Long‐Term Trends and Solar Responses of the Mesopause Temperatures Observed by SABER During the 2002–2019 Period

Abstract

The global distribution and variations of the monthly mesopause temperature are presented during 2002–2019 covering the latitudes of 83°S to 83°N based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations. To investigate the long‐term trend and solar response of the mesopause temperature, a three‐component harmonic fit is first applied to remove the seasonal variation from the monthly temperature data series. Then a multiple linear regression model is performed to residual temperatures versus constant, linear trend, solar activity, and geomagnetic activity terms. In this study, the mesopause temperature shows a cooling trend through all latitudes ranging from ~0 to −0.14 K/year with a mean of −0.075 ± 0.043 K/year. The cooling trends in the Southern Hemisphere are stronger than those in the Northern Hemisphere. For high latitudes (60–80°), significant negative trends can be observed during nonsummertime, while no significant trends are found for summertime. The mesopause temperature shows apparent positive responses to solar activity through all latitudes ranging from 3.03 to 4.80 K per 100 solar flux units (sfu) with a mean of 3.99 ± 0.49 K per 100 sfu, which is more significant and stable in the Northern Hemisphere. There is a pronounced drop for mesopause height at polar latitudes, which reflects the shrinking effect at lower altitudes mainly caused by greenhouse gas cooling. We show that the length of the time interval analyzed strongly influences the results. Our results, obtained from 18‐year SABER observations, are expected to be a robust measure of the mesopause temperature variability.

Solar Cycle and Long‐Term Trends in the Observed Peak of the Meteor Altitude Distributions by Meteor Radars

“…At high latitudes, the long-term trends in peak altitude diminish. This contrasts with reports that broadly indicate the strongest trends in temperature, mesospheric O 3 , and water vapor occur at high latitudes (Dawkins et al, 2016;Hervig et al, 2016;Zhao et al, 2020), albeit all with larger uncertainties. This behavior, and the hemispheric asymmetry in linear trend responses reported here and in Qian et al (2017), Sharma et al (2018), and Das (2021) suggest a role for dynamics, particularly at high latitudes.…”

“…This is consistent with the work of Yuan et al (2019), Bailey et al (2021), Mlynczak et al (2022), and modeling studies which have demonstrated hydrostatic contraction of the middle and upper atmosphere in response to increasing GHG emissions (Roble and Dickinson, 1989;Akmaev et al, 2006;Lübken & Berger, 2011). The linear response in peak altitude was relatively small at low latitudes and increased toward the mid-latitudes, consistent with work by Zhao et al (2020Zhao et al ( , 2021.…”

“…Hemispheric asymmetry in the temperature response was also observed by Zhao et al (2020) and Das (2021) using SABER measurements. Unfortunately, long-term meteor radar data for a low-latitude northern hemisphere location is unavailable, but Sharma et al (2018), using SABER overpass observations of two low-latitude locations (24.6°N, 21.1°S), were able to demonstrate that the southern hemisphere location had a cooling trend twice that of the northern hemisphere one (−0.14 vs. −0.07 K yr −1 ).…”

The influence of solar variability on Atlantic basin tropical cyclones: a 10-year study

“…A model proposed by Matthes, Langematz [9] suggested that the solar influence on the mesopause region to be minimal. This knowledge is supported by numerous studies conducted prior and subsequent to it [10][11][12][13]. In a recent study, simulations presented by Solomon, Liu [14] has demonstrated that low solar activity periods show greater impact on long-term global changes in the thermosphere and ionosphere as compared to high solar activity periods.…”

Mesospheric and Upper Stratospheric Temperatures From OMPS‐LP

“…Recently, Zhao et al. (2020) detected a cooling trend of ∼0 to −0.14 K/decade at all latitudes using the annual mean temperatures from Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) instrument from 2002 to 2019. Li et al.…”