Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses
Due to their increasing spatial resolution, numerical weather prediction (NWP) models and the associated analyses resolve a growing fraction of the gravity wave (GW) spectrum. However, it is unclear how well this “resolved” part of the spectrum truly compares to the actual atmospheric variability. I...
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ftdoajarticles:oai:doaj.org/article:e31d971934a5420c91e849f038e81263 2023-05-15T13:43:33+02:00 Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses A. Podglajen A. Hertzog R. Plougonven B. Legras 2020-08-01T00:00:00Z https://doi.org/10.5194/acp-20-9331-2020 https://doaj.org/article/e31d971934a5420c91e849f038e81263 EN eng Copernicus Publications https://acp.copernicus.org/articles/20/9331/2020/acp-20-9331-2020.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-20-9331-2020 1680-7316 1680-7324 https://doaj.org/article/e31d971934a5420c91e849f038e81263 Atmospheric Chemistry and Physics, Vol 20, Pp 9331-9350 (2020) Physics QC1-999 Chemistry QD1-999 article 2020 ftdoajarticles https://doi.org/10.5194/acp-20-9331-2020 2022-12-31T04:25:57Z Due to their increasing spatial resolution, numerical weather prediction (NWP) models and the associated analyses resolve a growing fraction of the gravity wave (GW) spectrum. However, it is unclear how well this “resolved” part of the spectrum truly compares to the actual atmospheric variability. In particular, the Lagrangian variability, relevant, for example, to atmospheric dispersion and to microphysical modeling in the upper troposphere–lower stratosphere (UTLS), has not yet been documented in recent products. To address this shortcoming, this paper presents an assessment of the GW spectrum as a function of the intrinsic (air parcel following) frequency in recent (re)analyses (ERA-Interim, ERA5, the ECMWF operational analysis and MERRA-2). Long-duration, quasi-Lagrangian balloon observations in the equatorial and Antarctic lower stratosphere are used as a reference for the atmospheric spectrum and are compared to synthetic balloon observations along trajectories calculated using the wind and temperature fields of the reanalyses. Overall, the reanalyses represent realistic features of the spectrum, notably the spectral gap between planetary and gravity waves and a peak in horizontal kinetic energy associated with inertial waves near the Coriolis frequency f in the polar region. In the tropics, they represent the slope of the spectrum at low frequency. However, the variability is generally underestimated even in the low-frequency portion of the spectrum. In particular, the near-inertial peak, although present in the reanalyses, has a reduced magnitude compared to balloon observations. We compare the observed and modeled variabilities of temperature, zonal momentum flux and vertical wind speed, which are related to low-, mid- and high-frequency waves, respectively. The probability density function (PDF) distributions have similar shapes but show increasing disagreement with increasing intrinsic frequency. Since at those altitudes they are mainly caused by gravity waves, we also compare the geographic ... Article in Journal/Newspaper Antarc* Antarctic Directory of Open Access Journals: DOAJ Articles Antarctic Merra ENVELOPE(12.615,12.615,65.816,65.816) Atmospheric Chemistry and Physics 20 15 9331 9350 |
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Open Polar |
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ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
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Physics QC1-999 Chemistry QD1-999 A. Podglajen A. Hertzog R. Plougonven B. Legras Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
Due to their increasing spatial resolution, numerical weather prediction (NWP) models and the associated analyses resolve a growing fraction of the gravity wave (GW) spectrum. However, it is unclear how well this “resolved” part of the spectrum truly compares to the actual atmospheric variability. In particular, the Lagrangian variability, relevant, for example, to atmospheric dispersion and to microphysical modeling in the upper troposphere–lower stratosphere (UTLS), has not yet been documented in recent products. To address this shortcoming, this paper presents an assessment of the GW spectrum as a function of the intrinsic (air parcel following) frequency in recent (re)analyses (ERA-Interim, ERA5, the ECMWF operational analysis and MERRA-2). Long-duration, quasi-Lagrangian balloon observations in the equatorial and Antarctic lower stratosphere are used as a reference for the atmospheric spectrum and are compared to synthetic balloon observations along trajectories calculated using the wind and temperature fields of the reanalyses. Overall, the reanalyses represent realistic features of the spectrum, notably the spectral gap between planetary and gravity waves and a peak in horizontal kinetic energy associated with inertial waves near the Coriolis frequency f in the polar region. In the tropics, they represent the slope of the spectrum at low frequency. However, the variability is generally underestimated even in the low-frequency portion of the spectrum. In particular, the near-inertial peak, although present in the reanalyses, has a reduced magnitude compared to balloon observations. We compare the observed and modeled variabilities of temperature, zonal momentum flux and vertical wind speed, which are related to low-, mid- and high-frequency waves, respectively. The probability density function (PDF) distributions have similar shapes but show increasing disagreement with increasing intrinsic frequency. Since at those altitudes they are mainly caused by gravity waves, we also compare the geographic ... |
format |
Article in Journal/Newspaper |
author |
A. Podglajen A. Hertzog R. Plougonven B. Legras |
author_facet |
A. Podglajen A. Hertzog R. Plougonven B. Legras |
author_sort |
A. Podglajen |
title |
Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
title_short |
Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
title_full |
Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
title_fullStr |
Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
title_full_unstemmed |
Lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
title_sort |
lagrangian gravity wave spectra in the lower stratosphere of current (re)analyses |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/acp-20-9331-2020 https://doaj.org/article/e31d971934a5420c91e849f038e81263 |
long_lat |
ENVELOPE(12.615,12.615,65.816,65.816) |
geographic |
Antarctic Merra |
geographic_facet |
Antarctic Merra |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Atmospheric Chemistry and Physics, Vol 20, Pp 9331-9350 (2020) |
op_relation |
https://acp.copernicus.org/articles/20/9331/2020/acp-20-9331-2020.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-20-9331-2020 1680-7316 1680-7324 https://doaj.org/article/e31d971934a5420c91e849f038e81263 |
op_doi |
https://doi.org/10.5194/acp-20-9331-2020 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
20 |
container_issue |
15 |
container_start_page |
9331 |
op_container_end_page |
9350 |
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1766190523922513920 |