue 19, CiteID L19106
|Owens, M. J.; Usoskin, I.; Lockwood, M. (2012) Heliospheric modulation of galactic cosmic rays during grand solar minima: Past and future variations Geophysical Research Letters, Volume 39, Issue 19, CiteID L19102|