Introduction to Special Issue on “Long‐Term Changes and Trends in the Middle and Upper Atmosphere”

Yue, Jia; Li, Tao; Qian, Liying; Laštovička, Jan; Zhang, Shun‐Rong

doi:10.1029/2019ja027462

Cited by 4 publications

(4 citation statements)

References 33 publications

(42 reference statements)

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“…Recently, Laštovička (2017) updated a review of progress in long‐term trends in the upper atmosphere. Yue et al (2019) reported the latest results on long‐term variations in the mesosphere and thermosphere. It appears that the long‐term temperature trends as well as its solar responses in the mesosphere are not uniform in magnitude but mostly agree in sign with the negative temperature trend and the positive solar response.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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“…Observational and simulation studies have revealed that the global mean temperature trend is cooling in the mesosphere and lower thermosphere (MLT) (Beig et al, 2003;Laštovička et al, 2006;Yue et al, 2019b;Laštovička, 2023). The cooling trends observed in the MLT region are mainly caused by the increasing anthropogenic greenhouse gases such as carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

Trends of the high latitude mesosphere temperature and mesopause revealed by SABER

Liu,

Xu,

Yue

et al. 2024

Preprint

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Abstract. The temperature trend in the mesosphere and lower thermosphere (MLT) region can be regarded as an indicator of climate change. Using temperature profiles measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument during 2002–2023 and binning them based on yaw cycle, we get continuous dataset with wide local time coverage at 50° S–80° N or 80° S–50° N. The seasonal change of temperature, caused by the forward drift of SABER yaw cycle, is removed by using the climatological temperature of MSIS2.0. The corrected temperature without any waves and is regarded as the mean temperature. At 50° S–50° N, the cooling trends of the mean temperature are significant in the MLT region and are in agreement with previous studies. The novel finding is that the cooling trends of ≥2 K/decade exhibit seasonal symmetric and reach peaks of ≥6 K/decade at highest latitudes around the summer solstice. Moreover, there are warming trends of 1–2.5 K/decade at pressure height range of 10-2–10-3 hPa, specifically at latitudes higher than 55° N in October and December and at latitudes higher than 55° S in April and August. The mesopause temperature (height) in the northern summer polar region is colder (lower) than that in the southern counterpart by ~5–11 K (~1 km) over the past 22 years. The trends of the mesopause temperature are dependent on latitudes and months. But they are negative at most latitudes and reach larger magnitudes at highest latitudes. These results indicate that the temperature in high latitude MLT region is more sensitive to dynamic changes.

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“…Here the long-term variations mean the linear term or linear change in a regression model and on a timescale longer than one solar cycle in the middle and upper atmosphere. The long-term variations of the middle and upper atmosphere have received attention due to greenhouse-gas-driven anthropogenic climate change and its influences on atmospheric drag and thus our space vehicles (Beig et al, 2003(Beig et al, , 2008Laštovička, 2017;Yue et al, 2019b;Mlynczak et al, 2022;Zhang et al, 2023). The intraannual variations mainly include annual (AO), semi-annual (SAO), and ter-annual (TAO) oscillations.…”

Section: Introductionmentioning

confidence: 99%

Variations in global zonal wind from 18 to 100 km due to solar activity and the quasi-biennial oscillation and El Niño–Southern Oscillation during 2002–2019

Liu¹,

Xu²,

Yue³

et al. 2023

Atmos. Chem. Phys.

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Abstract. Variations of global wind are important in changing the atmospheric structure and circulation, in coupling of atmospheric layers, and in influencing the wave propagations. Due to the difficulty of directly measuring zonal wind from the stratosphere to the lower thermosphere, we derived a global balance wind (BU) dataset from 50∘ S to 50∘ N and during 2002–2019 using the gradient wind theory and SABER temperatures and modified by meteor radar observations at the Equator. The dataset captures the main feature of global monthly mean zonal wind and can be used to study the variations (i.e., annual, semi-annual, ter-annual, and linear) of zonal wind and the responses of zonal wind to quasi-biennial oscillation (QBO), El Niño–Southern Oscillation (ENSO), and solar activity (F10.7). The same procedure is performed on the MERRA-2 zonal wind (MerU) to validate BU and its responses below 70 km. The annual, semi-annual, and ter-annual oscillations of BU and MerU have similar amplitudes and phases. The semi-annual oscillation of BU has peaks around 80 km, which are stronger in the southern tropical region and coincide with previous satellite observations. As the increasing of the values representing QBO wind, both values of representing BU and MerU (short for BU and MerU) change from increasing to decreasing with the increasing height and extend from the Equator to higher latitudes. Both BU and MerU increase with the increasing of the values of multivariate ENSO index (MEI) and decrease with increasing F10.7 in the southern stratospheric polar jet region below 70 km. The responses of winds to ENSO and F10.7 exhibit hemispheric asymmetry and are more significant in the southern polar jet region. While above 70 km, BU increases with the increasing of MEI and F10.7. The negative linear changes of BU at 50∘ N are absent in MerU during October–January. The discussions on the possible influences of the temporal intervals and sudden stratospheric warmings (SSWs) on the variations and responses of BU illustrate the following: (1) the seasonal variations and the responses to QBO are almost independent on the temporal intervals selected; (2) the responses to ENSO and F10.7 are robust but slightly depend on the temporal intervals; (3) the linear changes of both BU and MerU depend strongly on the temporal intervals; (4) SSWs affect the magnitudes but do not affect the hemispheric asymmetry of the variations and responses of BU at least in the monthly mean sense. The variations and responses of global zonal wind to various factors are based on BU, which is derived from observations, and thus provide a good complement to model studies and ground-based observations.

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Introduction to Special Issue on “Long‐Term Changes and Trends in the Middle and Upper Atmosphere”

Cited by 4 publications

References 33 publications

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

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

Trends of the high latitude mesosphere temperature and mesopause revealed by SABER

Variations in global zonal wind from 18 to 100 km due to solar activity and the quasi-biennial oscillation and El Niño–Southern Oscillation during 2002–2019

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