A multi-diagnostic approach to understanding high-latitude plasma transport during the Halloween 2003 storm

Abstract

Abstract. During the Halloween 2003 storm event, significant electron density enhancements at elevated F-layer altitudes were recorded by the EISCAT and ESR radars in northern Europe between 20:00 and 24:00 UT on 30 October. At the same time, a sequence of optical images from Qaanaaq in northern Greenland captured a series of eastward-propagating polar cap patches. In this paper, an advanced 4-D tomographic method based on the assimilation of global GPS data, coupled to a predictive Kalman filtering technique, has been used to reveal the linkage between these ionospheric structures. The combination of the various data sources has clearly established the time history of this extreme event, in which high-density plasma was uplifted in the dayside ionosphere and convected anti-sunward across the polar cap to European high latitudes at an elevated F-layer. Using this multi instrument approach, we can differentiate between those density structures observed at the ESR which occurred as a result of cross-polar transport and those more likely to have been produced by in-situ soft particle precipitation, a distinction which is supported by the ESR and EISCAT data. The multi-diagnostic approach reported here has the potential significantly to extend our current understanding of high latitude plasma transport and the origin of electron density enhancements.

Automated identification and tracking of polar-cap plasma patches at solar minimum

“…Since the geometry of the problem and the limitations of data collection ensure that the problem is under-determined, additional constraints are required in order to obtain a unique solution in any given circumstance (Austen et al, 1988). The extant MI-DAS literature shows that the algorithm is capable of identifying structures of approximately 500 km and greater in scale including plasma patches (Burston, 2012;Yin and Mitchell, 2011;Yin et al, 2008Yin et al, , 2009). …”

Global Ionospheric Processes

“…A comparison of TEC measurements from an individual receiver in Thule and optical intensities from Qaanaaq showed the large-scale features to correspond qualitatively between the two data types, but the amplitudes of the density fluctuations were not linear, and the high degree of structure seen in the optical emissions was not fully captured in the TEC tomographic reconstructions. This work has now been published by Yin et al [2008].…”

Comparison of temporal fluctuations in the total electron content estimates from EISCAT and GPS along the same line of sight

“…A further complication is introduced by the conversion of TEC measurements corresponding to slant ray path into values corresponding to vertical ray paths, in order to increase the map coverage (Meggs et al, 2004). Calibrated TEC measurements are also used in tomographic imaging of the upper ionised atmosphere (Bust and Mitchell, 2008;Yin et al, 2008;Yizengaw et al, 2006a, b). Similarly to the approach used in the case of maps, tomographic images rely on calibrated slant TEC measurements, which are then used to reconstruct 2-D or 3-D images by assuming a theoretical model for the electron density vertical profile (Bust and Mitchell, 2008, and references therein).…”