High-Latitude Joule Heating in TIE-GCM 3.0: Evaluation of Different Plasma Convection Forcing Models

Kurzfassung

We systematically evaluate the high-latitude Joule heating of the recently released version 3.0 Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM) by comparison to EISCAT incoherent scatter radar measurements. The model performance is examined using normalized root mean square deviations derived from test runs driven by different convection patterns from empirical and data-assimilated models. The following features are revealed: (a) Data-assimilated geomagnetic forcing improves the agreement between modeled and EISCAT-derived Joule heating rates by 8%, 28%, and 54% for low, moderate, and high geomagnetic activity. (b) Increasing model grid resolution from 2.5° to 1.25° leads to 20% higher Joule heating rates. (c) AMIE-driven runs better reproduce the magnitude of the Joule heating rates, AMGeO-driven runs the vertical profile. (d) Internal model time step resolution has no effect on the Joule heating rates.