Tomographic retrieval approach for mesoscale gravity wave observations by the PREMIER Infrared Limb-Sounder

Ungermann, Jörn; Hoffmann, Lars; Preusse, Peter; Kaufmann, Martín; Riese, Martin

doi:10.5194/amt-3-339-2010

Cited by 44 publications

(52 citation statements)

References 50 publications

(56 reference statements)

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“…This sensitivity decreases close to the detection limits at short horizontal and short vertical wavelengths. Satellite instruments observing in limb-viewing geometry can only detect gravity waves with horizontal wavelengths > 100-200 km (see also Preusse et al, 2002Preusse et al, , 2009Ungermann et al, 2010), and therefore observe only part of the momentum flux of the whole spectrum of gravity waves (e.g., Ern et al, 2005;Choi et al, 2012). Further, the vertical resolution of an instrument limits the range of vertical wavelengths that can be detected.…”

Section: Estimation Of Absolute Momentum Fluxesmentioning

confidence: 99%

“…Because of their importance, the tropics have been the focus of previous measurement campaigns and will be the topic of future ones (e.g., Deepa et al, 2006;Cairo et al, 2010;Jewtoukoff et al, 2013;von Hobe et al, 2013). In addition, modeling efforts are currently underway to improve the representation of the tropics and, in particular, the QBO in weather and climate models (e.g., Yang et al, 2009;Kim et al, 2013;Kim and Chun, 2015;Lott et al, 2012Lott et al, , 2014Krismer and Giorgetta, 2014;Maury and Lott, 2014;Richter et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Driving of the SAO by gravity waves as observed from satellite

Ern¹,

Preusse²,

Riese³

2015

Ann. Geophys.

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Abstract. It is known that atmospheric dynamics in the tropical stratosphere have an influence on higher altitudes and latitudes as well as on surface weather and climate. In the tropics, the dynamics are governed by an interplay of the quasi-biennial oscillation (QBO) and semiannual oscillation (SAO) of the zonal wind. The QBO is dominant in the lower and middle stratosphere, and the SAO in the upper stratosphere/lower mesosphere. For both QBO and SAO the driving by atmospheric waves plays an important role. In particular, the role of gravity waves is still not well understood.In our study we use observations of the High Resolution Dynamics Limb Sounder (HIRDLS) satellite instrument to derive gravity wave momentum fluxes and gravity wave drag in order to investigate the interaction of gravity waves with the SAO. These observations are compared with the ERA-Interim reanalysis. Usually, QBO westward winds are much stronger than QBO eastward winds. Therefore, mainly gravity waves with westward-directed phase speeds are filtered out through critical-level filtering already below the stratopause region. Accordingly, HIRDLS observations show that gravity waves contribute to the SAO momentum budget mainly during eastward wind shear, and not much during westward wind shear. These findings confirm theoretical expectations and are qualitatively in good agreement with ERA-Interim and other modeling studies. In ERAInterim most of the westward SAO driving is due to planetary waves, likely of extratropical origin. Still, we find in both observations and ERA-Interim that sometimes westwardpropagating gravity waves may contribute to the westward driving of the SAO. Four characteristic cases of atmospheric background conditions are identified. The forcings of the SAO in these cases are discussed in detail, supported by gravity wave spectra observed by HIRDLS. In particular, we find that the gravity wave forcing of the SAO cannot be explained by critical-level filtering alone; gravity wave saturation without critical levels being reached is also important.

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Section: Estimation Of Absolute Momentum Fluxesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Driving of the SAO by gravity waves as observed from satellite

Ern¹,

Preusse²,

Riese³

2015

Ann. Geophys.

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“…They could, however, be remedied, if an instrument were designed for the purpose of measuring GWs (Riese et al, 2005;Preusse et al, 2009b). Viewing backward and sampling sufficiently frequently, 2-D tomographic retrievals can be employed, which allow to reconstruct the true amplitude in that part of the spectrum generally visible to limb sounders (Ungermann et al, 2010). This largely simplifies the visibility filter and strongly reduces its effect.…”

Section: A1 Potential Future Limb Imagermentioning

confidence: 99%

A comprehensive observational filter for satellite infrared limb sounding of gravity waves

Trinh¹,

Kalisch²,

Preusse³

et al. 2015

Atmos. Meas. Tech.

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Abstract. This paper describes a comprehensive observational filter for satellite infrared limb sounding of gravity waves. The filter considers instrument visibility and observation geometry with a high level of accuracy. It contains four main processes: visibility filter, projection of the wavelength on the tangent-point track, aliasing effect, and calculation of the observed vertical wavelength. The observation geometries of the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) and HIRDLS (High Resolution Dynamics Limb Sounder) are mimicked. Gravity waves (GWs) simulated by coupling a convective GW source (CGWS) scheme and the gravity wave regional or global ray tracer (GROGRAT) are used as an example for applying the observational filter. Simulated spectra in terms of horizontal and vertical wave numbers (wavelengths) of gravity wave momentum flux (GWMF) are analyzed under the influence of the filter. We find that the most important processes, which have significant influence on the spectrum are the visibility filter (for both SABER and HIRDLS observation geometries) and aliasing for SABER and projection on tangent-point track for HIRDLS. The vertical wavelength distribution is mainly affected by the retrieval as part of the "visibility filter" process. In addition, the short-horizontalscale spectrum may be projected for some cases into a longer horizontal wavelength interval which originally was not populated. The filter largely reduces GWMF values of very short horizontal wavelength waves. The implications for interpreting observed data are discussed.

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“…by pointing at one particular region while the instrument is flying by. Such tomographic retrievals have been demonstrated and implemented in a variety of measurements for different purposes, including by Carlotti et al (2001) for Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), Livesey and Read (2000) for MLS, Ungermann et al (2010a) for Process Exploration through Measurements of Infrared and millimetre-wave Emitted Radiation (PREMIER), and Ungermann et al (2011) and Kaufmann et al (2015) for the airborne GLORIA instrument. In this work, we propose to combine satellite-borne limb and sub-limb measurements of a nightglow layer in such a way that we obtain multi-angle observations of a particular air volume as well.…”

Section: Observation Strategymentioning

confidence: 99%

“…However, for a tomographic retrieval this is computationally very expensive. Alternatively, we can derive the GW sensitivity function more efficiently by using the averaging kernel matrix method (Ungermann et al, 2010a). The basic idea of this method is to assume that the forward model can be approximated linearly for a small perturbation as induced by a GW.…”

Section: Sensitivity Studymentioning

confidence: 99%

Tomographic reconstruction of atmospheric gravity wave parameters from airglow observations

et al. 2017

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Abstract. Gravity waves (GWs) play an important role in the dynamics of the mesosphere and lower thermosphere (MLT). Therefore, global observations of GWs in the MLT region are of particular interest. The small scales of GWs, however, pose a major problem for the observation of GWs from space. We propose a new observation strategy for GWs in the mesopause region by combining limb and sub-limb satellite-borne remote sensing measurements for improving the spatial resolution of temperatures that are retrieved from atmospheric soundings. In our study, we simulate satellite observations of the rotational structure of the O 2 A-band nightglow. A key element of the new method is the ability of the instrument or the satellite to operate in so-called "target mode", i.e. to point at a particular point in the atmosphere and collect radiances at different viewing angles. These multi-angle measurements of a selected region allow for tomographic 2-D reconstruction of the atmospheric state, in particular of GW structures. The feasibility of this tomographic retrieval approach is assessed using simulated measurements. It shows that one major advantage of this observation strategy is that GWs can be observed on a much smaller scale than conventional observations. We derive a GW sensitivity function, and it is shown that "target mode" observations are able to capture GWs with horizontal wavelengths as short as ∼ 50 km for a large range of vertical wavelengths. This is far better than the horizontal wavelength limit of 100-200 km obtained from conventional limb sounding.

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Tomographic retrieval approach for mesoscale gravity wave observations by the PREMIER Infrared Limb-Sounder

Cited by 44 publications

References 50 publications

Driving of the SAO by gravity waves as observed from satellite

Driving of the SAO by gravity waves as observed from satellite

A comprehensive observational filter for satellite infrared limb sounding of gravity waves

Tomographic reconstruction of atmospheric gravity wave parameters from airglow observations

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