Sensitivity of IFM/GAIM-GM Model to High-Cadence Kp and F10.7 Input

Abstract:

The GAIM‑GM model assimilates observed ionospheric data and ingests it into the IFM background ionosphere, which is highly dependent on K_p and F_10.7. The Air Force Weather Agency typically uses a daily K_p and F_10.7 when running the IFM. This study used K_p and F_10.7 values at 1‑hourly, 3‑hourly, and daily cadence intervals in the IFM and the resulting GAIM‑GM model total electron content (TEC) output was verified using skill scores. This study showed that while the IFM produced different output for different cadence configurations, the GAIM‑GM model output showed little or no variation. It also showed that when ingested data was suddenly removed from the GAIM-GM model, skill scores decayed to those of the model’s background ionosphere at the same rate, regardless of cadence configuration. In addition, alternate sources of K_p and F_10.7 data were investigated, to include data from the ACE satellite as an alternate to K_p, and F_11.1 data as an alternate to F_10.7. While the use of ACE K_p data had little effect on GAIM‑GM model output, the use of F_11.1 data showed improvement in three of the five periods tested, with a reduction in root mean square error of up to 1.17 TEC units.