On the signature of the quasi‐3‐day wave in the thermosphere during the January 2010 URSI World Day Campaign

Abstract

[1] Ultra-fast Kelvin waves with periods of 3-5 days are important in the coupling of the lower atmosphere to the thermosphere and ionosphere. Here we focus on the observations and effects of a 3-day wave during January 2010. As this time period coincides with a stratospheric warming event, a coordinated set of observations with incoherent scatter radars are available. While there is no evidence that the occurrence of this 3-day wave is connected with this event, these observations offer an unprecedented glimpse of the thermospheric conditions during this period, including the first-ever detection of a 3-day wave with an incoherent scatter radar. Using a combination of ground-and space-based observations, we identify an eastward moving zonal wave number-one 3-day equatorial wave that is comprised of a Kelvin wave at the lowest latitudes and a Rossby-gravity wave at higher latitudes. In the equatorial region, the vertical wavelength is $40 km and the wave peaks in amplitude around 95-100 km altitude. The wave observed here is only seen to propagate to around 105 km altitude. Evidence of an interaction between this wave and the diurnal tide is seen between 82-88 km. The resultant 3-day periodicity in the diurnal tide is seen to propagate up to altitudes of $150 km. This could have a significant impact on the ionosphere via modulation of the E-region dynamo, thus carrying the 3-day periodicity to higher altitudes.

Ultrafast Kelvin waves in the MLT airglow and wind, and their interaction with the atmospheric tides

“…This is because it is well established from ground-based and satellite-borne measurements and modeling studies that the atmospheric tides strongly affect the MLT equatorial airglow and exhibit pronounced nocturnal variation (e.g., Shepherd et al, 1995;Yee et al, 1997;Takahashi et al, 1998). In addition, the tides can interact with other waves (e.g., Teitelbaum and Vial, 1991;Pancheva, 2001;England et al, 2012;Alves et al, 2013), leading to changes in their amplitudes and phases, which in turn could affect the airglow emissions. As there was a 1-day gap on 4 March in the airglow data, we take for this particular analysis the data from 5 to 14 March, which present excellent quality and continuity, and are still long enough to allow the study of the 3-4-day oscillations.…”

“…As well as this, the amplitude of the tides are modulated in the periods of the planetary waves. Previous investigations of England et al (2012) using meteor radar, incoherent scatter radar and satellite wind data, along with satellite-borne temperature data, reported the evidence of the nonlinear interaction between the UFKW and the diurnal tide in the MLT and its effects in the E-region of the ionosphere. To investigate a possible interaction between the UFKW and atmospheric tides, we analyzed the amplitudes of the diurnal tide in the zonal and meridional wind during the presence of the 3-4-day UFKW in March.…”

“…Experimental measurements and numerical modeling have shown the influence of the UFKW in the day-to-day variability of the equatorial ionosphere England et al, 2012;Onohara et al, 2013). One possible way for the planetary-scale waves to communicate their signatures to the ionosphere is through modulations of the atmospheric tides, which are able to penetrate into the ionosphere.…”

“…Most of these studies address the nonlinear interaction between tides and the 2-day, 5-day and 16-day planetary waves. Concerning the UFKW, England et al (2012) investigated the nonlinear interaction between them and the tides in the MLT and its effects in the ionosphere. Their find- ings show that the nonlinear interaction of the UFKW with the diurnal tide is seen between 82 and 88 km, and a resultant 3-day periodicity in the diurnal tide is seen to propagate up to altitudes of approximately 150 km.…”

The ultra-fast Kelvin waves in the equatorial ionosphere: observations and modeling

“…Although this study considers only the superposition of the UFK to the tidal waves at 120 km altitude the nonlinear interaction could still occur through the electrodynamical processes. England et al (2012) reported evidence of a nonlinear interaction between the UFK wave and the diurnal tides using the ground-based meteor radar at Thumba (8.5 • N, 77 • E) and the incoherent scatter radar at Arecibo (18 • N, 66 • W). The nonlinear interaction appeared to happen in altitudes from 82 to 88 km.…”