Multi-Resolution Assimilative Analysis of High-Latitude Ionospheric Convection in both Hemispheres

Tuesday, 16 December 2014
Zachary Micah Thomas, Ohio State University Main Campus, Columbus, OH, United States, Tomoko Matsuo, University of Colorado, Boulder, CO, United States, Douglas W Nychka, NCAR, Boulder, CO, United States, Ellen D. P. Cousins, National Center for Atmospheric Research, Boulder, CO, United States and Michael James Wiltberger, National Center for Atmospheric Research, High Altitude Observatory, Boulder, CO, United States
Assimilative techniques for obtaining complete maps of ionospheric electric potential (and related parameters) from sparse radar and satellite observations greatly facilitates studies of magnetosphere/ionosphere coupling. While there is much scientific interest in studying interhemispheric asymmetry in ionospheric convection at both large and small scales, current mapping procedures rely on spherical harmonic expansion techniques, which produce inherently large-scale analyses. Due to the global nature of the spherical harmonics, such techniques are also subject to various instabilities arising from sparsity/error in the observations which can introduce non-physical patterns in the inferred convection. We present a novel technique for spatial mapping of ionospheric electric potential via a multi-resolution basis function expansion procedure, making use of compactly supported radial basis functions which are flexibly located over geodesic grids; the coefficients are modeled via a Markov random field construction. The technique is applied to radar observations from the Super Dual Auroral Radar Network (SuperDARN), whereupon careful comparison of interhemispheric differences in mapped potential is made at various scales.