Assessment of the ERA-Interim Winds Using High-Altitude Stratospheric Balloons

Duruisseau, Fabrice; Huret, Nathalie; Andral, Alice; Camy‐Peyret, C.

doi:10.1175/jas-d-16-0137.1

Cited by 18 publications

(13 citation statements)

References 53 publications

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“…This is expected since the reanalysis data contain information from atmospheric wind observations from these altitudes. The number of observations generally reduces with height (Duruisseau et al, 2017). This plot suggests the observational impact of the infrasound measurements to be higher in the levels above around z = 30 km.…”

Section: Observations and Backgroundmentioning

confidence: 85%

Assimilation of atmospheric infrasound data to constrain tropospheric and stratospheric winds

Amezcua

Näsholm

Blixt

et al. 2020

Quart J Royal Meteoro Soc

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This data assimilation study exploits infrasound from explosions to probe an atmospheric wind component from the ground up to stratospheric altitudes. Planned explosions of old ammunition in Finland generate transient infrasound waves that travel through the atmosphere. These waves are partially reflected back towards the ground from stratospheric levels, and are detected at a receiver station located in northern Norway at 178 km almost due north from the explosion site. The difference between the true horizontal direction towards the source and the backazimuth direction (the horizontal direction of arrival) of the incoming infrasound wavefronts, in combination with the pulse propagation time, are exploited to provide an estimate of the average cross‐wind component in the penetrated atmosphere. We perform offline assimilation experiments with an ensemble Kalman filter and these observations, using the ERA5 ensemble reanalysis atmospheric product as background (prior) for the wind at different vertical levels. We demonstrate that information from both sources can be combined to obtain analysis (posterior) estimates of cross‐winds at different vertical levels of the atmospheric slice between the explosion site and the recording station. The assimilation makes greatest impact at the 12–60 km levels, with some changes with respect to the prior of the order of 0.1–1.0 m·s−1, which is a magnitude larger than the typical standard deviation of the ERA5 background. The reduction of background variance in the higher levels often reached 2–5%. This is the first published study demonstrating techniques to implement assimilation of infrasound data into atmospheric models. It paves the way for further exploration in the use of infrasound observations – especially natural and continuous sources – to probe the middle atmospheric dynamics and to assimilate these data into atmospheric model products.

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Section: Observations and Backgroundmentioning

confidence: 85%

Assimilation of atmospheric infrasound data to constrain tropospheric and stratospheric winds

Amezcua

Näsholm

Blixt

et al. 2020

Quart J Royal Meteoro Soc

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“…Generally, ERA‐Interim describes the zonal mean stratospheric circulation and transport characteristics very well in comparison to observations, but with some deficiencies particularly in the middle and upper stratosphere (Dee et al, ). Such deficiencies are due to the lack in globally covered wind measurements between the maximum altitude of standard radiosondes (~30 km) and the minimum altitude of satellite‐based wind measurements in the upper mesosphere (~80 km; e.g., Baron et al, ; Duruisseau et al, ), but also to deficiencies in the assimilation model (e.g., Coy et al, ). In particular, uncertainties were discussed concerning the forcing of the zonal mean tropical upwelling by gravity wave fluxes (Seviour et al, ) and the damping of vertically propagating planetary waves at the upper boundary of the assimilation model at 0.1 hPa (Gabriel et al, , b).…”

Section: Methodsmentioning

confidence: 99%

Long‐Term Changes in the Northern Midwinter Middle Atmosphere in Relation to the Quasi‐Biennial Oscillation

Gabriel

2019

JGR Atmospheres

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Long‐term changes in the middle atmosphere due to anthropogenic greenhouse gas emissions are examined in relation to the effect of the equatorial Quasi‐Biennial Oscillation (QBO) on the northern midwinter circulation. The examinations are based on the Coupled Model Intercomparison Project Phase 5 simulations for 1979–2100 with the Earth‐System‐Model MPI‐ESM‐MR that generates the QBO internally. In particular, the three‐dimensional residual circulation is used as proxy for the Brewer‐Dobson circulation, revealing an increasing downwelling in the center of the polar low over Northern Europe/Siberia (~5% per decade). The changes in northern midwinter temperature, zonal wind, and residual circulation are much stronger during westerly (QBO‐W) than easterly (QBO‐E) phase of QBO (e.g., for a moderate increase in greenhouse gases, we find maximum decreases in the zonal mean westerly jet at 60°N and 3 hPa of about −14.8 ± 5.4 m/s for QBO‐W but only −4.7 ± 5.2 m/s for QBO‐E). This is due to a change of the extratropical QBO‐W signature toward QBO‐E signature while the equatorial QBO remains nearly unchanged (i.e., a change toward disappearance of the so‐called Holton‐Tan relationship). Similar to the current change from QBO‐W to QBO‐E signature, the changes during QBO‐W include an increase in amplitude and eastward shift in phase of stratospheric stationary Wave 1 at the cost of Wave 2, with decreasing westerlies over North America and increasing downwelling over Siberia. The eastward shift in phase of stationary Wave 1 is related to the associated increase in meridional transport of planetary vorticity.

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“…A better understanding of these phenomena, in addition to global middle-atmospheric wind measurements, would significantly improve our knowledge of the climate system. Not discussed in this paper is the capability of SIW for measuring ice water content in the tropical upper troposphere (Eriksson et al, 2014). Observing the same air mass from two perpendicular directions could provide interesting information considering the high spatial inhomogeneities of cloudy conditions.…”

Section: Discussionmentioning

confidence: 99%

revised manuscript

Baron¹

2018

Preprint

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Stratospheric Inferred Winds (SIW) is a Swedish mini sub-millimeter limb sounder selected for the 2nd In-noSat platform, with launch planned for around 2022. It is intended to fill the altitude gap between 30 and 70 km in atmospheric wind measurements and also aims at pursuing the limb observations of temperature and key atmospheric constituents between 10 and 90 km when current satellite missions will probably come to an end. Line-of-sight winds are retrieved from the Doppler shift of molecular emission lines introduced by the wind field. Observations will be performed with two antennas pointing toward the limb in perpendicular directions in order to reconstruct the 2-D horizontal wind vector. Each antenna has a vertical field of view (FOV) of 5 km. The chosen spectral band, near 655 GHz, contains a dense group of strong O 3 lines suitable for exploiting the small amount of wind information in stratospheric spectra. Using both sidebands of the heterodyne receiver, a large number of chemical species will be measured, including O 3 isotopologues, H 2 O, HDO, HCl, ClO, N 2 O, HNO 3 , NO, NO 2 , HCN, CH 3 CN and HO 2. This paper presents a simulation study that assesses measurement performance. The line-of-sight winds are retrieved between 30 and 90 km with the best sensitivity between 35 and 70 km, where the precision (1σ) is 5-10 m s −1 for a single scan. Similar performance can be obtained during day and night conditions except in the lower mesosphere, where the photo-dissociation of O 3 in daytime reduces the sensitivity by 50 % near 70 km. Profiles of O 3 , H 2 O and temperature are retrieved with high precision up to 50 km (< 1 %, < 2 %, 1 K, respectively). Systematic errors due to uncertainties in spectroscopic parameters, in the radiometer sideband ratio and in the radiance calibration process are investigated. A large wind retrieval bias of 10-30 m s −1 between 30 and 40 km could be induced by the air-broadening parameter uncertainties of O 3 lines. This highlights the need for good knowledge of these parameters and for studying methods to mitigate the retrieval bias.

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Assessment of the ERA-Interim Winds Using High-Altitude Stratospheric Balloons

Cited by 18 publications

References 53 publications

Assimilation of atmospheric infrasound data to constrain tropospheric and stratospheric winds

Assimilation of atmospheric infrasound data to constrain tropospheric and stratospheric winds

Long‐Term Changes in the Northern Midwinter Middle Atmosphere in Relation to the Quasi‐Biennial Oscillation

revised manuscript

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