Correlation between the global occurrences of ionospheric irregularities and deep atmospheric convective clouds in the intertropical convergence zone (ITCZ)

Abstract

To study the seeding mechanism of ionospheric irregularity occurrences, a correlation study has been carried out between the global monthly/latitudinal (m/l) distributions of irregularity occurrences and the deep atmospheric convective clouds in the intertropical convergence zone (ITCZ) indicated by the outgoing longwave radiation (OLR) measurements. Seven longitude sectors -the African, Indian, West Pacific, Central Pacific, East Pacific, South American, and Atlantic sectors -are selected to study the correlations between the two distributions. The results indicate that good correlations exist only in the South American sector and to some extent in the African sector. For the other five sectors, no correlations are found in the m/l distributions between the irregularities and OLRs. This implies that the gravity wave induced in the ITCZ cannot be the sole seeding agent for the Rayleigh-Taylor (RT) instability in the global irregularity occurrences every season. We suspect that the post-sunset ionospheric electrodynamic perturbations could be the prevailing seeds for the RT instability globally year long. Together with the favorable post-sunset ionospheric condition, the global m/l distributions of irregularity occurrences could be adequately explained.

Enhanced ionospheric plasma bubble generation in more active ITCZ

“…In earlier studies on the statistical correlation between ionospheric bubbles and ITCZ, the daily OLR values were used [e.g., McClure et al , ; Tsunoda , ; Su et al , ]. Here we adopt a similar way as that used in the earlier studies to investigate if there is any relationship between the significantly enhanced bubble generation over Kototabang and the ITCZ.…”

“…Figure 4 (right bottom) shows the longitudinal variation of the mean occurrence rate of OLR within ±5°magnetic latitude. Note that the OLR (<190) occurrence rate is also shown since Su et al [2014] suggested that a well-defined threshold of OLR (with lower values) would help to assure the GW occurrence. It is evident from the panel that for both thresholds (190 and 205), the OLR occurrence rate is clearly higher at Kototabang longitude than at Sanya longitude.…”

“…He suggested that GWs generated in ITCZ could play an important role in the development of bubbles during solstice. However, a more recent work by Su et al [] showed that the relationship was not seen except at South American and African longitudes.…”

Analysis of temporal–longitudinal–latitudinal characteristics in the global ionosphere based on tensor rank-1 decomposition

“…Although many research studies on the ionosphere have been conducted based on geographic coordinates (Su et al 2014;Talaat and Zhu 2016), some ionospheric characteristics, especially north-south asymmetry, are also investigated compared with geomagnetic coordinates (Geonhwa et al 2004(Geonhwa et al , 2005Weihua and Jiaping 2015). Many geospace phenomena, including ionospheric currents, are highly organized by the Earth's main geomagnetic field.…”

An Investigation into Height Variation of Ionospheric Signature Due To the Cyclonic Storm Formation Using COSMIC-RO Measurements

“…As early as in 1950s, Bauer (1958), for the first time, observed ionospheric signature in the passage of hurricanes and found that maximum enhancement in foF2 occurred when hurricanes were closest to the observation station. Also, Huang et al (1985) In fact, most of the previous studies have been reported about two responsible mechanisms which affect the ionosphere mostly during different lower atmospheric meteorological phenomena, these are: (i) Electrical and Electromagnetic process (Harrison et al 2010, Sorokin et al 2005, and (ii) Upward propagating waves generated in the neutral atmosphere (Lastovicka, 2006;Su et al 2014), such as the planetary waves, the tidal waves and the AGWs (Killeen and Johnsson, 1995;Bhattacharya and Das, 2013). However, the former option is out of the scope of this study and ionospheric signature due to the evolution in AGWs is of our main concern.…”