SAMI3 Simulations of Ionospheric Variability from 1996 to 2011

The Naval Research Laboratory is conducting an interdisciplinary physics-based space weather model development and validation program called the Integrated Sun-Earth System for the Operational Environment (ISES-OE). The goal of ISES-OE is to improve our quantitative understanding of the space environment, which can disrupt or degrade operational communications and navigation systems, and ultimately to advance our ability to forecast space weather on multiple time scale, from hours to the 11-year solar cycle. We have performed simulations with SAMI3, NRL's physics-based model of the ionosphere, for the solar and geomagnetic conditions that existed from 2006 and 2011, which includes the past two solar minima. The simulations are driven with a solar irradiance model based on TIMED/SEE measurements and with daily Ap and F10.7 indices. Thermospheric conditions are specified with empirical models of the neutral wind (HWM07) and neutral composition and temperature (NRLMSISE-00). We use a version of NRLMSISE-00 that has been tuned to a global average mass density model derived from orbit data. We compare SAMI3 with various measurements, including global TEC maps, ionosonde-derived NmF2 and hmf2, and GUVI measurements of exospheric temperature. We quantify contributions to global electron content from sources including solar irradiance, geomagnetic conditions, and semi-annual and annual oscillations (SAO and AO) of thermospheric composition, mass density and temperature. We also quantify differences between the 1996 and 2009 solar minima.