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
<p>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 gl...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-06-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/6145/2023/acp-23-6145-2023.pdf |
| Summary: | <p>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<span class="inline-formula"><sup>∘</sup></span> S to 50<span class="inline-formula"><sup>∘</sup></span> 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 (<span class="inline-formula"><i>F</i><sub>10.7</sub></span>). 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 <span class="inline-formula"><i>F</i><sub>10.7</sub></span> in the southern stratospheric polar jet region below 70 km. The responses of winds to ENSO and <span class="inline-formula"><i>F</i><sub>10.7</sub></span> 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
<span class="inline-formula"><i>F</i><sub>10.7</sub></span>. The negative linear changes of BU at 50<span class="inline-formula"><sup>∘</sup></span> 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 <span class="inline-formula"><i>F</i><sub>10.7</sub></span> 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.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |