On the Relationship Between E Region Scintillation and ENSO Observed by FORMOSAT‐3/COSMIC. Issue 5 (6th May 2018)

• Record Type: Journal Article
• Authors: Chang, Loren C.; Chiu, Pei‐Yun; Salinas, Cornelius Csar Jude H.; Chen, Shih‐Ping; Duann, Yi; Liu, Jann‐Yenq; Lin, Chien‐Hung; Sun, Yan‐Yi
• Is Part Of: Journal of geophysical research. Volume 123:Issue 5(2018)
• Page Start: 4053
• Page End: 4065
• Publication Date: 2018-05-06
• Subjects: sporadic E -- scintillation -- ENSO -- vertical coupling -- GPS RO -- ionosphere; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2018JA025299
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Global Navigation Satellite System radio occultation signals often show extremely strong levels of scintillation when passing through the ionospheric E region. This is related to sporadic E ( E s )—dense layers of metallic ions that can form in the E region, influencing terrestrial and satellite radio propagation. In our report on the 2007–2014 variation of E region S 4 amplitude fluctuation indices measured by the FORMOSAT‐3/Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) satellite constellation, we find that the spatial and temporal variation of the maximum S 4 index in the E region is proportionate to the occurrence rate of extreme scintillation and by extension, sporadic E . We also find that the monthly median extreme S 4 amplitude fluctuation index in the E region midlatitudes shows a dependence on variation of the El Niño–Southern Oscillation (ENSO) in the troposphere that has not been previously reported. The ENSO‐related variation of the E region median extreme S 4 indices varies closely with the tropopause height, with both parameters lagging the Oceanic Niño Index by roughly 1 to 2 months, while also displaying a similar spectrum of periodicities. This similarity is especially strong in the southern midlatitudes. These results indicate that ENSO signatures can be transmitted to E s formation mechanisms, potentially through modulation of vertically propagating atmospheric tides that alter lower thermospheric wind shears. The end result is the modulation of the interannual variation of extreme E s values by ENSO. Plain Language Summary: Global Navigation Satellite System signals often become extremely unstable when passing through altitudes between approximately 90 and 110 km. This is related to dense layers of metallic ions deposited by meteors burning up in the atmosphere, known as sporadic E ( E s ). In our observations of the fluctuation of Global Navigation Satellite System signals passing through this region measured by the FORMOSAT‐3/Constellation Observing System for Meteorology Ionosphere and Climate satellite constellation, we find that the level of signal fluctuation shows a dependence on variation of the El Niño–Southern Oscillation (ENSO) in the troposphere that has not been previously reported. A similar ENSO‐related variation is also observed in the height of the tropopause between 10 and 20 km, showing that ENSO can affect atmospheric phenomena that are capable of propagating upward to altitudes where E s occurs. This result illustrates a vertical connection in the atmosphere that has not been previously observed. Key Points: Extreme E region scintillation observed using 2007‐2016 COSMIC S 4 indices are proportionate to sporadic E occurrence Variation of E region zonal median extreme S 4 and tropopause height are correlated with ENSO from 2007 to 2014 This is a new manifestation of troposphere‐ionosphere coupling, especially in southern midlatitudes