DOI: 10.26050/wdcc/othitacs_tiegcm
title: The open time-series of the high-resolution ionosphere-thermosphere aeronomic climate simulation (OTHITACS)

description: Project: The open time-series of the high-resolution ionosphere-thermosphere aeronomic climate simulation - The OTHITACS project aims to provide a continuous high-resolution simulation of the Earth's ionosphere and thermosphere from 1 January 2000. The ionosphere and thermosphere are important regions of our near-Earth space environment. A better understanding of these regions is useful not only for socio-economic reasons, including the management of space assets, but also for other far-reaching consequences of space weather. In the experiment, "the physics-based TIE-GCM OTHITACS", we run the thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM; http://www.hao.ucar.edu/modeling/tgcm) at high resolution using the computing and data resources provided by the Kratos HPDA (high-performance data analysis) cluster at the German Aerospace Center (DLR). We provide 38 diagnostics of the ionosphere-thermosphere system at a cadence of 10 minutes. These diagnostics describe the dominant plasma and neutral structures and the electrodynamics of the ionosphere-thermosphere system. We are making this unprecedented data set freely available to the aeronomy community to improve climate studies. Some of the phenomena that could be studied with this data set include ionospheric plasma density variability, neutral composition trends, neutral winds, ion drift velocity, equatorial anomaly, and travelling ionospheric/atmospheric disturbances. Summary: TIE-GCM (thermosphere-ionosphere-electrodynamics general circulation model) is a three-dimensional, time-dependent, physics-based model of the thermosphere and ionosphere (https://doi.org/10.1029/92GL00401). The website http://www.hao.ucar.edu/modeling/tgcm hosts the open-source TIE-GCM code. TIE-GCM assumes hydrostatic equilibrium, constant gravity, steady-state ion and electron energy equations, and incompressibility on a constant pressure surface . In this experiment, we use TIE-GCM version 2.0 (released on 21 March 2016) with a horizontal resolution of 2.5 by 2.5 in geographic latitude and longitude, and a vertical resolution of 0.25 scale-height. We specify the solar irradiance input to the model via an empirical solar proxy model—the extreme ultraviolet flux model for aeronomic calculations (EUVAC; https://doi.org/10.1029/94JA00518; https://doi.org/10.1029/2005JA011160). This empirical formulation uses the average of the daily solar flux F10.7 and its 81-day centred mean. Here, we use the value observed by the ground-based solar radio telescope, as it is more suitable for upper-atmospheric applications than the F10.7 adjusted for Earth-Sun distance. We use the Kp index-based ion convection model of Heelis et al. (1982; https://doi.org/10.1029/JA087iA08p06339) and the auroral particle precipitation scheme of Roble and Ridley (1987; https://ui.adsabs.harvard.edu/abs/1987AnGeo...5..369R) with modifications of Emery et al. (2012; http://doi.org/10.5065/D6N29TXZ) to specify the magnetospheric forcing, which describes the high-latitude mean energy, energy flux and electric potential. To account for the tidal forcing from the lower atmosphere, we use the global scale wave model (GSWM) of Hagan et al. (2001; https://doi.org/10.1029/2000JA000344) to perturb the lower boundary of the TIE-GCM. Here, the GSWM specifies the migrating diurnal and semidiurnal and the nonmigrating diurnal and semidiurnal tides, which add perturbations to the zonal mean neutral temperature and horizontal winds, among others. We also add perturbations to the advective and diffusive transport via the eddy diffusion coefficient described in Qian et al. (2009; https://doi.org/10.1029/2008JA013643).