Articles | Volume 42, issue 1
https://doi.org/10.5194/angeo-42-131-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-42-131-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Simultaneous OI 630 nm imaging observations of thermospheric gravity waves and associated revival of fossil depletions around midnight near the equatorial ionization anomaly (EIA) crest
Indian Institute of Geomagnetism, Navi Mumbai, India
Saranya Padincharapad
Equatorial Geophysical Research Laboratory, Indian Institute of Geomagnetism, Tirunelveli, India
Manonmaniam Sundaranar University, Tirunelveli, India
Anand Kumar Singh
National Centre for Polar and Ocean Research, Goa, India
Prasanna Mahavarkar
Indian Institute of Geomagnetism, Navi Mumbai, India
Ashok Priyadarshan Dimri
Indian Institute of Geomagnetism, Navi Mumbai, India
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Weather Clim. Dynam., 6, 43–112, https://doi.org/10.5194/wcd-6-43-2025, https://doi.org/10.5194/wcd-6-43-2025, 2025
Short summary
Short summary
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Cited articles
Abdu, M. A., Alam Kherani, E., Batista, I. S., de Paula, E. R., Fritts, D. C., and Sobral, J. H. A.: Gravity wave initiation of equatorial spread F/plasma bubble irregularities based on observational data from the SpreadFEx campaign, Ann. Geophys., 27, 2607–2622, https://doi.org/10.5194/angeo-27-2607-2009, 2009. a
Abdu, M. A., Iyer, K. N., de Medeiros, R., Batista, I. S., and Sobral, J. H.: Thermospheric meridional wind control of equatorial spread F and evening prereversal electric field, Geophys. Res. Lett., 33, L07106, https://doi.org/10.1029/2005GL024835, 2006. a
Azeem, I. and Barlage, M.: Atmosphere-ionosphere coupling from convectively generated gravity waves, Adv. Space Res., 61, 1931–1941, https://doi.org/10.1016/j.asr.2017.09.029, 2018. a
Chapagain, N. P., Taylor, M. J., and Eccles, J. V.: Airglow observations and modeling of F region depletion zonal velocities over Christmas Island, J. Geophys. Res.-Space, 116, A02301, https://doi.org/10.1029/2010JA015958, 2011. a
Ciraolo, L., Azpilicueta, F., Brunini, C., Meza, A., and Radicella, S. M.: Calibration errors on experimental slant total electron content (TEC) determined with GPS, J. Geodesy, 81, 111–120, https://doi.org/10.1007/s00190-006-0093-1, 2007 (data available at: https://t-ict4d.ictp.it/nequick2/gnss-tec-calibration, last access: 1 May 2024). a
Devasia, C., Jyoti, N., Subbarao, K., Viswanathan, K., Tiwari, D., and Sridharan, R.: On the plausible linkage of thermospheric meridional winds with the equatorial spread F, J. Atmos. Sol.-Terr. Phy., 64, 1–12, https://doi.org/10.1016/S1364-6826(01)00089-X, 2002. a
Drob, D., Emmert, J., Crowley, G., Picone, J., Shepherd, G., Skinner, W., Hays, P., Niciejewski, R., Larsen, M., She, C., Meriwether, J. W., Hernandez, G., Jarvis, M. J., Sipler, D. P., Tepley, C. A., O'Brien, M. S., Bowman, J. R., Wu, Q., Murayama, Y., Kawamura, S., Reid, I. M., and Vincent, R. A.: An empirical model of the Earth's horizontal wind fields: HWM07, J. Geophys. Res.-Space, 113, A12304, https://doi.org/10.1029/2008JA013668, 2008. a
Fejer, B. and Kelley, M.: Ionospheric irregularities, Rev. Geophys., 18, 401–454, https://doi.org/10.1029/RG018i002p00401, 1980. a
Figueiredo, C. A. O. B., Takahashi, H., Wrasse, C. M., Otsuka, Y., Shiokawa, K., and Barros, D.: Medium-scale traveling ionospheric disturbances observed by detrended total electron content maps over Brazil, J. Geophys. Res.-Space, 123, 2215–2227, https://doi.org/10.1002/2017JA025021, 2018. a
Ford, E. A. K., Aruliah, A. L., Griffin, E. M., and McWhirter, I.: Thermospheric gravity waves in Fabry-Perot Interferometer measurements of the 630.0nm OI line, Ann. Geophys., 24, 555–566, https://doi.org/10.5194/angeo-24-555-2006, 2006. a
Ford, E. A. K., Aruliah, A. L., Griffin, E. M., and McWhirter, I.: Statistical analysis of thermospheric gravity waves from Fabry-Perot Interferometer measurements of atomic oxygen, Ann. Geophys., 26, 29–45, https://doi.org/10.5194/angeo-26-29-2008, 2008. a
Fritts, D. C., Abdu, M. A., Batista, B. R., Batista, I. S., Batista, P. P., Buriti, R., Clemesha, B. R., Dautermann, T., de Paula, E. R., Fechine, B. J., Fejer, B. G., Gobbi, D., Haase, J., Kamalabadi, F., Kherani, E. A., Laughman, B., Lima, P. P., Liu, H.-L., Medeiros, A., Pautet, P.-D., Riggin, D. M., Rodrigues, F. S., São Sabbas, F., Sobral, J. H. A., Stamus, P., Takahashi, H., Taylor, M. J., Vadas, S. L., Vargas, F., and Wrasse, C. M.: Overview and summary of the Spread F Experiment (SpreadFEx), Ann. Geophys., 27, 2141–2155, https://doi.org/10.5194/angeo-27-2141-2009, 2009. a, b, c, d
Fritts, D. C. and Alexander, M. J.: Gravity wave dynamics and effects in the middle atmosphere, Rev. Geophys., 41, 1003, https://doi.org/10.1029/2001RG000106, 2003. a
Fukushima, D., Shiokawa, K., Otsuka, Y., and Ogawa, T.: Observation of equatorial nighttime medium-scale traveling ionospheric disturbances in 630-nm airglow images over 7 years, J. Geophys. Res.-Space, 117, A10324, https://doi.org/10.1029/2012JA017758, 2012. a
Garcia, F., Taylor, M. J., and Kelley, M.: Two-dimensional spectral analysis of mesospheric airglow image data, Appl. Optics, 36, 7374–7385, https://doi.org/10.1364/AO.36.007374, 1997. a
Heale, C., Inchin, P., and Snively, J.: Primary versus secondary gravity wave responses at F-region heights generated by a convective source, J. Geophys. Res.-Space, 127, e2021JA029947, https://doi.org/10.1029/2021JA029947, 2022. a
Holton, J. R.: The influence of gravity wave breaking on the general circulation of the middle atmosphere, J. Atmos. Sci., 40, 2497–2507, 1983. a
Huang, C.-S. and Kelley, M. C.: Nonlinear evolution of equatorial spread F: 1. On the role of plasma instabilities and spatial resonance associated with gravity wave seeding, J. Geophys. Res.-Space, 101, 283–292, https://doi.org/10.1029/95JA02211, 1996. a
Huang, C.-S., Kelley, M., and Hysell, D.: Nonlinear Rayleigh-Taylor instabilities, atmospheric gravity waves and equatorial spread F, J. Geophys. Res.-Space, 98, 15631–15642, https://doi.org/10.1029/93JA00762, 1993. a
Huba, J. and Joyce, G.: Equatorial spread F modeling: Multiple bifurcated structures, secondary instabilities, large density “bite-outs,” and supersonic flows, Geophys. Res. Lett., 34, L07105, https://doi.org/10.1029/2006GL028519, 2007. a, b, c
Huba, J. and Joyce, G.: Global modeling of equatorial plasma bubbles, Geophys. Res. Lett., 37, L17104, https://doi.org/10.1029/2010GL044281, 2010. a, b
Huba, J. and Krall, J.: Impact of meridional winds on equatorial spread F: Revisited, Geophys. Res. Lett., 40, 1268–1272, https://doi.org/10.1002/grl.50292, 2013. a
Huba, J. and Liu, H.-L.: Global modeling of equatorial spread F with SAMI3/WACCM-X, Geophys. Res. Lett., 47, e2020GL088258, https://doi.org/10.1029/2020GL088258, 2020. a, b, c, d
Huba, J., Joyce, G., and Krall, J.: Three-dimensional equatorial spread F modeling, Geophys. Res. Lett., 35, L10102, https://doi.org/10.1029/2008GL033509, 2008. a
Huba, J., Drob, D., Wu, T.-W., and Makela, J.: Modeling the ionospheric impact of tsunami-driven gravity waves with SAMI3: Conjugate effects, Geophys. Res. Lett., 42, 5719–5726, https://doi.org/10.1002/2015GL064871, 2015. a, b, c
Hysell, D., Kelley, M., Swartz, W., and Woodman, R.: Seeding and layering of equatorial spread F by gravity waves, J. Geophys. Res.-Space, 95, 17253–17260, https://doi.org/10.1029/JA095iA10p17253, 1990. a, b, c
Hysell, D., Jafari, R., Fritts, D., and Laughman, B.: Gravity wave effects on postsunset equatorial F region stability, J. Geophys. Res.-Space, 119, 5847–5860, https://doi.org/10.1002/2014JA019990, 2014. a, b, c
Kelley, M., Larsen, M., LaHoz, C., and McClure, J.: Gravity wave initiation of equatorial spread F: A case study, J. Geophys. Res.-Space, 86, 9087–9100, https://doi.org/10.1029/JA086iA11p09087, 1981. a, b, c
Klausner, V., Fagundes, P. R., Sahai, Y., Wrasse, C. M., Pillat, V. G., and Becker-Guedes, F.: Observations of GW/TID oscillations in the F2 layer at low latitude during high and low solar activity, geomagnetic quiet and disturbed periods, J. Geophys. Res.-Space, 114, A02313, https://doi.org/10.1029/2008JA013448, 2009. a
Krall, J., Huba, J., Ossakow, S., Joyce, G., Makela, J., Miller, E., and Kelley, M.: Modeling of equatorial plasma bubbles triggered by non-equatorial traveling ionospheric disturbances, Geophys. Res. Lett., 38, L08103, https://doi.org/10.1029/2011GL046890, 2011. a
Krall, J., Huba, J., and Fritts, D.: On the seeding of equatorial spread F by gravity waves, Geophys. Res. Lett., 40, 661–664, https://doi.org/10.1002/grl.50144, 2013. a, b
Liu, H.-L., Foster, B. T., Hagan, M. E., McInerney, J. M., Maute, A., Qian, L., Richmond, A. D., Roble, R. G., Solomon, S. C., Garcia, R. R., Kinnison, D., Marsh, D. R., Smith, A. K., Richter, J., Sassi, F., and Oberheide, J.: Thermosphere extension of the whole atmosphere community climate model, J. Geophys. Res.-Space, 115, A12302, https://doi.org/10.1029/2010JA015586, 2010. a
Makela, J. J., Ledvina, B. M., Kelley, M. C., and Kintner, P. M.: Analysis of the seasonal variations of equatorial plasma bubble occurrence observed from Haleakala, Hawaii, Ann. Geophys., 22, 3109–3121, https://doi.org/10.5194/angeo-22-3109-2004, 2004. a
Makela, J., Kelley, M., and Nicolls, M.: Optical observations of the development of secondary instabilities on the eastern wall of an equatorial plasma bubble, J. Geophys. Res.-Space, 111, A09311, https://doi.org/10.1029/2006JA011646, 2006. a
Makela, J., Lognonné, P., Hébert, H., Gehrels, T., Rolland, L., Allgeyer, S., Kherani, A., Occhipinti, G., Astafyeva, E., Coïsson, P., Loevenbruck, A. , Clévédé, E., Kelley, M. C., and Lamouroux, J.: Imaging and modeling the ionospheric airglow response over Hawaii to the tsunami generated by the Tohoku earthquake of 11 March 2011, Geophys. Res. Lett., 38, L00G02, https://doi.org/10.1029/2011GL047860, 2011. a, b, c, d
Makela, J. J. and Otsuka, Y.: Overview of nighttime ionospheric instabilities at low-and mid-latitudes: Coupling aspects resulting in structuring at the mesoscale, Space Sci. Rev., 168, 419–440, https://doi.org/10.1007/s11214-011-9816-6, 2012. a
Maruyama, T.: A diagnostic model for equatorial spread F, 1, Model description and application to electric field and neutral wind effects, J. Geophys. Res.-Space, 93, 14611–14622, https://doi.org/10.1029/JA093iA12p14611, 1988. a
Maurya, A. K., Parihar, N., Dube, A., Singh, R., Kumar, S., Chanrion, O., Tomicic, M., and Neubert, T.: Rare observations of sprites and gravity waves supporting D, E, F-regions ionospheric coupling, Sci. Rep.-UK, 12, 581, https://doi.org/10.1038/s41598-021-03808-5, 2022. a
Mendillo, M. and Baumgardner, J.: Airglow characteristics of equatorial plasma depletions, J. Geophys. Res.-Space, 87, 7641–7652, https://doi.org/10.1029/JA087iA09p07641, 1982. a
Mendillo, M., Baumgardner, J., Colerico, M., and Nottingham, D.: Imaging science contributions to equatorial aeronomy: initial results from the MISETA program, J. Atmos. Sol.-Terr. Phy., 59, 1587–1599, https://doi.org/10.1016/S1364-6826(96)00158-7, 1997. a
Miller, E., Makela, J., and Kelley, M.: Seeding of equatorial plasma depletions by polarization electric fields from middle latitudes: Experimental evidence, Geophys. Res. Lett., 36, L18105, https://doi.org/10.1029/2009GL039695, 2009. a, b
Mukherjee, G., Pragati Shikha, R., Parihar, N., Ghodpage, R., and Patil, P.: Studies of the wind filtering effect of gravity waves observed at Allahabad (25.45° N, 81.85° E) in India, Earth Planet. Space, 62, 309–318, https://doi.org/10.5047/eps.2009.11.008, 2010. a
Nishioka, M., Otsuka, Y., Shiokawa, K., Tsugawa, T., Effendy, n., Supnithi, P., Nagatsuma, T., and Murata, K.: On post-midnight field-aligned irregularities observed with a 30.8-MHz radar at a low latitude: Comparison withF-layer altitude near the geomagnetic equator, J. Geophys. Res.-Space, 117, A08337, https://doi.org/10.1029/2012JA017692, 2012. a
Otsuka, Y.: Review of the generation mechanisms of post-midnight irregularities in the equatorial and low-latitude ionosphere, Prog. Earth Planet. Sci., 5, 1–13, https://doi.org/10.1186/s40645-018-0212-7, 2018. a
Otsuka, Y., Shiokawa, K., and Ogawa, T.: Disappearance of equatorial plasma bubble after interaction with mid-latitude medium-scale traveling ionospheric disturbance, Geophys. Res. Lett., 39, L14105, https://doi.org/10.1029/2012GL052286, 2012. a, b
Parihar, N.: Rare occurrence of off-equatorial edge initiating and equatorward surging plasma depletions observed in OI 630-nm imaging, J. Geophys. Res.-Space, 124, 2887–2896, https://doi.org/10.1029/2018JA026155, 2019. a
Parihar, N.: OI 630 nm Airglow Images for 20120416, Zenodo [data set], https://doi.org/10.5281/zenodo.8143215, 2023. a
Parihar, N.: Movie showing GWs Driven Revival of Fossil Depletions around Midnight on 16 April 2012, Zenodo [video], https://doi.org/10.5281/zenodo.10851669, 2024. a
Parihar, N., Singh, D., and Gurubaran, S.: A comparison of ground-based hydroxyl airglow temperatures with SABER/TIMED measurements over 23° N, India, Ann. Geophys., 35, 353–363, https://doi.org/10.5194/angeo-35-353-2017, 2017. a
Parihar, N., Radicella, S. M., Nava, B., Migoya-Orue, Y. O., Tiwari, P., and Singh, R.: An investigation of the ionospheric F region near the EIA crest in India using OI 777.4 and 630.0 nm nightglow observations, Ann. Geophys., 36, 809–823, https://doi.org/10.5194/angeo-36-809-2018, 2018. a
Paulino, I., Takahashi, H., Medeiros, A. F. d., Wrasse, C. M., Buriti, R. A., Sobral, J. H. D. A., and Gobbi, D.: Mesospheric gravity waves and ionospheric plasma bubbles observed during the COPEX campaign, J. Atmos. Sol.-Terr. Phy., 73, 1575–1580, https://doi.org/10.1016/j.jastp.2010.12.004, 2011. a
Paulino, I., Medeiros, A. F., Vadas, S. L., Wrasse, C. M., Takahashi, H., Buriti, R. A., Leite, D., Filgueira, S., Bageston, J. V., Sobral, J. H. A., and Gobbi, D.: Periodic waves in the lower thermosphere observed by OI630 nm airglow images, Ann. Geophys., 34, 293–301, https://doi.org/10.5194/angeo-34-293-2016, 2016. a, b
Paulino, I., Moraes, J. F., Maranhão, G. L., Wrasse, C. M., Buriti, R. A., Medeiros, A. F., Paulino, A. R., Takahashi, H., Makela, J. J., Meriwether, J. W., and Campos, J. A. V.: Intrinsic parameters of periodic waves observed in the OI6300 airglow layer over the Brazilian equatorial region, Ann. Geophys., 36, 265–273, https://doi.org/10.5194/angeo-36-265-2018, 2018. a, b
Pimenta, A. A., Fagundes, P. R., Sahai, Y., Bittencourt, J. A., and Abalde, J. R.: Equatorial F-region plasma depletion drifts: latitudinal and seasonal variations, Ann. Geophys., 21, 2315–2322, https://doi.org/10.5194/angeo-21-2315-2003, 2003. a, b
Sau, S., Narayanan, V. L., Gurubaran, S., and Emperumal, K.: Study of wave signatures observed in thermospheric airglow imaging over the dip equatorial region, Adv. Space Res., 62, 1762–1774, https://doi.org/10.1016/j.asr.2018.06.039, 2018. a, b, c
Sekar, R., Chakrabarty, D., Sarkhel, S., Patra, A. K., Devasia, C. V., and Kelley, M. C.: Identification of active fossil bubbles based on coordinated VHF radar and airglow measurements, Ann. Geophys., 25, 2099–2102, https://doi.org/10.5194/angeo-25-2099-2007, 2007. a
Shiokawa, K., Otsuka, Y., Lynn, K. J., Wilkinson, P., and Tsugawa, T.: Airglow-imaging observation of plasma bubble disappearance at geomagnetically conjugate points, Earth Planet. Space, 67, 1–12, https://doi.org/10.1186/s40623-015-0202-6, 2015. a
Singh, S., Johnson, F., and Power, R.: Gravity wave seeding of equatorial plasma bubbles, J. Geophys. Res.-Space, 102, 7399–7410, https://doi.org/10.1029/96JA03998, 1997. a
Smith, S. M., Martinis, C. R., Baumgardner, J., and Mendillo, M.: All-sky imaging of transglobal thermospheric gravity waves generated by the March 2011 Tohoku Earthquake, J. Geophys. Res.-Space, 120, 10992–10999, https://doi.org/10.1002/2015JA021638, 2015. a, b
Sreeja, V., Vineeth, C., Pant, T. K., Ravindran, S., and Sridharan, R.: Role of gravity wavelike seed perturbations on the triggering of ESF – a case study from unique dayglow observations, Ann. Geophys., 27, 313–318, https://doi.org/10.5194/angeo-27-313-2009, 2009. a
Takahashi, H., Taylor, M. J., Pautet, P.-D., Medeiros, A. F., Gobbi, D., Wrasse, C. M., Fechine, J., Abdu, M. A., Batista, I. S., Paula, E., Sobral, J. H. A., Arruda, D., Vadas, S. L., Sabbas, F. S., and Fritts, D. C.: Simultaneous observation of ionospheric plasma bubbles and mesospheric gravity waves during the SpreadFEx Campaign, Ann. Geophys., 27, 1477–1487, https://doi.org/10.5194/angeo-27-1477-2009, 2009. a
Takahashi, H., Wrasse, C. M., Figueiredo, C. A. O. B., Barros, D., Paulino, I., Essien, P., Abdu, M. A., Otsuka, Y., and Shiokawa, K.: Equatorial plasma bubble occurrence under propagation of MSTID and MLT gravity waves, J. Geophys. Res.-Space, 125, e2019JA027566, https://doi.org/10.1029/2019JA027566, 2020. a
Takahashi, H., Essien, P., Figueiredo, C. A. O. B., Wrasse, C. M., Barros, D., Abdu, M. A., Otsuka, Y., Shiokawa, K., and Li, G.: Multi-instrument study of longitudinal wave structures for plasma bubble seeding in the equatorial ionosphere, Earth Planet. Phys., 5, 368–377, https://doi.org/10.26464/epp2021047, 2021. a
Taori, A., Makela, J., and Taylor, M.: Mesospheric wave signatures and equatorial plasma bubbles: a case study, J. Geophys. Res.-Space, 115, A06302, https://doi.org/10.1029/2009JA015088, 2010. a
Taori, A., Jayaraman, A., and Kamalakar, V.: Imaging of mesosphere–thermosphere airglow emissions over Gadanki (13.5° N, 79.2° E) – First results, J. Atmos. Sol.-Terr. Phy., 93, 21–28, https://doi.org/10.1016/j.jastp.2012.11.007, 2013. a
Taori, A., Parihar, N., Ghodpage, R., Dashora, N., Sripathi, S., Kherani, E., and Patil, P.: Probing the possible trigger mechanisms of an equatorial plasma bubble event based on multistation optical data, J. Geophys. Res.-Space, 120, 8835–8847, https://doi.org/10.1002/2015JA021541, 2015. a, b
Tsunoda, R. T.: On seeding equatorial spread F: Circular gravity waves, Geophys. Res. Lett., 37, L10104, https://doi.org/10.1029/2010GL043422, 2010. a, b, c
Tulasi Ram, S., Yamamoto, M., Tsunoda, R., Chau, H., Hoang, T., Damtie, B., Wassaie, M., Yatini, C., Manik, T., and Tsugawa, T.: Characteristics of large-scale wave structure observed from African and Southeast Asian longitudinal sectors, J. Geophys. Res.-Space, 119, 2288–2297, https://doi.org/10.1002/2013JA019712, 2014. a, b, c
Vadas, S. L. and Azeem, I.: Concentric secondary gravity waves in the thermosphere and ionosphere over the continental United States on March 25–26, 2015 from deep convection, J. Geophys. Res.-Space, 126, e2020JA028275, https://doi.org/10.1029/2020JA028275, 2021. a
Woodman, R. F.: Spread F – an old equatorial aeronomy problem finally resolved?, Ann. Geophys., 27, 1915–1934, https://doi.org/10.5194/angeo-27-1915-2009, 2009. a, b, c
Wrasse, C. M., Figueiredo, C. A. O. B., Barros, D., Takahashi, H., Carrasco, A. J., Vital, L. F. R., Resende, L. C. A., Egito, F., Rosa, G. D. M., and Sampaio, A. H. R.: Interaction between Equatorial Plasma Bubbles and a Medium-Scale Traveling Ionospheric Disturbance, observed by OI 630 nm airglow imaging at Bom Jesus de Lapa, Brazil, Earth Planet. Phys., 5, 397–406, https://doi.org/10.26464/epp2021045, 2021. a, b, c
Yadav, S., Sridharan, R., Sunda, S., and Pant, T. K.: Further refinements to the spatiotemporal forecast model for L-band scintillation based on comparison with C/NOFS observations, J. Geophys. Res.-Space, 122, 5643–5652, https://doi.org/10.1002/2017JA023869, 2017. a
Zalesak, S. and Ossakow, S.: Nonlinear equatorial spread F: Spatially large bubbles resulting from large horizontal scale initial perturbations, J. Geophys. Res.-Space, 85, 2131–2142, https://doi.org/10.1029/JA085iA05p02131, 1980. a
Short summary
Gravity waves are well known for deforming the bottom-side plasma of the F region into the wavelike ionization structures which then act as a seed for Rayleigh–Taylor instability, which in turn generates irregularities. The present study features midnight fossil airglow depletions that revived due to ongoing gravity wave (GW) activity and turned into an active depletion.
Gravity waves are well known for deforming the bottom-side plasma of the F region into the...