Multi-Scale Geomagnetic Forcing Derived From High-Resolution Observations and Their Impacts on the Upper Atmosphere

Techniques developed in the past few years enable the derivation of high-resolution regional ion convection and particle precipitation patterns from the Super Dual Auroral Radar Network (SuperDARN) and Time History of Events and Macroscale Interactions during Substorms All-Sky Imager (ASI) observations, respectively. For the first time in this study, a global ionosphere-thermosphere model (GITM) is driven by such high-resolution patterns to simulate the I-T response to the multi-scale geomagnetic forcing during a real event. Specifically, GITM simulations have been conducted for the 26 March 2014 event with different ways to specify the high-latitude forcing, including empirical models, high-resolution SuperDARN convection patterns, and high-resolution ASI particle precipitation maps. Multi-scale ion convection forcing estimated from high-resolution SuperDARN observations is found to have a very strong meso-scale component. Multi-scale convection forcing increases the regional Joule heating (integrated over the high-resolution SuperDARN observation domain) by ∼30% on average, which is mostly contributed by the meso-scale component. Meso-scale electron precipitation derived from ASI measurements contributes on average about 30% to the total electron energy flux, and its impact on the I-T system is comparable to the meso-scale convection forcing estimated from SuperDARN observations. Both meso-scale convection and precipitation forcing are found to enhance ionospheric and thermospheric disturbances with prominent structures and magnitudes of a few tens of meters per second in the horizontal neutral winds at 270 km and a few percent in the neutral density at 400 km through comparisons between simulations driven by the original and smoothed high-resolution forcing patterns.