Mesopause structure from Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)/Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) observations

Abstract

[1] Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)/ Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) temperature observations are used to study the global structure and variability of the mesopause altitude and temperature. There are two distinctly different mesopause altitude levels: the higher level at 95-100 km and the lower level below $86 km. The mesopause of the middle-and high-latitude regions is at the lower altitude in the summer hemisphere for about 120 days around summer solstice and is at the higher altitude during other seasons. At the equator the mesopause is at the higher altitude for all seasons. In addition to the seasonal variation in middle and high latitudes, the mesopause altitude and temperature undergo modulation by diurnal and semidiurnal tides at all latitudes. The mesopause is about 1 km higher at most latitudes and 6-9 K warmer at middle to high latitudes around December solstice than it is around June solstice. These can also be interpreted as hemispheric asymmetry between mesopause altitude and temperature at solstice. Possible causes of the asymmetry as related to solar forcing and gravity wave forcing are discussed.

Properties of the Long-Term Oscillations in the Middle Atmosphere Based on Observations from TIMED/SABER Instrument and FPI over Kelan

“…It is obvious in Figure 1 that the AO and SAO are the most prominent zonal mean oscillations in the middle atmosphere, and their morphologies are in agreement with previous studies (e.g., [3,4]). In addition, the three-year oscillation signal, which is significant as well as the QBO and SAO, especially at around 45 km over the equatorial region, has attracted our attention.…”

Global Dynamics of the MLT

“…PMC altitudes are sensitive to temperature but also to other variable fields such as water vapor and vertical wind. Xu et al (2007a) found similar differences in the mesopause height determined from SABER temperature measurements. Hervig and Siskind (2006) found larger differences in mean summer temperature at 65-70°in HALOE data; the SH was warmer by 3-6 K throughout the mesosphere.…”

“…1). However, in the summer high latitudes, the mesopause temperature is much lower, and its altitude is lower (von Zahn et al 1996;Xu et al 2007a). The global low temperature at 95-100 km is due to the radiative balance there.…”

“…Observations (e.g., Huang et al 2006;Xu et al 2007a) also indicate that there is an interannual variation in the zonally averaged temperature in the MLT that is related to the quasi-biennial oscillation (QBO) in tropical lower stratospheric winds and temperature. The driving mechanism for this may be the same as that for the SAO in the MLT, see Sect.…”

A comparison of ground-based hydroxyl airglow temperatures with SABER/TIMED measurements over 23° N, India

“…Several space-borne instruments like the Microwave Limb Sounder (MLS) on the Aura satellite; Atmospheric Chemistry Experiment -Fourier Transform Spectrometer (ACE-FTS) on SciSat-1; Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) on Environmental Satellite (ENVISAT); Solar Occultation for Ice Experiment (SOFIE) on the AIM satellite; Optical, Spectroscopic, and Infrared Remote Imaging System (ORISIS) on the Odin satellite; the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) satellite instrument, and Sounding of the Atmosphere by Broadband Emission of Radiation (SABER) on-board the TIMED mission satellite have also contributed immensely to our knowledge of the temperature field of the MLT region (von Savigny et al, 2004;Scheer et al, 2006;Xu et al, 2007;Mulligan and Lowe, 2008;French and Mulligan, 2010;Sheese et al, 2011;García-Comas et al, 2012, 2014and references cited therein).…”