CEDAR: Whole-Atmosphere Modeling of Ionospheric Responses to Atmospheric Variability

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The scientific objective of this investigation is to evaluate the contribution of lower atmospheric dynamics to the variability of ionospheric electrodynamics and electron densities. The investigation addresses the two scientific questions:1. How well can winds generated internally in a whole-atmosphere model explain observed quiet-day ionospheric electric fields and currents? What information can model-observation discrepancies give us about atmospheric processes? 2. How much of the observed quiet-day variability of ionospheric electric fields, currents, and electron densities can be attributed to variable winds from the lower atmosphere?The Whole Atmosphere Community Climate Model (WACCM), a numerical simulation model of atmospheric dynamics, chemistry, energetics, and electrodynamics from the ground to about 500 km altitude, will be upgraded to simulate ionospheric dynamics and electrodynamics realistically, and to calculate geomagnetic perturbations produced by ionospheric electric currents. Comparisons between simulated and observed ionospheric electric fields and electron densities, as well as geomagnetic perturbations on the ground and at low-Earth-orbit satellite altitudes, will indicate how well WACCM can simulate winds in the ionospheric dynamo region. Additional simulations using adjustments to uncertain WACCM parameterizations, to achieve improved model-data agreement, will provide information about the parameterized processes, especially the effects of momentum transport by gravity waves. The WACCM results will then be analyzed to evaluate the variability of electric fields, currents, and ionospheric densities associated with variability in atmospheric tides and planetary waves produced in the lower and middle atmosphere. This variability will be assessed in relation to that caused by magnetospheric electrodynamic effects on the ionosphere, through additional simulations that vary the magnetospheric electric potential imposed at high latitudes. The investigation will contribute to the development of WACCM, a community model for exploring and understanding effects of coupling between the lower and upper atmosphere. The WACCM documentation will be expanded to include the new model developments, and the enhanced version of WACCM will be made available to the scientific community for use in other studies. The developments of WACCM components in this investigation will also be used to improve other upper-atmosphere models on which the research team are collaborating.