The importance of geomagnetic field changes versus rising CO2 levels for long-term change in the upper atmosphere

Journal of Space Weather and Space Climate

Ingrid Cnossen¹ 

[1] British Antarctic Survey, High Cross, Madingley Road,Cambridge,CB3 0ET,United Kingdom

关键词: global change;    modeling;    thermosphere;    ionosphere;    space climate;   

Others  :  800619
DOI  :  doi:10.1051/swsc/2014016

 received in 2013-10-30, accepted in 2014-05-07,  发布年份 2014

【 摘 要 】

The Earth’s upper atmosphere has shown signs of cooling and contraction over the past decades. This is generally attributed to the increasing level of atmospheric CO2, a coolant in the upper atmosphere. However, especially the charged part of the upper atmosphere, the ionosphere, also responds to the Earth’s magnetic field, which has been weakening considerably over the past century, as well as changing in structure. The relative importance of the changing geomagnetic field compared to enhanced CO2 levels for long-term change in the upper atmosphere is still a matter of debate. Here we present a quantitative comparison of the effects of the increase in CO2 concentration and changes in the magnetic field from 1908 to 2008, based on simulations with the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). This demonstrates that magnetic field changes contribute at least as much as the increase in CO2 concentration to changes in the height of the maximum electron density in the ionosphere, and much more to changes in the maximum electron density itself and to low-/mid-latitude ionospheric currents. Changes in the magnetic field even contribute to cooling of the thermosphere at ~300 km altitude, although the increase in CO2 concentration is still the dominant factor here. Both processes are roughly equally important for long-term changes in ion temperature.

【 授权许可】

   
© I. Cnossen, Published by EDP Sciences 2014

【 图 表 】

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

【 参考文献 】

• [1]Akmaev, R.A., On estimation and attribution of long-term temperature trends in the thermosphere, J. Geophys. Res., 117, A09321, 2012.
• [2]Akmaev, R.A., V.I. Fomichev, and X. Zhu, Impact of middle-atmospheric composition changes on greenhouse cooling in the upper atmosphere, J. Atmos. Sol. Terr. Phys., 68 (17), 1879–1889, 2006.
• [3]Bremer, J., Ionospheric trends in mid-latitudes as a possible indicator of the atmospheric greenhouse effect, J. Atmos. Terr. Phys., 54 (11–12), 1505–1511, 1992.
• [4]Bremer, J., Trends in the ionospheric E and F regions over Europe, Ann. Geophys., 16, 986–996, 1998.
• [5]Bremer, J., Long-term trends in the ionospheric E and F1 regions, Ann. Geophys., 26, 1189–1197, 2008.
• [6]Bremer, J., T. Damboldt, J. Mielich, and P. Suessmann, Comparing long-term trends in the ionospheric F2-region with two different methods, J. Atmos. Sol. Terr. Phys., 77, 174–185, 2012.
• [7]Clilverd, M.A., T.D.G. Clark, E. Clarke, H. Rishbeth, and T. Ulich, The causes of long-term changes in the aa index, J. Geophys. Res., 107 (A12), 14–41, 2002.
• [8]Cnossen, I., Climate change in the upper atmosphere. In: G., Liu, Editor. Greenhouse gases-emission, measurement and management, InTech, pp. 315–336, 2012.
• [9]Cnossen, I., and A.D. Richmond, Modelling the effects of changes in the Earth’s magnetic field from 1957 to 1997 on the ionospheric hmF2 and foF2 parameters, J. Atmos. Sol. Terr. Phys., 70, 1512–1524, 2008.
• [10]Cnossen, I., and A.D. Richmond, How changes in the tilt angle of the geomagnetic dipole affect the coupled magnetosphere-ionosphere-thermosphere system, J. Geophys. Res., 117, A10317, DOI: 10.1029/2012JA018056, 2012.
• [11]Cnossen, I., and A.D. Richmond, Changes in the Earth’s magnetic field over the past century: Effects on the ionosphere-thermosphere system and solar quiet (Sq) magnetic variation, J. Geophys. Res., 118, 849–858, DOI: 10.1029/2012JA018447, 2013.
• [12]Cnossen, I., A.D. Richmond, M. Wiltberger, W. Wang, and P. Schmitt, The response of the coupled magnetosphere-ionosphere-thermosphere system to a 25% reduction in the dipole moment of the Earth’s magnetic field, J. Geophys. Res., 116, A12304, DOI: 10.1029/2011JA017063, 2011.
• [13]Cnossen, I., A.D. Richmond, and M. Wiltberger, The dependence of the coupled magnetosphere-ionosphere-thermosphere system on the Earth’s magnetic dipole moment, J. Geophys. Res., 117, A05302, DOI: 10.1029/2012JA017555, 2012.
• [14]De Haro Barbas, B.F., A.G. Elias, I. Cnossen, and M. Zossi de Artigas, Long-term changes in solar quiet (Sq) geomagnetic variations related to Earth’s magnetic field secular variation, J. Geophys. Res., 118, 3712–3718, DOI: 10.1002/jgra.50352, 2013.
• [15]Donaldson, J.K., T.J. Wellman, and W.L. Oliver, Long-term change in thermospheric temperature above Saint Santin, J. Geophys. Res., 115, A11305, 2010.
• [16]Doumbia, V., A. Maute, and A.D. Richmond, Simulation of equatorial electrojet magnetic effects with the thermosphere-ionosphere-electrodynamics general circulation model, J. Geophys. Res., 112, A09309, 2007.
• [17]Elias, A.G., and N. Ortiz de Adler, Earth magnetic field and geomagnetic activity effects on long-term trends in the F2 layer at mid-high latitudes, J. Atmos. Sol. Terr. Phys., 68, 1871–1878, 2006.
• [18]Elias, A.G., M. Zossi de Artigas, and B.F. de Haro Barbas, Trends in the solar quiet geomagnetic field variation linked to the Earth’s magnetic field secular variation and increasing concentrations of greenhouse gases, J. Geophys. Res., 115, A08316, 2010.
• [19]Emmert, J.T., J.M. Picone, J.L. Lean, and S.H. Knowles, Global change in the thermosphere: Compelling evidence of a secular decrease in density, J. Geophys. Res., 109, A02301, 2004.
• [20]Emmert, J.T., and J.M. Picone, Statistical uncertainty of 1967–2005 thermospheric density trends derived from orbital drag, J. Geophys. Res., 116, A00H09, 2011.
• [21]Finlay, C.C., S. Maus, C.D. Beggan, et al., International Geomagnetic Reference Field: the eleventh generation, Geophys. J. Int., 183, 1216–1230, 2010. [NASA ADS]
• [22]Hagan, M.E., and J.M. Forbes, Migrating and nonmigrating diurnal tides in the middle and upper atmosphere excited by tropospheric latent heat release, J. Geophys. Res., 107 (D24), 4754, DOI: 10.1029/2001JD001236, 2002.
• [23]Hagan, M.E., and J.M. Forbes, Migrating and nonmigrating semidiurnal tides in the upper atmosphere excited by tropospheric latent heat release, J. Geophys. Res., 108, 1062, DOI: 10.1029/2002JA009466, 2003.
• [24]Heelis, R.A., J.K. Lowell, and R.W. Spiro, A model of the high-latitude ionospheric convection pattern, J. Geophys. Res., 87, 6339–6345, 1982.
• [25]Jarvis, M.J., B. Jenkins, and G.A. Rodgers, Southern hemisphere observations of a long-term decrease in F region altitude and thermospheric wind providing possible evidence for global thermospheric cooling, J. Geophys. Res., 103, 20774–20787, 1998.
• [26]Keating, G.M., R.H. Tolson, and M.S. Bradford, Evidence of long term global decline in the Earth’s thermospheric densities apparently related to anthropogenic effects, Geophys. Res. Lett., 27, 1523–1526, 2000.
• [27]Laštovička, J., S.C. Solomon, and L. Qian, Trends in the neutral and ionized upper atmosphere, Space Sci. Rev., 168, 113–145, 2012.
• [28]Maeda, S., T.J. Fuller-Rowell, and D.S. Evans, Heat budget of the thermosphere and temperature variations during the recovery phase of a geomagnetic storm, J. Geophys. Res., 97, 14947–14957, 1992.
• [29]Oliver, W.L., S.-R. Zhang, and L.P. Goncharenko, Is thermospheric global cooling caused by gravity waves? J. Geophys. Res., 118, 3898–3908, 2013.
• [30]Qian, L., A.G. Burns, S.C. Solomon, and R.G. Roble, The effect of carbon dioxide cooling on trends in the F2-layer ionosphere, J. Atmos. Sol. Terr. Phys., 71, 1592–1601, 2009.
• [31]Qian, L., A.G. Burns, B.A. Emery, B. Foster, G. Lu, A. Maute, A.D. Richmond, R.G. Roble, S.C. Solomon, and W. Wang, The NCAR TIE-GCM: A community model of the coupled thermosphere/ionosphere system. In: J.D., Huba, R.W. Schunk, and G. Khazanov, Editors. Modeling the Ionosphere-Thermosphere System, vol. 201, p. 73–83, Am. Geophys. Union monograph, ISBN 978-0-87590-491-7, DOI: 10.1002/9781118704417.ch7, 2014.
• [32]Richmond, A.D., E.C. Ridley, and R.G. Roble, A thermosphere/ionosphere general circulation model with coupled electrodynamics, Geophys. Res. Lett., 19 (6), 601–604, 1992.
• [33]Richmond, A.D., and A. Maute, Ionospheric electrodynamics modeling. In: J.D., Huba, R.W. Schunk, and G. Khazanov, Editors. Modeling the Ionosphere-Thermosphere System, Am. Geophys. Union monograph, vol. 201, p. 57–71, ISBN 978-0-87590-491-7, DOI: 10.1002/9781118704417.ch6, 2014.
• [34]Rishbeth, H., A greenhouse effect in the ionosphere, Planet. Space Sci., 38 (7), 945–948, 1990.
• [35]Rishbeth, H., and R.G. Roble, Cooling of the upper atmosphere by enhanced greenhouse gases–modelling of thermospheric and ionospheric effects, Planet. Space Sci., 40 (7), 1011–1026, 1992.
• [36]Roble, R.G., and R.E. Dickinson, How will changes in carbon dioxide and methane modify the mean structure of the mesosphere and thermosphere, Geophys. Res. Lett., 16 (12), 1441–1444, 1989.
• [37]Roble, R.G., E.C. Ridley, A.D. Richmond, and R.E. Dickinson, A coupled thermosphere/ionosphere general circulation model, Geophys. Res. Lett., 15 (12), 1325–1328, 1988.
• [38]Sharma, R.D., and R.G. Roble, Cooling mechanisms of the planetary thermospheres: they key role of O atom vibrational excitation of CO2 and NO, Chem. Phys. Chem., 3, 841–843, 2002.
• [39]Stamper, R., M. Lockwood, M.N. Wild, and T.D.G. Clark, Solar causes of the long-term increase in geomagnetic activity, J. Geophys. Res., 104 (A12), 28325–28342, 1999.
• [40]Torta, J.M., L.R. Gaya-Piqué, J.J. Curto, and D. Altadill, An inspection of the long-term behaviour of the range of the daily geomagnetic field variation from comprehensive modelling, J. Atmos. Sol. Terr. Phys., 71, 1497–1510, 2009.
• [41]Ulich, T., and E. Turunen, Evidence for long-term cooling of the upper atmosphere in ionosonde data, Geophys. Res. Lett., 24, 1103–1106, 1997.
• [42]Upadhyay, H.O., and K.K. Mahajan, Atmospheric greenhouse effect and ionospheric trends, Geophys. Res. Lett., 25, 3375–3378, 1998.
• [43]Yue, X., L. Liu, W. Wan, Y. Wei, Z. Ren, Modeling the effects of secular variation of geomagnetic field orientation on the ionospheric long term trend over the past century, J. Geophys. Res., 113, A10301, 2008.
• [44]Zhang, S.-R., J.M. Holt, Long-term ionospheric cooling: dependency on local time, season, solar activity and geomagnetic activity, J. Geophys. Res., 118, 3719–3730, DOI: 10.1002/jgra.50306, 2013.
• [45]Zhang, S.-R., J.M. Holt, J. Kurdzo, Millstone Hill ISR observations of upper atmospheric long-term changes: Height dependency, J. Geophys. Res., 116, A00H05, 2011.