Coupling between mesosphere and ionosphere over Beijing through semidiurnal tides during the 2009 sudden stratospheric warming

Abstract

Sudden stratospheric warming (SSW) in the winter of 2008/2009 is the strongest recorded SSW event. The enhancement in semidiurnal variation of ionospheric TEC (total electron content) with phase shift forward is shown during 22 to 27 January 2009, based on the TEC observations in Beijing (40.30°N, 116.19°E geographic, 39.73°N dip latitude). We focus on finding the reason for the TEC variation. Winds observed by an all‐sky meteor radar in the same observatory are used to study mesospheric variation. The semidiurnal solar tide in the mesosphere starts to increase before the SSW and maintains oscillation with period 16–20 days during the SSW. The semidiurnal lunar tides in TEC and wind start to increase on 17 and 15 January, respectively. Although the semidiurnal lunar tide in TEC over Beijing almost dies out on 1 February, that over equatorial ionospheric anomaly crest does not vanish until 15 February when lunar tide in wind tends to be very weak. The maximum of lunar tide in wind appears on 2 February at 96 km with amplitudes of 15 m/s and 21 m/s for zonal and meridional winds. The phase comparison shows that lunar tides in TEC and zonal wind reach their maxima at almost the same time, which is 2–4 h lag behind the meridional wind. The coupling between the mesosphere and ionosphere contributes to the semidiurnal variation of TEC through both solar and semidiurnal lunar tides. The enhancement in semidiurnal lunar tide is responsible for the TEC peak shift forward during the SSW.

The Comparison of Lunar Tidal Characteristics in the Low‐Latitudinal Ionosphere Between East Asian and American Sectors During Stratospheric Sudden Warming Events: 2009–2018

“…It provides global TEC maps with spatial and temporal resolutions of 1°× 1°× 5 min, which were calculated from RINEX data of global ground-based GPS receivers (Rideout & Coster, 2006). Those periods are chosen since they represent solar diurnal, semidiurnal, terdiurnal, and lunar semidiurnal tides, respectively, which are suggested to be most dominant in all tidal components during SSW events by some studies (Fejer et al, 2010;Fuller-Rowell et al, 2011;Pedatella & Forbes, 2010;Xiong et al, 2013). Then, the longitude and universal time are converted to local time with lt = ut+longitude/15.…”

“…The amplitudes of each tidal component can be calculated with A n ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi a 2 n þ b 2 n q . The length of data should be at least 14.78 days to separate the solar and lunar semidiurnal tides since 12 and 12.42 hr are so close, and it cannot be too long since the extracted tidal amplitudes may reduce (Xiong et al, 2013). The length of data should be at least 14.78 days to separate the solar and lunar semidiurnal tides since 12 and 12.42 hr are so close, and it cannot be too long since the extracted tidal amplitudes may reduce (Xiong et al, 2013).…”

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

“…The equatorial electroject (EEJ) strength presents significant changes during SSW events [Upadhayaya and Mahajan, 2013]. In addition, the semidiurnal lunar tides in TEC and wind increase during the SSW event [Xiong et al, 2013]. Fejer et al [2010Fejer et al [ , 2011 showed that lunar semidiurnal tidal wave changes are the most likely source of the unusual ionospheric perturbations.…”

“…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.…”

Ionospheric response to 2009 sudden stratospheric warming in the Northern Hemisphere

“…The main finding from their study is that the electron density variation is caused by an enhanced semidiurnal migrating tide (SW2) in the lower thermosphere, although the mechanism of the enhanced SW2 mode is still not understood well. Most recently, Xiong et al [] studied local time variation over Beijing (40.30°N, 116.19°E). They suggested a clear shift of TEC maximum during 22 January to 27 January 2009, as due to the enhanced semidiurnal tide.…”