Toward Development of Empirical Conductance Relations using Incoherent Scatter Radar Data

Abstract:

Conductivity enhancements in the E-region ionosphere associated with auroral particle precipitation remains a challenging parameter to specify in space weather models. The best known and most widely used empirical conductance relations were developed by Robinson et al., 1987. Although these simple relations contain some of the essential physical dependencies, these relations were effectively a parameterization of model outputs. While these relations form a useful tool that are easy to calculate, the next generation of empirical conductance relations should be based on data that span the range of possible responses from auroral processes and take into account dependence upon the thermosphere, along with auroral morphology type. Such a relation would be a clear step forward toward a more realistic specification of conductance driven by auroral particle precipitation.

We present first results from the development of an empirical conductance model based on incoherent scatter radar data collected by the Poker Flat Incoherent Scatter Radar (PFISR) near Fairbanks, Alaska, USA. PFISR has been operating nearly continuously since 2007, with at least one radar beam parallel to the local geomagnetic field that measures the altitude resolved electron density, making calculation of the conductivities possible. Given the nearly continuous operations over a solar cycle, the observations span a wide range of variation. We discuss the development of a technique to estimate the energy flux and average energy of the precipitation based on the electron density enhancements in the E-region, but relaxing the assumption on the spectral shape of the electron flux. We present a subset of results from the database of the Hall and Pedersen conductivity associated with discrete, diffuse, and pulsating aurora, along with other parameters such as the average energy, energy flux, geophysical and thermospheric proxies. In some cases, we compare our results with near passes from satellite observations by DMSP.