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Dominant spatial and temporal patterns of horizontal ionospheric plasma velocity variation covering the northern polar region, for the period 1997.0 to 2009.0
GB/NERC/BAS/PDC/01159

Summary

Abstract:
We present a reanalysis of SuperDARN plasma velocity measurements, using the method of data-interpolating Empirical Orthogonal Functions (EOFs). The northern polar region's radar-measured line of sight Doppler velocities are binned in an equal-area grid (areas of approximately 110,000km2) in quasi-dipole latitude and quasi-dipole magnetic local time (MLT). Within this spatial grid, which extends to 30 degrees colatitude, the plasma velocity is given in terms of cardinal north and east vector components (in the quasi-dipole coordinate frame), with the median of every SuperDARN measurement in the spatial bin taken every 5 minutes. These sparse binned data are infilled to provide a measurement at every spatial and temporal location via EOF analysis, ultimately comprising a series of monthly reanalyses, from 1997.0 to 2009.0. This resource provides a convenient method of using SuperDARN data without its usual extreme sparseness, for studies of ionospheric electrodynamics during solar cycle 23. The reanalyses are provided in monthly sets of orthogonal modes of variability (spatial and temporal patterns), along with the timestamps of each epoch, and the spatial coordinate information of all bin locations. We also provide the temporal mean of the data in each spatial bin, which is removed prior to the EOF analysis.

Funding was provided by the NERC grant NE/N01099X/1.

Keywords:
Data Interpolating Empirical Orthogonal Functions, Ionosphere electrodynamics, Plasma velocity, Polar electric field, SuperDARN reanalysis

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