Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes

Tam Dao, Yuichi Otsuka, Kazuo Shiokawa, Michi Nishioka, Mamoru Yamamoto, Suhaila M. Buhari, Mardina Abdullah, Asnawi Husin

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h′F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h′F at low-latitude stations, but h′F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs.

Original languageEnglish
Pages (from-to)7504-7518
Number of pages15
JournalJournal of Geophysical Research: Space Physics
Volume122
Issue number7
DOIs
Publication statusPublished - 1 Jul 2017

Fingerprint

irregularities
tropical regions
plasma bubbles
plasma
bubbles
F region
Plasmas
bubble
magnetic equator
temperature
equatorial atmosphere
Pedersen currents
Temperature
stations
Southeast Asia
Fabry-Perot interferometers
Indonesia
ionosondes
Plasma stability
airglow

Keywords

  • neutral temperatures
  • postmidnight field-aligned irregularities
  • the Equatorial Atmosphere Radar
  • thermospheric neutral winds

ASJC Scopus subject areas

  • Geophysics
  • Oceanography
  • Forestry
  • Ecology
  • Aquatic Science
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes. / Dao, Tam; Otsuka, Yuichi; Shiokawa, Kazuo; Nishioka, Michi; Yamamoto, Mamoru; Buhari, Suhaila M.; Abdullah, Mardina; Husin, Asnawi.

In: Journal of Geophysical Research: Space Physics, Vol. 122, No. 7, 01.07.2017, p. 7504-7518.

Research output: Contribution to journalArticle

Dao, Tam ; Otsuka, Yuichi ; Shiokawa, Kazuo ; Nishioka, Michi ; Yamamoto, Mamoru ; Buhari, Suhaila M. ; Abdullah, Mardina ; Husin, Asnawi. / Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes. In: Journal of Geophysical Research: Space Physics. 2017 ; Vol. 122, No. 7. pp. 7504-7518.
@article{0bd01195e9254b4cbfd0a3deb8bbf0b8,
title = "Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes",
abstract = "We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h′F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h′F at low-latitude stations, but h′F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs.",
keywords = "neutral temperatures, postmidnight field-aligned irregularities, the Equatorial Atmosphere Radar, thermospheric neutral winds",
author = "Tam Dao and Yuichi Otsuka and Kazuo Shiokawa and Michi Nishioka and Mamoru Yamamoto and Buhari, {Suhaila M.} and Mardina Abdullah and Asnawi Husin",
year = "2017",
month = "7",
day = "1",
doi = "10.1002/2017JA024048",
language = "English",
volume = "122",
pages = "7504--7518",
journal = "Journal of Geophysical Research",
issn = "2169-9380",
publisher = "American Geophysical Union",
number = "7",

}

TY - JOUR

T1 - Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes

AU - Dao, Tam

AU - Otsuka, Yuichi

AU - Shiokawa, Kazuo

AU - Nishioka, Michi

AU - Yamamoto, Mamoru

AU - Buhari, Suhaila M.

AU - Abdullah, Mardina

AU - Husin, Asnawi

PY - 2017/7/1

Y1 - 2017/7/1

N2 - We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h′F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h′F at low-latitude stations, but h′F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs.

AB - We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h′F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h′F at low-latitude stations, but h′F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs.

KW - neutral temperatures

KW - postmidnight field-aligned irregularities

KW - the Equatorial Atmosphere Radar

KW - thermospheric neutral winds

UR - http://www.scopus.com/inward/record.url?scp=85021775124&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85021775124&partnerID=8YFLogxK

U2 - 10.1002/2017JA024048

DO - 10.1002/2017JA024048

M3 - Article

AN - SCOPUS:85021775124

VL - 122

SP - 7504

EP - 7518

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 2169-9380

IS - 7

ER -