Multi-instrument observations of large-scale atmospheric gravity waves/traveling ionospheric disturbances associated with enhanced auroral activity over Svalbard

Abstract

This study reports on observations of atmospheric gravity waves/traveling ionospheric disturbances (AGWs/TIDs) using Global Positioning System (GPS) total electron content (TEC) and Fabry-Perot Interferometer's (FPI) intensity of oxygen red line emission at 630 nm measurements over Svalbard on the night of 6 January 2014. TEC TIDs have primary periods ranging between 29 and 65 minutes and propagate at a mean horizontal velocity of ∼749-761 m/s with azimuth of ∼345 •-347 • (which corresponds to poleward propagation direction). On the other hand, FPI AGWs have much larger periods of ∼128-174 minutes (i.e 2.1-2.9 hours). These large-scale AGWs/TIDs were linked to enhanced auroral activity identified from co-located all-sky camera and IMAGE magnetometers. Similar periods, speed and poleward propagation were found for all-sky camera (∼41-49 minutes, ∼823 m/s) and IMAGE magnetometers (∼32-53 minutes and ∼708 m/s). Joule heating as a result of particle precipitation was identified as a likely generation mechanism for these disturbances.

Equatorward Medium to Large‐Scale Traveling Ionospheric Disturbances of High Latitude Origin During Quiet Conditions

“…The horizontal wavelengths values for these TIDs in Figures 4a and 4d are 1,104 km and 737 km, respectively. Based on these characteristics, these structures can be classified as medium to large‐scale TIDs (Hocke & Schlegel, 1996; Hunsucker, 1982; Katamzi‐Joseph et al., 2019).…”

“…Generally, equatorward large‐scale TIDs are linked to auroral region Joule heating, particle precipitation and Lorentz‐coupling processes during geomagnetically disturbed conditions (Balthazor & Moffett, 1997; Borries et al., 2016; Davis, 1971; Hines, 1960; Hunsucker, 1982; Hocke & Schlegel, 1996; Katamzi‐Joseph et al., 2019; Lei et al., 2008, and references therein). It is now well established from a variety of studies that fluctuations in energy within the auroral regions caused by geomagnetic storm related processes, significantly influence thermospheric composition, through contributing to equatorward large‐scale TIDs (Balthazor & Moffett, 1997; Hocke & Schlegel, 1996; Hunsucker, 1982, and references therein).…”

“…For decades, traveling ionospheric disturbances (TIDs) have been studied (e.g., Balthazor & Moffett, 1997; Hines, 1960; Hocke & Schlegel, 1996; Hunsucker, 1982; Jing & Hunsucker, 1993; Katamzi‐Joseph et al., 2019; Ngwira et al., 2012; Richmond, 1978, and references therein). It is generally believed that TIDs are signatures in the ionosphere of atmospheric gravity waves (AGWs).…”

“…It is generally believed that TIDs are signatures in the ionosphere of atmospheric gravity waves (AGWs). TIDs are wave‐like perturbations in the ionospheric parameters, such as plasma density, ion and electron temperature and wind (Hocke & Schlegel, 1996; Katamzi‐Joseph et al., 2019; Nicolls et al., 2014). The underlying neutral AGWs perturbations can be generated in the lower, middle and upper atmosphere by various processes (Balachandran, 1980; Chan & Villard, 1962; Fovell et al., 1992; Hocke & Schlegel, 1996; Katamzi‐Joseph et al., 2019; Nastrom & Fritts, 1992; Pradipta et al., 2016; Vadas et al., 2018).…”

“…Large‐scale TIDs have periods that range between 30 min and 3 hr, horizontal phase speeds greater than 250 m/s, wavelength of more than 1000 km, and generally propagate equatorward from both hemispheres (Hocke & Schlegel, 1996; Katamzi‐Joseph et al., 2019). Medium‐scale TIDs have horizontal propagation velocities of 100–250 m/s, period of 15–60 min and wavelengths of approximately 100–1,000 km, and can propagate in any direction (Hocke & Schlegel, 1996; Katamzi‐Joseph et al., 2019; Kotake et al., 2007; Mayr et al., 1984; Vadas & Becker, 2019). It is known that AGWs play an important role in the transportation of energy and momentum (vertically and horizontally) in the different layers of the atmosphere, which can affect satellite‐based navigation systems (Datta‐Barua et al., 2010).…”