First results of the limb imaging of 630.0 nm airglow using FORMOSAT‐2/Imager of Sprites and Upper Atmospheric Lightnings

Rajesh, P. K.; Liu, J. Y.; Chiang, Che‐Ming; Chen, Alfred; Chen, W. S.; Su, H.; Hsu, R.; Lin, Charles; Hsu, Ming-Ying; Yee, Jeng‐Hwa; Nee, J. B.

doi:10.1029/2009ja014087

Cited by 9 publications

(16 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, statistical results regarding the location of nightglow bright spots agree with the simulation results that demonstrate the crucial role of the neutral wind in affecting the location of high-intensity nightglow regions. Rajesh et al (2014) showed their simulation results and claimed that using merely the background meridional winds could reproduce the observed brightness. They selected a few cases of ISUAL image data and compared those data with the simulation results by the SAMI2 model.…”

Section: Discussionmentioning

confidence: 99%

“…They selected a few cases of ISUAL image data and compared those data with the simulation results by the SAMI2 model. Nevertheless, using such a method by Rajesh et al (2014), one should be very careful about the details when it comes to physical insights or conclusions drawn from the study. This is because ISUAL only provided optical data and there was not any instrument on the satellite to directly observe the relevant conditions (temperature, wind field, etc.)…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Variations of the 630.0 nm airglow emission with meridional neutral wind and neutral temperature around midnight

2018

View full text Add to dashboard Cite

Abstract. The ISUAL payload onboard the FORMOSAT-2 satellite has often observed airglow bright spots around midnight at equatorial latitudes. Such features had been suggested as the signature of the thermospheric midnight temperature maximum (MTM) effect, which was associated with temperature and meridional neutral winds. This study investigates the influence of neutral temperature and meridional neutral wind on the volume emission rates of the 630.0 nm nightglow. We utilize the SAMI2 model to simulate the charged and neutral species at the 630.0 nm nightglow emission layer under different temperatures with and without the effect of neutral wind. The results show that the neutral wind is more efficient than temperature variation in affecting the nightglow emission rates. For example, based on our estimation, it would require a temperature change of 145 K to produce a change in the integrated emission rate by 9.8 km-photons cm−3 s−1, while it only needs the neutral wind velocity to change by 1.85 m−1 s−1 to cause the same change in the integrated emission rate. However, the emission rate features a local maximum in its variation with the temperature. Two kinds of tendencies can be seen regarding the temperature that corresponds to the turning point, which is named the turning temperature (Tt) in this study: firstly, Tt decreases with the emission rate for the same altitude; secondly, for approximately the same emission rate, Tt increases with the altitude.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Variations of the 630.0 nm airglow emission with meridional neutral wind and neutral temperature around midnight

2018

View full text Add to dashboard Cite

show abstract

“…Second in the series of “FORMOSATs” developed by Taiwan, the FORMOSAT‐2 homes the set of optical instruments acronymed ISUAL, which includes a CCD imager that images the Earth's limb at 630.0 nm wavelength in high spatial and temporal resolutions [ Chern et al ., ]. The limb‐viewing geometry of ISUAL provides a unique opportunity to examine the characteristics of 630.0 nm emission in great detail and to infer the electrodynamical processes involved in the intensity variations during the midnight period [ Rajesh et al ., , ; Adachi et al ., ]. In addition, many of the images also reveal wavelike patterns of intensity modulation or regularly spaced distinct bands of enhancement, suggesting that they could be the optical signatures of MSTIDs in airglow images when viewed from space [for example, see, Adachi et al ., ].…”

Section: Analysis Of Mstid In Formosat‐2/isual Imagesmentioning

confidence: 99%

“…[] presented a case study of concurrent MSTID events in 630.0 nm airglow image taken by Imager of Sprites and Upper Atmospheric Lightnings (ISUAL) on board FORMOSAT‐2 satellite and ground‐based all‐sky imager. The ISUAL provides continuous latitudinal coverage of line‐of‐sight integrated 630.0 nm intensity at the local midnight sector, with very high spatial and temporal resolutions [ Chern et al ., ; Rajesh et al ., ]. In this study, extensive analysis of the space‐based airglow images by ISUAL is carried out to identify such intensity perturbations with preferential azimuthal orientation caused by MSTID propagation during nighttime.…”

Section: Introductionmentioning

confidence: 99%

Space‐based imaging of nighttime medium‐scale traveling ionospheric disturbances using FORMOSAT‐2/ISUAL 630.0 nm airglow observations

et al. 2016

Self Cite

View full text Add to dashboard Cite

This paper reports the results of space‐based imaging of nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) in 630.0 nm emission by Imager of Sprites and Upper Atmospheric Lightnings (ISUAL), on board FORMOSAT‐2 satellite. The limb integrated measurements, after removing background, reveal multiple bands of intensity perturbation when projected to a horizontal plane corresponding to the altitude of peak emission, with distinct southwest to northeast orientation in the Southern Hemisphere. Simulations are carried out by artificially introducing MSTID fluctuations in model electron density to confirm if the MSTID could be identified in the ISUAL‐viewing geometry. The ISUAL observations in year 2007 are further used to investigate the MSTID features as well as occurrence characteristics in the Southern Hemisphere, most of which are over the ocean where no ground‐based observations are available. The preliminary statistics shows more MSTID occurrence in solstices with peak in June–July months. Majority of the MSTID perturbations have wavelength in the range 150–300 km, and the wavefronts are aligned at about 30°–50° from the east‐west plane. The statistic results of the orientation of wavefronts indicate that Es layer instability might be important in the MSTID generation.

show abstract

“…Recent limb imaging observations by ISUAL on the FORMOSAT‐2 satellite uncovered the global distribution of 630 nm airglow in the midnight region. Rajesh et al [2009], analyzing ISUAL‐obtained airglow data, discussed the latitudinal distributions of OI and OH airglows. The satellite viewing geometry, however, was not calibrated and true altitude profiles remained unknown.…”

Section: Introductionmentioning

confidence: 99%

Midnight latitude‐altitude distribution of 630 nm airglow in the Asian sector measured with FORMOSAT‐2/ISUAL

et al. 2010

View full text Add to dashboard Cite

[1] The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) payload on board the FORMOSAT-2 satellite carried out the first limb imaging observation of 630 nm airglow for the purpose of studying physical processes in the F region ionosphere. For a total of 14 nights in 2006-2008, ISUAL scanned the midnight latitude-altitude distribution of 630 nm airglow in the Asian sector. On two nights of relatively active conditions (SKp = 26, 30+) we found several bright airglow regions, which were highly variable each night in terms of luminosity and location. In relatively quiet conditions (SKp = 4-20) near May/June we found two bright regions which were stably located in the midlatitude region of 40°S-10°S (50°S-20°S magnetic latitude (MLAT)) and in the equatorial region of 0°-10°N (10°S-0°MLAT). On one of the quiet nights, FORMOSAT-3/COSMIC and CHAMP simultaneously measured the plasma density in the same region where ISUAL observed airglow. The plasma density data generally show good agreement, suggesting that plasma enhancements were the primary source of these two bright airglow regions. From detailed comparison with past studies we explain that the airglow in the equatorial region was due to the midnight brightness wave produced in association with the midnight temperature maximum, while that in the midlatitude region was due to the typical plasma distribution usually formed in the midnight sector. The fact that the equatorial airglow was much brighter than the midlatitude airglow and was observed on most nights during the campaign period strongly suggests the importance of further studies on the MTM/MBW phenomenology, which is not well reproduced in the current general circulation model.

show abstract

First results of the limb imaging of 630.0 nm airglow using FORMOSAT‐2/Imager of Sprites and Upper Atmospheric Lightnings

Cited by 9 publications

References 74 publications

Variations of the 630.0 nm airglow emission with meridional neutral wind and neutral temperature around midnight

Variations of the 630.0 nm airglow emission with meridional neutral wind and neutral temperature around midnight

Space‐based imaging of nighttime medium‐scale traveling ionospheric disturbances using FORMOSAT‐2/ISUAL 630.0 nm airglow observations

Midnight latitude‐altitude distribution of 630 nm airglow in the Asian sector measured with FORMOSAT‐2/ISUAL

Contact Info

Product

Resources

About