Temporal variability of tidal and gravity waves during a record long 10-day continuous lidar sounding

Baumgarten, Kathrin; Gerding, M.; Baumgarten, Gerd; Lübken, Franz‐Josef

doi:10.5194/acp-18-371-2018

Cited by 48 publications

(52 citation statements)

References 43 publications

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“…Typically, observations are limited either to a detection of temperatures or winds. Tidal information based on both quantities was simultaneously derived in the past from model outputs, e.g., from the Kühlungsborn Mechanistic General Circulation Model (KMCM) by Becker (2017). This study addresses the heat budget of the mesosphere and lower thermosphere regarding upward-propagating thermal tides.…”

Section: Discussionmentioning

confidence: 99%

On the evaluation of the phase relation between temperature and wind tides based on ground-based measurements and reanalysis data in the middle atmosphere

Baumgarten

Stober

2019

Ann. Geophys.

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Abstract. The variability in the middle atmosphere is driven by a variety of waves covering different spatial and temporal scales. We diagnose the variability in the thermal tides due to changes in the background wind by an adaptive spectral filter, which takes the intermittency of tides into account. We apply this diagnostic to temperature observations from daylight-capable lidar at midlatitudes (54∘ N, 12∘ E) as well as to reanalysis data of horizontal winds from Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). These reanalysis data provide additional wind information in the altitude range between 30 and 70 km at the location of the lidar as well as on a global scale. Using the global data gives information on the tidal modes seen at one location. A comparison of the temperature and wind information affirms whether there is a fixed phase relation of the tidal waves in the temperature and the wind data. We found that in general the local tidal signatures are dominated by migrating tidal modes, and the signature is weaker in temperatures than in winds. While the meridional wind tide leads the zonal wind tide by 90∘, the phase relation between the temperature and the wind tide is more complex. At certain altitudes the temperature tide follows the zonal wind tide. This knowledge helps in improving the interpretation of the seasonal variation in tides from different observables, especially when only data from single locations are used. The findings provide additional information about the phase stability of tidal waves, and the results clearly show the importance of a measurement acquisition on a routine basis with high temporal and spatial resolution.

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Section: Discussionmentioning

confidence: 99%

On the evaluation of the phase relation between temperature and wind tides based on ground-based measurements and reanalysis data in the middle atmosphere

Baumgarten

Stober

2019

Ann. Geophys.

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“…It should also be remembered that, in contrast to the mesopause region, tides are usually weak in the stratosphere and lower mesosphere (e.g. Baumgarten et al, 2018;Kopp et al, 2015;Sakazaki et al, 2018).…”

Section: Geostrophic Wind From the Mls Geopotential Height Fieldmentioning

confidence: 99%

Intercomparison of middle-atmospheric wind in observations and models

et al. 2018

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Wind profile information throughout the entire upper stratosphere and lower mesosphere (USLM) is important for the understanding of atmospheric dynamics but became available only recently, thanks to developments in remote sensing techniques and modelling approaches. However, as wind measurements from these altitudes are rare, such products have generally not yet been validated with (other) observations. This paper presents the first long-term intercomparison of wind observations in the USLM by colocated microwave radiometer and lidar instruments at Andenes, Norway (69.3 • N, 16.0 • E). Good correspondence has been found at all altitudes for both horizontal wind components for nighttime as well as daylight conditions. Biases are mostly within the random errors and do not exceed 5-10 m s −1 , which is less than 10 % of the typically encountered wind speeds. Moreover, comparisons of the observations with the major reanalyses and models covering this altitude range are shown, in particular with the recently released ERA5, ECMWF's first reanalysis to cover the whole USLM region. The agreement between models and observations is very good in general, but temporally limited occurrences of pronounced discrepancies (up to 40 m s −1 ) exist. In the article's Appendix the possibility of obtaining nighttime wind information about the mesopause region by means of microwave radiometry is investigated.

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“…We note that this current analysis is limited to a single day (24 h) and not a composite of 180 h of measurements during a period of 12 days as in Lübken et al (2011). Due to the high variability in tidal phases and amplitudes (e.g., Murphy et al,15 2006; Baumgarten et al, 2018) the results of a single day (our dataset) are to be expected to deviate to some extend in phase (several hours) and amplitude from an average (Lübken et al, 2011).…”

Section: Discussionmentioning

confidence: 98%