Post-processing and visualization of ISR data

by Juan Araújo, Department of Science and Mathematics Education, Umeå University

Incoherent scatter radar (ISR) techniques provide reliable measurements for
the analysis of ionospheric plasma. Measurements of electron and ion densities,
temperatures, and line-of-sight velocities are derived by employing antennas
that transmit and receive radio waves. Recent developments in ISR technologies
are capable of generating high-resolution volumetric data from multiple beam
measurements. Examples of such technologies employ the so-called phased array
antennas like the AMISR in North America or the upcoming EISCAT_3D in the
northern Fennoscandia region. Traditional visualization methods, for example,
2D projections, applied to volumetric images render a reduced set of the
available data and important aspects of the data may be lost to the analyst.
     
We present an interactive approach for the exploration and visualization of
spatio-temporal and volumetric ionospheric data. The strategy is targeted at
offering the analyst a wider range of alternatives in order to interpret ISR
data. The proposed novel strategy allows for the reconstruction of ionospheric
volume images by means of a novel sparse interpolation algorithm tailored for
the particular features of ISR data. The interpolation offers estimation of
gradients and processing of the challenging case of missing data. The
reconstructed image is output by using volume rendering combined with
customizable transfer functions. We propose to utilize reconstructed volumetric
images for the estimation of ionospheric conductivities and volumetric
currents, which in turn can be used for studying the evolution of storms and
substorms in the ionosphere.