Ionospheric drift measurements: Skymap points selection

Abstract

[1] In this paper we concentrate on the plasma drift measurement performed by Digisonde Portable Sounder DPS 4 developed by the UMLCAR, Lowell. Special attention is paid to the quality control of data acquired prior to drift velocity calculations. Risks of carefree use of raw Doppler spectra for the plasma motion analysis have been recognized in the Digisonde community. In this paper we propose improvements of Digisonde drift data processing for velocity evaluation and provide a detailed step-by step description: (1) robust height range selection, (2) setting limits on the Doppler frequency shift, and (3) setting limits on the echo arrival angle. Raw data that passed our quality control were then used to derive three velocity components of the bulk plasma drift in the ionosphere. In the paper we discuss, in detail, application of the method on the DPS measurements. However, this technique can be efficiently applied on any other digital ionosondes drift data processing.

Storm time equatorial plasma bubble zonal drift reversal due to disturbance Hall electric field over the Brazilian region

“…[], Kozlov and Paznukhov [], and Kouba et al . [] . The daytime vertical drift calculated from the magnetic field variation (ΔH) at São Luis (2.33°S, 44.6°W; dip angle: −1.6°) and Vassouras (22.4°S, 43.7° W; dip angle: −34°)‐Brazil will also be analyzed.…”

“…This method is implemented by interactive software named Drift Explorer, which allows the determination of the three components of the plasma drift, V N , V E , and V z (north, east, and vertical components). For more details about the drift velocity calculations by the Digisonde, see Reinisch et al [1998], Kozlov and Paznukhov [2008], and Kouba et al [2008]. The daytime vertical drift calculated from the magnetic field variation (ΔH) at São Luis (2.33°S, 44.6°W; dip angle: À1.6°) and Vassouras (22.4°S, 43.7°W; dip angle: À34°)-Brazil will also be analyzed.…”

Ground-based measurements of ionospheric dynamics

“…Selection of points for correct velocity estimates was proposed by Kouba et al (2008). Correct height range should be used for the velocity calculations.…”

“…Digisondes provide real-time drift velocity estimation automatically using all detected reflection points. However, for more precise drift velocity analysis it is necessary to select carefully the reflection points manually (Kouba et al, 2008). The final products of DDM are three drift velocity components, i.e.…”

“…A set of these points can be displayed in the SKYmap. Finally, the unique velocity vector of the ionospheric plasma at selected height range is estimated for detected source points by means of Least-Squares fitting (Kouba et al, 2008).…”