Details

Autor(en) / Beteiligte

• Moral, Aysegul Ceren
• Shiokawa, Kazuo
• Suzuki, Shin
• Liu, Huixin
• Otsuka, Yuichi
• Yatini, Clara Yoko

Titel

Observations of Low‐Latitude Traveling Ionospheric Disturbances by a 630.0‐nm Airglow Imager and the CHAMP Satellite Over Indonesia

Ist Teil von

• Journal of geophysical research. Space physics, 2019-03, Vol.124 (3), p.2198-2212

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2019

Quelle

Wiley Online Library

Beschreibungen/Notizen

• We report the first comparison of ground and satellite measurements of low‐latitude traveling ionospheric disturbances (TIDs). Three TID events were simultaneously observed by a 630.0‐nm airglow imager and the CHAllenging Minisatellite Payload (CHAMP) satellite at Kototabang, Indonesia (geographic coordinates: 0.2° S, 100.3° E, geomagnetic latitude: 10.6° S). In 630.0‐nm airglow images of all three events, there are clear southward‐moving structures. Events 1 and 2 are a single pulse with horizontal scales of ∼500–1,000 km. Event 3 shows five wave fronts with a horizontal scale size of 500–1,000 km. All three TIDs are medium‐scale TIDs. Horizontal wavelengths of both airglow intensity at an average emission altitude of 250 km and CHAMP neutral density variations measured at 400 km are estimated by fitting a sinusoidal function to the observed data. The estimated horizontal wavelengths for airglow and neutral density data are 1,031 and 880 km for event 1 and 560 and 420 km for event 3, respectively. These values between airglow and CHAMP are comparable, suggesting both instruments are observing the same wave. For event 1, the CHAMP electron density mapped along the geomagnetic field line onto the airglow altitude does not show wave structure similar to the airglow variation. For events 2 and 3, the plasma density did not show wavy structures similar to the waves seen in the airglow image and CHAMP neutral density. These results suggest that the TIDs observed in airglow images are not caused by ionospheric plasma instability but by gravity waves in the thermosphere. Key Points We observed the traveling ionospheric disturbances (TIDs) at the low latitudes We used the simultaneous observations by 630.0‐nm airglow imager and the CHAMP satellite We concluded the TIDs caused by the gravity waves in the neutral atmosphere