Abstract
The recent years have brought enormous progress in our understanding of the characteristics and the variability of the thermosphere. This is to a good part based on the high-resolution measurements of the accelerometer on board the CHAMP satellite. It sampled the air drag from the solar maximum in 2001 to the minimum in 2009. The thermosphere reacts quite differently to solar and magnetic forcing. This is in particular evident when comparing the mass density on the day and night sides at low latitudes. We were able to delineate the variations due to solar flux, season, and magnetic activity. Another important finding is the close relation of thermospheric features to the geomagnetic field geometry. Examples of this are the equatorial mass density anomaly, the cusp density anomaly, and the high-speed wind channel along the dip equator. None of these phenomena is so far considered in any of the atmospheric models. Thermospheric wind is a prime driver for ionospheric dynamics. As an example we present the F-region dynamo current system and its variation with local time. This wind-driven dynamo over the equator is assumed to cause special ionospheric effects after sunset. Typical post-sunset features at low latitude are the equatorial plasma bubbles. Here it is shown that some of these bubbles are accompanied by depletions in neutral density. Neutral depletions can form only when the ion-neutral friction is high enough. In the pressure balance equation, the neutral depletions make up a significant part. The comprehensive set of CHAMP neutral and plasma measurements enabled us to interpret the ionosphere–thermosphere as a coupled system.
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- 1.
P10.7 = 0.5 (F10.7 + F10.7a), where F10.7a is the 81-day running average of the daily F10.7.
References
Bencze P, Almár I, Illés-Almár E (2000) Further results referring to the neutral density depletions attributed to plasma bubbles. J Atmos Solar-Terr Phys 62:1339
Fuller-Rowell, TJ, Codrescu MV, Fejer BG, Borer W, Marcos F, Anderson DN (1997) Dynamics of the low-latitude thermosphere: quiet and disturbed conditions. J Atmos Solar-Terr Phys 61:1533–1540
Guo J, Wan W, Forbes JM, Sutton E, Nerem RS, Woods TN, Bruinsma S, Liu L (2007) Effects of solar variability on thermosphere density from CHAMP accelerometer data. J Geophys Res 112:A10308. http://doi:10.1029/2007JA012409
Illés-Almár E, Almár I, Bencze P (1998) Neutral density depletions attributed to plasma bubbles. J Geophys Res 103(A3):4115
Liu H, Lühr H, Henize V, Köhler W (2005) Global distribution of the thermospheric total mass density derived from CHAMP. J Geophys Res 110:A04301. http://doi:10.1029/2004JA010741
Liu H, Lühr H, Watanabe S (2007) Climatology of the equatorial thermospheric mass density anomaly. J Geophys Res 112:A05305. http://doi:10.1029/2006JA012199
Liu H, Lühr H, Watanabe S, Köhler W, Henize V, Visser P (2006) Zonal winds in the equatorial upper thermosphere: decomposing the solar flux, geomagnetic activity, and seasonal dependencies. J Geophys Res 111:A07307. http://doi:10.1029/2005JA011415
Liu H, Watanabe S, Kondo T (2009a) Fast thermospheric wind jet at the Earth’s dip equator. Geophys Res Lett 36:L08103. http://doi:10.1029/2009037377
Liu H, Yamamoto M, Lühr H (2009b) Wave-4 pattern of the equatorial mass density anomaly- A thermospheric signature of tropical deep convection. Geophys Res Lett 36:L18104. http://doi:10.1029/2009GL039865
Lühr H, Maus S (2006) Direct observation of the F region dynamo currents and the spatial structure of the EEJ by CHAMP. Geophys Res Lett 33:L24102. http://doi:10.1029/2006GL028374
Lühr H, Rother M, Maus S, Mai W, Cooke D (2003) The diamagnetic effect of the equatorial Appleton anomaly: its characteristics and impact on geomagnetic field modelling. Geophys Res Lett 30(17):1906. http://doi:10.1029/2003GL017407
Lühr H, Rother M, Köhler W, Ritter P, Grunwaldt L (2004) Thermospheric up-welling in the cusp region, evidence from CHAMP observations. Geophys Res Lett 31:L06805. http://doi:10.1029/2003GL019314
Maeda H, Iyemori T, Araki T, Kamei T (1982) New evidence of a meridional current system in the equatorial ionosphere. Geophys Res Lett 9:337–340
Menvielle M, Marchaudon A (2007) Geomagnetic indices in solar-terrestrial physics and space weather, Space weather, research toward applications in Europe. In: Lilensten J (ed) Astrophysics and space science library. Springer, Berlin, pp 277–288
Müller S, Lühr H, Rentz S (2009) Solar and magnetospheric forcing of the low latitude thermospheric mass density as observed by CHAMP. Ann Geophys 27:2087–2099
Park J, Lühr H, Min KW (2010) Neutral density depletions associated with equatorial plasma bubbles as observed by the CHAMP satellite. J Atmos Solar-Terr Phys 72:157–163. http://doi:10.1016/j.jastp.2009.11.003
Prölss GW (1997) Magnetic storm associated perturbations of the upper atmosphere. In: Tsurutani BT, Gonzale WD, Kamide Y, Arballo JK (eds) Magnetic storms. Geophysical monograph series, vol 98. AGU, Washington, DC, p 227
Reigber C, Lühr H, Schwintzer P (2002) CHAMP mission status. Adv Space Res 30(2):129–134
Rentz S, Lühr H (2008) Climatology of the cusp-related thermospheric mass density anomaly, as derived from CHAMP observations. Ann Geophys 26:2807–2823
Rishbeth H (1971) The F-layer dynamo. Planet Space Sci 19:263–267
Rishbeth H, Müller-Wodarg ICF (2006) Why is there more ionosphere in January than in July? The annual asymmetry of the F-layer. Ann Geophys 24:3293–3311
Stolle C, Lühr H, Rother M, Balasis G (2006) Magnetic signatures of equatorial spread-F, as observed by the CHAMP satellite. J Geophys Res 111:A02304. http://doi:10.1029/2005JA011184
Trinks H, von Zahn U (1975) The ESRO4 gas analyzer. Rev Sci Instrum 46:213–217
Acknowledgements
We thank Claudia Stolle and Stefan Maus for fruitful discussions about the ionosphere–thermosphere results presented here. We also thank W. Köhler for processing the CHAMP accelerometer data. The CHAMP mission is sponsored by the Space Agency of the German Aerospace Center (DLR) through funds of the Federal Ministry of Economics and Technology, following a decision of the German Federal Parliament (grant code 50EE0944). The data retrieval and operation of the CHAMP satellite by the German Space Operations Center (GSOC) is acknowledged.
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Lühr, H., Liu, H., Park, J., Müller, S. (2011). New Aspects of the Coupling Between Thermosphere and Ionosphere, with Special regards to CHAMP Mission Results. In: Abdu, M., Pancheva, D. (eds) Aeronomy of the Earth's Atmosphere and Ionosphere. IAGA Special Sopron Book Series, vol 2. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-0326-1_22
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