ANGEO Annales Geophysicae ANGEO 1432-0576 Copernicus GmbH Göttingen, Germany 10.5194/angeo-29-1529-2011 Initial daytime and nighttime SOFDI observations of thermospheric winds from Fabry-Perot Doppler shift measurements of the 630-nm OI line-shape profile Gerrard A. J. 1 Meriwether J. W. 2 Center for Solar-Terrestrial Research, Department of Physics, 323 Martin Luther King Boulevard, 101 Tiernan Hall, Newark, NJ 07102-1982, USA Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978, USA 02 09 2011 29 9 1529 1536 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.ann-geophys.net/29/1529/2011/angeo-29-1529-2011.html The full text article is available as a PDF file from http://www.ann-geophys.net/29/1529/2011/angeo-29-1529-2011.pdf

In this paper we present both night and day thermospheric wind observations made with the Second-generation, Optimized, Fabry-Perot Doppler Imager (SOFDI), a novel triple-etalon Fabry-Perot interferometer (FPI) designed to make 24-h measurements of thermospheric winds from OI 630-nm emission. These results were obtained from the northeastern United States and from under the magnetic equator at Huancayo, Peru and demonstrate the current instrument capability for measurements of Doppler shifts for either night or day. We found the uncertainties in the measurements agree with expected values based upon forward modeling calculations; nighttime wind components having an uncertainty of ~20-m s<sup>−1</sup> at 30-min resolution and daytime wind components having an uncertainty of ~70-m s<sup>−1</sup> at 20-min resolution. The nighttime uncertainties are typically larger than those seen with traditional single-etalon FPIs, which occur at the cost of being able to achieve daytime measurements. The thermospheric wind measurements from Huancayo replicate recently reported CHAMP zonal winds and are in disagreement with current empirical wind climatologies. In addition, we discuss the incorporation of how multiple point heads in the SOFDI instrument will allow for unique studies of gravity wave activity in future measurements.

 References Barmore, F E.: The Filling-In of Fraunhofer Lines in the Day Sky., J. Atmos. Sci., 32, 1489–1493, http://dx.doi.org/10.1175/1520-0469(1975)032<1489:TFIOFL>2.0.CO;2doi:10.1175/1520-0469(1975)032<1489:TFIOFL>2.0.CO;2, 1975. Barmore, F E.: High resolution observations of the 6300 Å oxygen line in the day airglow, Planet. Space Sci., 25, 185–191, http://dx.doi.org/10.1016/0032-0633(77)90023-Xdoi:10.1016/0032-0633(77)90023-X, 1977. Cocks, T D. and Jacka, F.: Daytime thermospheric temperatures, wind velocities and emission intensities derived from ground based observations of the O I lambda 630 nm airglow line profile, J. Atmos. Terr. Phys., 41, 409–415, 1979. Conde, M. and Jacka, F.: Analysis of day-time observations of the 630 nm thermospheric emission over Mawson, Antarctica, ANARE Res. Notes, 69, 125–138, 1989. Drob, D P., Emmert, J T., Crowley, G., Picone, J M., Shepherd, G G., Skinner, W., Hays, P., Niciejewski, R J., Larsen, M., She, C Y., 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., 113, 12304, http://dx.doi.org/10.1029/2008JA013668doi:10.1029/2008JA013668, 2008. Emmert, J T., Fejer, B G., and Sipler, D P.: Climatology and latitudinal gradients of quiet time thermospheric neutral winds over Millstone Hill from Fabry-Perot interferometer measurements, J. Geophys. Res., 108, 1196, http://dx.doi.org/10.1029/2002JA009765doi:10.1029/2002JA009765, 2003. Emmert, J T., Drob, D P., Shepherd, G G., Hernandez, G., Jarvis, M J., Meriwether, J W., Niciejewski, R J., Sipler, D P., and Tepley, C A.: DWM07 global empirical model of upper thermospheric storm-induced disturbance winds, J. Geophys. Res., 113, 11319, http://dx.doi.org/10.1029/2008JA013541doi:10.1029/2008JA013541, 2008. Gerrard, A J., Meriwether, J W., Goncharenko, L P., Hedden, R B., and Kelley, M.: Comparisons of neutral thermospheric winds as measured by SOFDI and the Millstone Hill Incoherent Scatter Radar, AGU Spring Meeting Abstracts, pp. A22+, 2009. Hays, P B. and HRDI Science Team: Remote sensing of mesospheric winds with the high-resolution doppler imager, Planet. Space Sci., 40, 1599–1606, http://dx.doi.org/10.1016/0032-0633(92)90119-9doi:10.1016/0032-0633(92)90119-9, 1992. Hernandez, G.: Fabry-Perot Interferometers, Cambridge Studies in Modern Optics, Cambridge: University Press, 1986, 1986. Hernandez, G. and Roble, R G.: Thermospheric dynamics investigations with very high resolution spectrometers, Appl. Optics, 18, 3376–3385, 1979. Hysell, D L. and Kudeki, E.: Collisional shear instability in the equatorial F region ionosphere, J. Geophys. Res., 109, 11301, http://dx.doi.org/10.1029/2004JA010636doi:10.1029/2004JA010636, 2004. Kelley, M C.: The Earth's Ionosphere: Plasma Physics and Electrodynamics, 2nd edition, Elsevier, London, 2009. Kosch, M. J., Ishii, M., Nozawa, S., Rees, D., Cierpka, K., Kohsiek, A., Schlegel, K., Fujii, R., Hagfors, T., Fuller-Rowell, T. J., and Lathuillere, C.: A comparison of thermospheric winds and temperatures from Fabry-Perot interferometer and EISCAT radar measurements with models, Adv. Space Res., 26(6), 979–984, 2000. Kudeki, E., Akgiray, A., Milla, M., Chau, J L., and Hysell, D L.: Equatorial spread-F initiation: Post-sunset vortex, thermospheric winds, gravity waves, J. Atmos. Solar-Terr. Phys., 69, 2416–2427, http://dx.doi.org/10.1016/j.jastp.2007.04.012doi:10.1016/j.jastp.2007.04.012, 2007. Liu, H., Lühr, H., Watanabe, S., Köhler, W., Henize, V., and Visser, P.: Zonal winds in the equatorial upper thermosphere: Decomposing the solar flux, geomagnetic activity, and seasonal dependencies, J. Geophys. Res., 111, A07307, http://dx.doi.org/10.1029/2005JA011415doi:10.1029/2005JA011415, 2006. Liu, H., Watanabe, S., and Kondo, T.: Fast thermospheric wind jet at the Earth's dip equator, Geophys. Res. Lett., 36, L08103, http://dx.doi.org/10.1029/2009GL037377doi:10.1029/2009GL037377, 2009. Meriwether, J W.: Studies of thermospheric dynamics with a Fabry-Perot interferometer network: A review, J. Atmos. Solar-Terr. Phys., 68, 1576–1589, 2006. Noxon, J F., Whipple, Jr., E C., and Hyde, R S.: Stratospheric NO2. I – Observational method and behavior at mid-latitude, J. Geophys. Res., 84, 5047–5065, http://dx.doi.org/10.1029/JC084iC08p05047doi:10.1029/JC084iC08p05047, 1979. Oliver, W L., Fukao, S., Yamamoto, Y., Takami, T., Yamanaka, M D., Yamamoto, M., Nakamura, T., and Tsuda, T.: Middle and upper atmosphere radar observations of ionospheric density gradients produced by gravity wave packets, J. Geophys. Res., 99, 6321–6329, http://dx.doi.org/10.1029/94JA00171doi:10.1029/94JA00171, 1994. Pallamraju, D. and Chakrabarti, S.: First ground-based measurements of OI 6300 Å daytime aurora over Boston in response to the 30 October 2003 geomagnetic storm, Geophys. Res. Lett., 32, 3, http://dx.doi.org/10.1029/2004GL021417doi:10.1029/2004GL021417, 2005. Pallamraju, D. and Chakrabarti, S.: Contributions of imaging Echelle spectrographs to daytime optical aeronomy, J. Atmos. Solar-Terr. Phys., 68, 1459–1471, http://dx.doi.org/10.1016/j.jastp.2005.05.013doi:10.1016/j.jastp.2005.05.013, 2006. Pallamraju, D., Baumgardner, J., and Chakrabarti, S.: HIRISE: a ground-based high-resolution imaging spectrograph using echelle grating for measuring daytime airglow/auroral emissions, J. Atmos. Solar-Terr. Phys., 64, 1581–1587, http://dx.doi.org/10.1016/S1364-6826(02)00095-0doi:10.1016/S1364-6826(02)00095-0, 2002. Skinner, W R., Hays, P B., and Abreu, V J.: Optimization of a triple etalon interferometer, Appl. Optics, 26, 2817–2827, 1987. Solomon, S C. and Abreu, V J.: The 630 nm dayglow, J. Geophys. Res., 94, 6817–6824, http://dx.doi.org/10.1029/JA094iA06p06817doi:10.1029/JA094iA06p06817, 1989. Tepley, C A., Meriwether Jr., J W., Walker, J C G., and Mathews, J D.: Observations of neutral iron emission in twilight spectra, J. Geophys. Res., 86, 4831–4835, http://dx.doi.org/10.1029/JA086iA06p04831doi:10.1029/JA086iA06p04831, 1981. Zhang, S P. and Shepherd, G G.: Solar influence on the O$(^1D)$ dayglow emission rate: Global-scale measurements by WINDII on UARS, Geophys. Res. Lett., 31, L07804, http://dx.doi.org/10.1029/2004GL019447doi:10.1029/2004GL019447, 2004.