Impact of sudden stratospheric warmings on equatorial ionization anomaly

Abstract

[1] We investigate the ionospheric response to several stratospheric sudden warming events which occurred in Northern Hemisphere winters of 2008 and 2009 during solar minimum conditions. We use GPS total electron content data in a broad latitudinal region at ±40°geographic latitude and a single longitude, 75°W. In all cases, we find a strong daytime ionospheric response to stratospheric sudden warmings. This response is characterized by a semidiurnal character, large amplitude, and persistence of perturbations for up to 3 weeks after the peak in high-latitude stratospheric temperatures. The ionospheric perturbations at the lower latitudes usually begin a few days after the peak in stratospheric temperature and are observed as an enhancement of the equatorial ionization anomaly (EIA) in the morning sector and a suppression of the EIA in the afternoon sector. There is also evidence of a secondary enhancement in the postsunset hours. Once observed in the low latitudes, the phase of semidiurnal perturbations progressively shifts to later local times in subsequent days. This progressive shift occurs at a different rate for different stratospheric warming events. The large magnitude and persistence of ionospheric perturbations, together with the predictability of stratospheric sudden warmings several days in advance, present an opportunity to investigate these phenomena in a systematic manner which may eventually lead to a multiday forecast of low-latitude ionosphere conditions.

Ionospheric response to the 2009 sudden stratospheric warming over the equatorial, low, and middle latitudes in the South American sector

“…A similar result was reported by Goncharenko et al [2010aGoncharenko et al [ , 2010b, who noticed that the low-latitude ionosphere perturbation persisted for several days after the SSW peak. Further, a time shift has also been observed in the day maximum behavior after the stratospheric temperature peak.…”

“…Earlier studies have demonstrated that the largest variations in VTEC during SSW are observed at the crests of the EIA [Goncharenko et al, 2010a;Liu et al, 2011], and the location of the crests can vary periodically by several degrees in latitude [Mo et al, 2014]. In addition, the difference from one station to another is related with superimposed perturbation caused by MSTID and/or PW disturbances.…”

“…In addition, Goncharenko et al [2010a] recently reported that after the peak in stratospheric temperature, an enhancement of the EIA in the morning sector and a suppression of the EIA in the afternoon sector are observed. Also, Liu et al [2011] showed that at the equatorial region, in the Asian sector, an overall drop of the TECu throughout the daytime occurs during the whole period from DOY 23 to DOY 31, with maximum depletion from DOY 26 to DOY 27, and, at low latitude, the TECu shows a morning enhancement and afternoon depletion in comparison to the quiet time.…”

“…As a result of this change in its interaction, the polar stratospheric temperature increases during several days. Recently, an unforeseen coupling between high latitudes, midlatitudes, and equatorial/low latitudes at upper atmospheric/ionospheric altitudes was discovered during sudden stratospheric warming (SSW) events [Goncharenko and Zhang, 2008;Goncharenko et al, 2010aGoncharenko et al, , 2010bGoncharenko et al, , 2013aGoncharenko et al, , 2013bVineeth et al, 2009;Chau et al, 2010Chau et al, , 2012Liu et al, 2011;Pancheva and Mukhtarov, 2011;Bessarab et al, 2012;Fang et al, 2012;Korenkov et al, 2012;Sripathi and Bhattacharyya, 2012;Sumod et al, 2012;Olson et al, 2013;Upadhayaya and Mahajan, 2013;Xiong et al, 2013;Pedatella et al, 2014aPedatella et al, , 2014b. Therefore, various aspects involved behind the effects of SSW need to be explored in order to improve our knowledge about the Earth's atmosphere.…”

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

“…The modulation of the equatorial plasma fountain has been observed in measurements of the F-region equatorial E × B drift (e.g., Chau et al 2009;Fejer et al 2011). Also, the impact on the equatorial anomaly has been revealed by ground-based and satellite measurements of the F-region plasma density (e.g., Goncharenko et al 2010aGoncharenko et al , 2010bYue et al 2010;Pancheva and Mukhtarov 2011;Lin et al 2012). Figure 48 schematically illustrates the vertical coupling of the atmosphere during stratospheric sudden warmings.…”