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Keywords:

  • mesosphere;
  • seasonal variations;
  • subtropcial latitudes

[1] We present here a detailed investigation of the mesospheric temperature structure over Taiwan, a subtropical location, using 9 years of observations (March 2002 to October 2010) by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The mesopause (MP) is always found to be located at a higher level with a mean altitude of 98.2 ± 1.8 km and mean temperature of 165.0 ± 5.8 K. The climatological study shows that MP is lower and warmer during summer and higher and cooler during winter, which is different from the midlatitudes and high latitudes as well as from low latitudes. The temperatures of the mesospheric temperature inversions (MTI) and secondary minimum (SM), on the other hand, are lower during summer and higher during winter, and their altitudes do not show any annual variation. It is found that the thermal structure over Taiwan undergoes a phase shift between 89 and 95 km, and above this region it is in phase with the solar flux. Since MP is always above these altitudes, it shows a seasonal variation that is in phase with the solar energy inputs, and the temperatures below (that of MTI and SM) show the opposite seasonal variation caused by mesospheric adiabatic cooling and warming processes.