Gravity waves above the northern Atlantic and Europe during streamer events using Aeolus

<p>Information about the energy density of gravity waves (GWs) is crucial for improving atmosphere models. So far, most space-based studies report the potential energy, <span class="inline-formula"><i>E</i><sub>pot</sub></span>, of GWs, as temperat...

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Bibliographic Details
Main Authors: S. Wüst, L. Küchelbacher, F. Trinkl, M. Bittner
Format: Article
Language:English
Published: Copernicus Publications 2025-04-01
Series:Atmospheric Measurement Techniques
Online Access:https://amt.copernicus.org/articles/18/1591/2025/amt-18-1591-2025.pdf
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Summary:<p>Information about the energy density of gravity waves (GWs) is crucial for improving atmosphere models. So far, most space-based studies report the potential energy, <span class="inline-formula"><i>E</i><sub>pot</sub></span>, of GWs, as temperature measurements from satellites are more common.</p> <p>We use Aeolus wind data to derive the kinetic energy density, <span class="inline-formula"><i>E</i><sub>kin</sub></span>, of GWs above the northern Atlantic and Europe. Assuming perfect instrument performance, this would be a lower limit for the kinetic energy density, as Aeolus only measures the horizontal line-of-sight wind. Aeolus, the European Space Agency's (ESA's) fourth Earth Explorer Mission, was the first Doppler wind lidar in space and measured vertical profiles of the horizontal line-of-sight wind from the ground to an altitude of <span class="inline-formula">∼</span> 20–30 km between 2018 and 2023. With a vertical resolution of 0.25–2 km, Aeolus measurements are in principle well suited for the analysis of GWs. However, the data quality is a challenge for such analyses, as the error in the data is in the range of typical GW amplitudes in the troposphere and stratosphere.</p> <p>In this study, we derive daily resolved time series of <span class="inline-formula"><i>E</i><sub>kin</sub></span> before, during, and after two streamer events above the northern Atlantic and Europe. Streamers are large-scale tongue-like structures of meridionally deflected air masses, which are caused by enhanced planetary wave activity. They are linked to vertical shear of horizontal wind and a pressure system, two possible GW generation mechanisms. We find that there is a temporal coincidence between the enhanced daily averaged <span class="inline-formula"><i>E</i><sub>kin</sub></span> and occurrence of the streamer events, which we identified in total column ozone measurements. The derivation of GW signals based on Aeolus data is possible, however: we collected about 100 profiles to statistically reduce the uncertainty in the daily averaged <span class="inline-formula"><i>E</i><sub>kin</sub></span>. Compared to non-satellite measurements, those daily averaged values are at the upper border.</p>
ISSN:1867-1381
1867-8548