GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

Ern, Manfred; Trinh, Quang Thai; Preusse, Peter; Gille, J. C.; Mlynczak, Martin G.; Russell, James M.; Riese, Martin

doi:10.5194/essd-10-857-2018

Cited by 135 publications

(233 citation statements)

References 122 publications

(231 reference statements)

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“…Additionally, these calculations are an average estimate over the entire flight path, and localized MFs due to stronger phases over the mountains and directly in the lee of the mountains likely have larger associated MFs. Regardless of this, the spectral MF calculations show MF values that are larger than the average background MF values previously measured by radars and satellites, which have ranged from~1 to 20 m 2 /s 2 (Ern et al, 2018;Fritts et al, 2010Fritts et al, , 2012Fritts & Vincent, 1987;Murphy & Vincent, 1993;Nakamura et al, 1993;Reid et al, 1988;Tsuda et al, 1990;Vincent & Reid, 1983;Wang & Fritts, 1990). This finding is qualitatively in good agreement with Hertzog et al (2012), who showed that MW events are particularly intermittent and strong events can carry very large MFs.…”

Section: Mf Spectra Calculationssupporting

confidence: 81%

Momentum Flux Spectra of a Mountain Wave Event Over New Zealand

et al. 2018

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During the Deep Propagating Gravity Wave Experiment (DEEPWAVE) 13 July 2014 research flight over the South Island of New Zealand, a multiscale spectrum of mountain waves (MWs) was observed. High‐resolution measurements of sodium densities were available from ~70 to 100 km for the duration of this flight. A comprehensive technique is presented for obtaining temperature perturbations, T′, from sodium mixing ratios over a range of altitudes, and these T′ were used to calculate the momentum flux (MF) spectra with respect to horizontal wavelengths, λH, for each flight segment. Spectral analysis revealed MWs with spectral power centered at λH of ~80, 120, and 220 km. The temperature amplitudes of these MWs varied between the four cross‐mountain flight legs occurring between 6:10UT and 9:10UT. The average spectral T′ amplitudes near 80 km in altitude ranged from 7–13 K for the 220 km λH MW and 4–8 K for the smaller λH MWs. These amplitudes decayed significantly up to 90 km, where a critical level for MWs was present. The average MF per unit mass near 80 km in altitude ranged from ~13 to 60 m2/s2 across the varying spectra over the duration of the research flight and decayed to ~0 by 88 km in altitude. These MFs are large compared to zonal means and highlight the importance of MWs in the momentum budget of the mesosphere and lower thermosphere at times when they reach these altitudes.

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Section: Mf Spectra Calculationssupporting

confidence: 81%

Momentum Flux Spectra of a Mountain Wave Event Over New Zealand

et al. 2018

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“…Li et al (2016) further found indication that this variation in GW activity may be linked to variations in convective activity. Long-term observations of GW variances and GWMF are available from a number of ground-based observations (e.g., Tsuda et al, 1990;Espy et al, 2004;Hoffmann et al, 2010), but from these it is difficult to compare the intensity of interannual and intra-annual variability at different latitudes. However, a full global picture of the temporal spectrum of GW variations is still missing.…”

Section: Introductionmentioning

confidence: 99%

Global analysis for periodic variations in gravity wave squared amplitudes and momentum fluxes in the middle atmosphere

Chen

Strube²,

Ern³

et al. 2019

Ann. Geophys.

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Abstract. Atmospheric gravity waves (GWs) are an important coupling mechanism in the middle atmosphere. For instance, they provide a large part of the driving of long-period atmospheric oscillations such as the Quasi-Biennial Oscillation (QBO) and the semiannual oscillation (SAO) and are in turn modulated. They also induce the wind reversal in the mesosphere–lower thermosphere region (MLT) and the residual mean circulation at these altitudes. In this study, the variations in monthly zonal mean gravity wave square temperature amplitudes (GWSTAs) and, for the first time, absolute gravity wave momentum flux (GWMF) on different timescales such as the annual, semiannual, terannual and quasi-biennial variations are investigated by spectrally analyzing SABER observations from 2002 to 2015. Latitude–altitude cross sections of spectral amplitudes and phases of GWSTA and absolute GWMF in the stratosphere and mesosphere are presented and physically interpreted. It is shown that the time series of GWSTA and GWMF at a certain altitude and latitude results from the complex interplay of GW sources, propagation through and filtering in lower altitudes, oblique propagation superposing GWs from different source locations, and, finally, the modulation of the GW spectrum by the winds at a considered altitude and latitude. The strongest component is the annual variation, dominated in the summer hemisphere by subtropical convective sources and in the winter hemisphere by polar vortex dynamics. At heights of the wind reversal, a 180∘ phase shift also occurs, which is at different altitudes for GWSTA and GWMF. In the intermediate latitudes a semiannual variation (SAV) is found. Dedicated GW modeling is used to investigate the nature of this SAV, which is a different phenomenon from the tropical SAO also seen in the data. In the tropics a stratospheric and a mesospheric QBO are found, which are, as expected, in antiphase. Indication for a QBO influence is also found at higher latitudes. In previous studies a terannual variation (TAV) was identified. In the current study we explain its origin. In particular the observed patterns for the shorter periods, SAV and TAV, can only be explained by poleward propagation of GWs from the lower-stratosphere subtropics into the midlatitude and high-latitude mesosphere. In this way, critical wind filtering in the lowermost stratosphere is avoided and this oblique propagation is hence likely an important factor for MLT dynamics.

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“…Moreover, they provide a favourable medium for the vertical propagation of internal gravity waves excited in the troposphere (e.g., Preusse et al 2006, Ern et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Mesoscale fine structure of a tropopause fold over mountains

Woiwode¹,

Dörnbrack²,

Bramberger³

et al. 2018

Preprint

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We report airborne remote-sensing observations of a tropopause fold during two crossings of the polar 10 front jet over Northern Italy on 12 January 2016. The GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) observations allowed for a simultaneous mapping of temperature, water vapour and ozone.They revealed deep, dry and ozone rich intrusions into the troposphere. The mesoscale fine structures of dry filaments at the cyclonic shear side of the jet and tongues of moist air entraining tropospheric air into the stratosphere along the anticyclonic shear side were clearly resolved by GLORIA observations. Vertically 15 propagating mountain waves with recorded temperature residuals exceeding ± 3 K were detected above the Apennines. Their presence enhanced gradients of all variables locally in the vicinity of the tropopause. The combination of H2O-O3-correlations with potential temperature reveals an active mixing region and shows clear evidence of troposphere-to-stratosphere and stratosphere-to-troposphere exchange. High-resolution short-term deterministic forecasts of ECMWF's integrated forecast system (IFS) applying GLORIA's observational filter 20 reproduce location, shape, and depth of the tropopause fold very well. The fine structure of the mixing region, however, cannot be reproduced even with the used 9 km horizontal resolution of the IFS. This case study demonstrates convincingly the capabilities of linear limb-imaging observations to resolve mesoscale fine structures in the upper troposphere and lower stratosphere, validates the high quality of the IFS data, and suggests that mountain wave perturbations have the potential to modulate exchange processes in the vicinity of tropopause folds. 25Atmos. Chem. Phys. Discuss., https://doi.

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GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings

Cited by 135 publications

References 122 publications

Momentum Flux Spectra of a Mountain Wave Event Over New Zealand

Momentum Flux Spectra of a Mountain Wave Event Over New Zealand

Global analysis for periodic variations in gravity wave squared amplitudes and momentum fluxes in the middle atmosphere

Mesoscale fine structure of a tropopause fold over mountains

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