Global structure and long‐term variations of zonal mean temperature observed by TIMED/SABER

Abstract

[1] In this paper, we present a method of extracting zonal mean temperature and tides from TIMED/SABER satellite and discuss the features of the zonal mean temperature. The global temperature structure is presented, and the mean variations at each latitude and altitude are decomposed into semiannual (SAO), annual (AO), and quasi-biennial (QBO) components. The SAO is strong in the tropical upper stratosphere, mesosphere, and lower thermosphere. The SAO phase (measured by the time of the maximum) is at the equinox at 85 km and at solstice at 75 km. The amplitude is large compared to the annual mean temperature structure, which leads to a mesospheric inversion layer (MIL) in the zonal mean temperature around the equator at equinox. The AO is most evident at middle latitudes and displays a clear hemispheric asymmetry at solstices. The QBO in temperature is strongest in the tropical lower stratosphere; its period there is 26.6 months. There are also weak QBO signals near the mesopause and throughout the middle atmosphere at midlatitudes. The analysis of longer-term variations of the zonal mean temperature, probably affected by the solar cycle but also containing any other trends, indicates that in most regions, the zonal mean temperature decreases during the period of 5 years and is positively correlated with the solar radiation. These results use version 1.06 of the SABER temperature data, which have some known biases in the vicinity of the mesopause.

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

“…phenomenon that stronger MIL amplitudes are at spring equinox than at autumn equinox can be explained by the seasonal asymmetries at both 75 and 85 km described in Section 4. This is not pointed out in previous studies (e.g., [25,47]). …”

“…The phenomenon that stronger MIL amplitudes are at spring equinox than at autumn equinox can be explained by the seasonal asymmetries at both 75 and 85 km described in Section 4. This is not pointed out in previous studies (e.g., [25,47] phenomenon that stronger MIL amplitudes are at spring equinox than at autumn equinox can be explained by the seasonal asymmetries at both 75 and 85 km described in Section 4. This is not pointed out in previous studies (e.g., [25,47]).…”

“…In order to eliminate tides and planetary waves so as to obtain more accurate estimates of the zonal mean temperature, a 60-day sliding window with a one-day step is used to deal with the raw data [25]. Since 52 • pole-ward observations only exist on alternate yaw cycles, the central latitudes of this paper are extended from 50 • S to 50 • N, with a resolution of 5 • .…”

“…Atmospheric variations can be decomposed into several components, including mean waves, tides, and planetary waves [25,35]. In order to eliminate tides and planetary waves so as to obtain more accurate estimates of the zonal mean temperature, a 60-day sliding window with a one-day step is used to deal with the raw data [25].…”

Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

“…From the satellite-based Wind Imaging Interferometer (WINDII) and the ground-based airglow measurement instruments derived zonal mean temperature, Shepherd et al (2004) investigated the characteristics and properties of the SAO and AnO over low and mid latitude sites. Xu et al (2007) studied seasonal, altitudinal and latitudinal variability of the SAO, AnO and quasi-biennial oscillation (QBO) with the help of zonal mean temperature data of Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the ThermosphereIonosphere-Mesosphere Energetics and Dynamics (TIMED) satellite in the stratosphere and mesosphere region. Zhao et al (2007) studied the properties of the SAO and AnO using O 2 (0-1) and OH (6-2) emissions with the help of airglow imager instrument from a low latitude station, Maui, USA (20.8 • N).…”