Authors: S.D. Bouwer, W.K. Tobiska; A. Komjathy, B. Wilson, X. Pi, A. Mannucci
Affiliation: Space Environment Technologies; NASA Jet Propulsion Laboratory
The “2003 Halloween" solar-terrestrial events are significant not only for their dramatic scale, but for their unique phasing of solar irradiance and geomagnetic events. During Oct 28, 2003 geomagnetic activity was relatively normal, while solar irradiances in X-ray and EUV were exceptionally high. Conversely, Oct 29-31 was geomagnetically active while solar X-ray was relatively low. These sequence of events can be used to evaluate potential effects in ionospheric and thermospheric densities. While the flares and CMEs were unpredictable, the active regions from which they evolved were longer lived. We present the evolution of the irradiances from these active regions, our forecasts of their probable evolution compared with actual events, and a visualization of both irradiance and geomagnetic effects upon the terrestrial ionosphere. The solar irradiances are produced by SOLAR2000 v2.23, which are tied to the absolute values of the TIMED/SEE preliminary v7 data. We also show a comparison of these irradiances in the E1_40 parameter, i.e., the integrated EUV energy flux between 1-40 nm, compared to the TIMED/GUVI derived irradiances for a period of active region solar rotation in 2002. Furthermore, we take advantage of the network of some 400 Continuously Operating Reference Sites' (CORS) dual-frequency GPS receivers within the Unites States to estimate the Total Electron Content (TEC) of the ionosphere. We demonstrate the dramatic impact of the solar X-ray/EUV and the disturbed geomagnetic field on the earth's ionosphere in the mid-latitude region.