Location of Repository

Modelling of long-term trends in the middle and upper atmosphere.

By Ingrid Cnossen


From the 1950s/1960s to the present, long-term trends in temperature, density and winds in the middle and upper atmosphere, and in the height of the peak of the ionospheric F2 layer (hmF2) and its critical frequency (foF2) have been observed. These trends are usually attributed to increases in CO2 concentration that have occurred over the same time span, which cause a cooling and contraction of the middle and upper atmosphere. However, modelling studies generally predict smaller trends in temperature, larger trends in density, and more globally uniform trends in hmF2 and foF2 due to changes in CO2 concentration than have been observed. When additional changes in ozone concentration are accounted for, modelling results are in better agreement with observations, but so far this had only been studied up to ~150-200 km.\ud Here we used the Coupled Middle Atmosphere and Thermosphere model version 2 to study the combined effects of changes in CO2 and ozone concentration on the middle and upper atmosphere, including the ionosphere, from ~15-300 km. It was confirmed that changes in ozone concentration affect trends in temperature and density substantially until 200 km, and also effects above 200 km and on hmF2 were found. The results depended on the gravity wave parameterization used by the model, showing that dynamical factors can influence long-term trends. The Thermosphere-Ionosphere-Electrodynamics General Circulation Model was used to model the effects of changes in the Earth’s magnetic field on hmF2 and foF2. Substantial trends were found over South\ud America and the Atlantic Ocean, while other parts of the world were little affected.\ud Sensitivity analyses showed that the responses obtained with both models depend on geophysical conditions such as season and solar and geomagnetic activity. In general it can be concluded that long-term trends are probably caused by multiple coupled radiative and dynamical processes

Publisher: University of Leicester
Year: 2009
OAI identifier: oai:lra.le.ac.uk:2381/4533

Suggested articles



  1. (1980). A 3-dimensional time-dependent global model of the thermosphere.
  2. (1995). A 4-dimensional ozone climatology for UGAMP models.
  3. (1988). A coupled thermosphere ionosphere general circulation model.
  4. (1990). A greenhouse effect in the ionosphere?
  5. (2005). A long-term comparison of mesopause region wind measurements over Eastern and Central Europe.
  6. (2000). A model estimate of cooling in the mesosphere and lower thermosphere due to the CO2 increase over the last 3-4 decades.
  7. (1982). A model of the high-latitude ionospheric convection pattern.
  8. (2001). A new coupled middle atmosphere and thermosphere general circulation model: studies of dynamic, energetic and photochemical coupling in the middle and upper atmosphere. Dissertation/Thesis,
  9. (1966). A new method for the prediction of gas phase diffusion coefficient.
  10. (1982). A quasi one-dimensional model of the middle atmosphere circulation interacting with internal gravity waves.
  11. (2002). A study into the effect of the diurnal tide on the structure of the background mesosphere and thermosphere using the new coupled middle atmosphere and thermosphere (CMAT) general circulation model.
  12. (2006). A study into the effects of gravity wave activity on the diurnal tide and airglow emissions in the equatorial mesosphere and lower thermosphere using the Coupled Middle Atmosphere and Thermosphere (CMAT) general circulation model.
  13. (1992). A thermosphere-ionosphere general circulation model with coupled electrodynamics.
  14. (1994). A thermosphere-ionosphere-mesosphereelectrodynamics general circulation model (time-GCM): Equinox solar cycle minimum simulations (30-500 km).
  15. (1975). An improved phenomenological model of ionospheric density.
  16. (2000). An introduction to atmospheric physics.
  17. (2006). Applying artificial neural network to derive long-term foF2 trends in the Asia/Pacific sector from ionosonde observations.
  18. (2008). Atmospheric CO2 records from sites in the SIO air sampling network, in: Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis
  19. (1966). Atmospheric composition in the lower thermosphere.
  20. (1998). Atmospheric greenhouse effect and ionospheric trends.
  21. (2006). Calculated and observed climate change in the thermosphere, and a prediction for solar cycle 24.
  22. (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.
  23. (1990). Climate change and the middle atmosphere 1. The doubled CO2 climate.
  24. (1995). Climatic trends of the mid-latitude upper atmosphere and ionosphere.
  25. (1990). Collision integrals and high temperature transport properties for N-N,
  26. (1996). Combined mesosphere/thermosphere winds using WINDII and HRDI data from the Upper Atmosphere Research Satellite.
  27. (2002). Cooling mechanisms of the planetary thermospheres: The key role of O atom vibrational excitation of CO2 and NO.
  28. (1998). Cooling of the mesosphere and lower thermosphere due to doubling of CO2.
  29. (1992). Cooling of the upper atmosphere by enhanced greenhouse gases - modelling of thermospheric and ionospheric effects.
  30. (1993). Cooling of the upper atmosphere due to CO2 increases - a model study.
  31. (2005). Detection of a long-term decrease in thermospheric neutral density.
  32. (1995). Development of the new CCC/GCM longwave radiation model for extension into the middle atmosphere.
  33. (1997). Doppler-spread parameterization of gravity-wave momentum deposition in the middle atmosphere. Part 2: Broad and quasi monochromatic spectra, and implementation.
  34. (2004). Doubled CO2-induced cooling in the middle atmosphere: Photochemical analysis of the ozone radiative feedback.
  35. (2006). Earth magnetic field and geomagnetic activity effects on long-term trends in the F2 layer at mid-high latitudes.
  36. (2008). Emerging pattern of global change in the upper atmosphere and ionosphere.
  37. (2004). Empirical model of nitric oxide in the lower thermosphere.
  38. (1996). Empirical wind model for the upper, middle and lower atmosphere.
  39. (1995). Estimating the global ozone characteristics during the last 30 years.
  40. (1997). Evidence for long-term cooling of the upper atmosphere in ionosonde data.
  41. (2000). Evidence of long term global decline in the Earth’s thermospheric densities apparently related to anthropogenic effects.
  42. (1991). Extension of the MSIS thermosphere model into the middle and lower atmosphere.
  43. (2001). F2-layer parameters long-term trends at the Argentine Islands and Port Stanley stations.
  44. (2008). Geomagnetic and ionospheric data analysis over Antarctica: a contribution to the long term trends investigation.
  45. (2004). Global change in the thermosphere: compelling evidence of a secular decrease in density.
  46. (2006). Global change in the upper atmosphere.
  47. (2008). Global estimates of gravity wave momentum flux from High Resolution Dynamics Limb Sounder observations.
  48. (2006). Gravity wave climatology and trends in the mesosphere/lower thermosphere region deduced from low-frequency drift measurements 1984–2003 (52.1°N,
  49. (2003). Gravity wave dynamics and effects in the middle atmosphere.
  50. (1999). Gravity wave interactions with mesospheric planetary waves: A mechanism for penetration into the thermosphere-ionosphere system.
  51. (1984). Gravity wave saturation in the middle atmosphere: a review of theory and observations.
  52. (1998). How the thermospheric circulation affects the ionospheric F2-layer.
  53. (1989). How will changes in carbon-dioxide and methane modify the mean structure of the mesosphere and thermosphere?
  54. (2006). Impact of middle-atmospheric composition changes on greenhouse cooling in the upper atmosphere.
  55. (1998). Increased magnetic storm activity from 1868 to
  56. (2003). Influence of anthropogenic climate gas changes on the summer mesospheric/upper thermospheric meridional wind.
  57. (2001). International Reference Ionosphere
  58. (1961). Interplanetary magnetic field and the auroral zones.
  59. (1996). Ionospheric F-2 layer seasonal and semiannual variations.
  60. (1999). Ionospheric long-term trends for South American mid-latitudes.
  61. (2006). Ionospheric long-term trends: can the geomagnetic control and greenhouse hypotheses be reconciled?
  62. (1992). Ionospheric trends in midlatitudes as a possible indicator of the atmospheric greenhouse effect.
  63. (1999). Long term ionospheric trends over Ahmedabad.
  64. (2004). Long-term ionospheric trends based on ground-based ionosonde observations at Kokubunji,
  65. (2008). Long-term temperature trends in the ionosphere above Millstone Hill.
  66. (2006). Long-term trends and year-to-year variability of mid-latitude mesosphere/lower thermosphere winds.
  67. (2002). Long-term trends in foF2 over Grahamstown using neural networks.
  68. (2006). Long-term trends in foF2: A comparison of various methods.
  69. (1999). Long-term trends of the yearly mean temperature at heights from 25 to 110 km.
  70. (1998). Matrix parameterization of the 15 μm CO2 band cooling in the middle and upper atmosphere for variable CO2 concentration.
  71. (2002). Mean winds of the mesosphere and lower thermosphere at 52 degrees N in the period 1988-2000.
  72. (2007). Mesopause structure from Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)/Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) observations.
  73. (2003). Mesospheric carbon dioxide content as determined from the CRISTA-1 experimental data.
  74. (2002). Mesospheric temperature trends derived from ground-based LF phase-height observations at mid-latitudes: comparison with model simulations.
  75. (2008). Model simulations of global change in the ionosphere.
  76. (2008). Modelled effect of changes in the CO2 concentration on the middle and upper atmosphere: sensitivity to gravity wave parameterization.
  77. (2005). Modelling studies of possible coupling mechanisms between the upper and middle atmosphere. Dissertation/Thesis,
  78. (2008). Modelling the effects of changes in the Earth’s magnetic field from
  79. (1998). Non-local thermodynamic equilibrium in CO2 in the middle atmosphere. I. Input data and populations of the ν3 mode manifold states.
  80. (1982). Nonlinear theory of gravity waves: momentum deposition, generalized Rayleigh friction, and diffusion.
  81. (1995). On modelling migrating solar tides.
  82. (2005). On the role of solar and geomagnetic activity in long-term trends in the atmosphere-ionosphere system.
  83. (1990). Parameterization of accelerations and heat flux divergences produced by internal gravity waves in the middle atmosphere.
  84. (2000). Parameterization of gravity wave momentum deposition based on nonlinear wave interactions: basic formulation and sensitivity tests.
  85. (1993). Parameterization of the 15 μm CO2 band cooling in the middle atmosphere (15– 115 km).
  86. (1996). Planetary waves in the thermosphere-ionosphere system.
  87. (1961). Propagation of planetary-scale disturbances from the lower into the upper atmosphere.
  88. (1999). Propagation of the Arctic Oscillation from the stratosphere to the troposphere.
  89. (2007). Radar observations of long-term variability of mesosphere and lower thermosphere winds over
  90. (2003). Residual solar cycle influence on trends in ionospheric F2-layer peak height.
  91. (2003). Review of mesospheric temperature trends.
  92. (1990). Role of carbon-dioxide in cooling planetary thermospheres.
  93. (1990). Saturated and unsaturated spectra of gravity waves and scale-dependent diffusion.
  94. (1997). Solar cycle dependence and long-term trends in the wind field of the mesosphere/lower thermosphere.
  95. (1998). Southern hemisphere observations of a long-term decrease in F region altitude and thermospheric wind providing possible evidence for global thermospheric cooling.
  96. (1999). Spatial and seasonal variations of the foF2 long-term trends.
  97. (2002). Stratospheric connection to Nortern Hemisphere wintertime weather: Implications for prediction.
  98. (1999). Stratospheric ozone depletion: a review of concepts and history.
  99. (1980). Stratospheric sensitivity to perturbations in ozone and carbon-dioxide - Radiative and dynamical response.
  100. (2001). Stratospheric temperature trends: Observations and model simulations.
  101. (2001). Stratospheric water vapor increases over the past half-century.
  102. (1996). Temperature regime of the lower thermosphere from emission measurements during the last decades.
  103. (2005). The 10th-Generation International Geomagnetic Reference Field.
  104. (2001). The carbon cycle and atmospheric carbon dioxide, in:
  105. (1985). The effect of breaking gravity waves on the dynamics and chemical composition of the mesosphere and lower thermosphere.
  106. (1994). The heat budget and global change in the mesosphere. Dissertation/Thesis,
  107. (1995). The importance of dynamical feedbacks on doubled CO2-induced changes in the thermal structure of the mesosphere.
  108. (1983). The influence of gravity wave breaking on the general circulation of the middle atmosphere.
  109. (1997). The parameterization of gravity wave drag based on the nonlinear diffusion of wave spectra, in:
  110. (1982). The role of gravity wave induced drag and diffusion in the momentum budget of the mesosphere.
  111. (1991). The saturation of gravity waves in the middle atmosphere. Part II: development of Doppler-spread theory.
  112. (1992). The solar-terrestrial environment.
  113. (2000). The SOLAR2000 empirical solar irradiance model and forecast tool.
  114. (2002). The vertical and horizontal distribution of CO2 densities in the upper mesosphere and lower thermosphere as measured by CRISTA.
  115. (2003). Thermal effects of saturating gravity waves in the atmosphere.
  116. (1984). Thermospheric general circulation with coupled dynamics and composition.
  117. (2008). Thermospheric global average density trends, 1967-2007, derived from orbits of 5000 near-Earth objects.
  118. (2006). Three-dimensional GCM modelling of nitric oxide in the lower thermosphere.
  119. (1998). Trends in the ionospheric
  120. (2001). Trends in the thermosphere derived from global ionosonde observations.
  121. (1981). Turbulence and stress owing to gravity wave and tidal breakdown.
  122. (1995). Vertical evolution of gravity wave spectra and the parameterization of associated wave drag.
  123. (1999). Vibrational relaxation of NO(ν=1) by oxygen atoms.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.