EARTH SCIENCE > Sun-earth Interactions > Ionosphere/Magnetosphere Dynamics > Electric Fields/Electric Currents
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Signals from manmade VLF transmitters, used for communications with submarines, can leak into space and contribute to the dynamics of energetic electrons in the inner radiation belt and slot region. We use ~5 years of plasma wave data from the Van Allen Probe A satellite to construct new models of the observed wave power from VLF transmitters both as a function of L* and MLT and geographic location. This work is reported in Meredith et al. (2019) and the data provided here enable reconstruction of all of the figures in the paper.
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. ***** PLEASE BE ADVISED TO USE VERSION 2.0 DATA ***** This version (1.0) has an error in radar data processing that the new version corrects. This is available via the ''Related Data Set Metadata'' link below
The data set comprises of ionospheric vorticity estimates determined from measurements of ionospheric velocity made by the Super Dual Auroral Radar Network (SuperDARN). The vorticity estimates have been determined across the whole of the northern hemisphere polar ionosphere. The data cover the interval from 2000 to 2005 inclusive.
The data set comprises ionospheric vorticity estimates determined from measurements of ionospheric velocity made by overlapping pairs of northern hemisphere radars in the Super Dual Auroral Radar Network (SuperDARN). The vorticity estimates are separated into data files for each pair of SuperDARN radars that contributed to the whole data set. These data cover large regions of the northern hemisphere polar ionosphere, and the locations of the vorticity estimates are presented in both geographic and Altitude-Adjusted Corrected GeoMagnetic (AACGM) co-ordinates. The data cover the interval from 2000 to 2005 inclusive. This work was funded by NERC grant reference NE/R016038/1.
A forecast model of the northern high-latitude ionospheric plasma motion as observed by the SuperDARN radars. The model comprises a set of regression coefficients. The user needs to specify the day-of-year and the monthly mean of the solar radio flux at 10.7 cm/2800 MHz, often called the f10.7 index. They also need to provide the value of the interplanetary magnetic field (IMF) component By and the Sun-Earth component of the solar wind velocity Vx, both in geocentric solar magnetospheric (GSM) coordinates. The regression coefficients are provided as two files, one can be used to model the north-south (NS) component of the plasma motion and the other to model the east-west (EW) component of the motion. Funding was provided by NERC standard grant numbers: NE/V002732/1, NE/N01099X/1, NE/V00283X/1, NE/V002686/1 and NE/T000937/1.
Instrumentation was deployed in the Antarctic Peninsula region to monitor conditions occurring in the region of near-space surrounding the Earth. The opportunity was taken to link into a NASA satellite mission occurring at the same time and with similar goals - to study the dynamics of the Earth-Sun system at a location where the two systems are finely balanced. The experiments have been used to interpret the changes in plasma composition at the same point in space due to solar weather events. A refurbished VLF Doppler receiver was installed at Rothera to measure plasmaspheric electron concentration. The electron number density was determined from analysis of the 15 minute integration providing group delay times, Doppler shift and arrival bearing of whistler-mode signals, of man-made transmissions, from MSK format transmitters from north east America. If you would like more information about the VLF Doppler receiver data that is still being routinely collected at Rothera please contact the UK Polar Data Centre at the British Antarctic Survey.