Investigation of gravity waves using horizontally resolved radial velocity measurements

Stober, Gunter; Sommer, Svenja; Rapp, Markus; Latteck, R.

doi:10.5194/amt-6-2893-2013

Cited by 48 publications

(50 citation statements)

References 48 publications

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“…The radar system is located at Andøya, Norway (69.03 • N, 16.04 • E) and designed for studying polar atmosphere, i.e. the UTLS (the upper troposphere and lower stratosphere) and MLT (the mesosphere and lower thermosphere) regions covering the ionospheric E region altitudes in polar regions Renkwitz et al, 2012Renkwitz et al, , 2013Stober et al, 2012Stober et al, , 2013Chau et al, 2014;Latteck and Strelnikova, 2015). The basic parameters of the radar system are summarized in Table 1 for convenience.…”

Section: Observationsmentioning

confidence: 99%

Derivation of turbulent energy dissipation rate with the Middle Atmosphere Alomar Radar System (MAARSY) and radiosondes at Andøya, Norway

Rapp

Schrön

et al. 2016

Ann. Geophys.

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Abstract. We present the derivation of turbulent energy dissipation rate ε from a total of 522 days of observations with the Middle Atmosphere Alomar Radar SYstem (MAARSY) mesosphere-stratosphere-troposphere (MST) radar running tropospheric experiments during the period of 2010-2013 as well as with balloon-borne radiosondes based on a campaign in the summer 2013. Spectral widths are converted to ε after the removal of the broadening effects due to the finite beam width of the radar. With the simultaneous in situ measurements of ε with balloon-borne radiosondes at the MAARSY radar site, we compare the ε values derived from both techniques and reach an encouraging agreement between them. Using all the radar data available, we present a preliminary climatology of atmospheric turbulence in the UTLS (upper troposphere and lower stratosphere) region above the MAARSY site showing a variability of more than 5 orders of magnitude inherent in turbulent energy dissipation rates. The derived ε values reveal a log-normal distribution with a negative skewness, and the ε profiles show an increase with height which is also the case for each individual month. Atmospheric turbulence based on our radar measurements reveals a seasonal variation but no clear diurnal variation in the UTLS region. Comparison of ε with the gradient Richardson number Ri shows that only 1.7 % of all the data with turbulence occur under the condition of Ri < 1 and that the values of ε under the condition of Ri < 1 are significantly larger than those under Ri > 1. Further, there is a roughly negative correlation between ε and Ri that is independent of the scale dependence of Ri. Turbulence under active dynamical conditions (velocity of horizontal wind U > 10 m s −1 ) is significantly stronger than under quiet conditions (U < 10 m s −1 ). Last but not least, the derived ε values are compared with the corresponding vertical shears of background wind velocity showing a linear relation with a corresponding correlation coefficient r = 58 % well above the 99.9 % significance level. This implies that wind shears play an important role in the turbulence generation in the troposphere and lower stratosphere (through the Kelvin-Helmholtz instability).

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Section: Observationsmentioning

confidence: 99%

Derivation of turbulent energy dissipation rate with the Middle Atmosphere Alomar Radar System (MAARSY) and radiosondes at Andøya, Norway

Rapp

Schrön

et al. 2016

Ann. Geophys.

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“…44 and 45 in table 2). This is in principle possible and was already 30 observed in the past (see, for example, Manson, 1990, andStober et al, 2013) The mean error following equation (3) sums up to 59% (fig. 2b).…”

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confidence: 93%

Derivation of horizontal and vertical wavelengths using a scanning OH(3-1) airglow spectrometer

Wüst

Offenwanger

Schmidt

et al. 2017

Preprint

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For the first time, we present an approach to derive zonal, meridional and vertical wavelengths as well as periods of gravity waves based on only one OH* spectrometer addressing one vibrational-rotational transition. Knowledge of these parameters 15 is a precondition for the calculation of further information such as the wave group velocity vector.OH(3-1) spectrometer measurements allow the analysis of gravity wave periods, but spatial information cannot necessarily be deduced. We use a scanning spectrometer and the harmonic analysis to derive horizontal wavelengths at the mesopause above Oberpfaffenhofen (48.09°N, 11.28°E), Germany for 22 nights in 2015. Based on the approximation of the dispersion relation for gravity waves of low and medium frequency and additional horizontal wind information, we calculate vertical 20 wavelengths afterwards. The mesopause wind measurements nearest to Oberpfaffenhofen are conducted at Collm (51.30°N, 13.02°E), Germany, ca. 380 km northeast of Oberfpaffenhofen by a meteor radar.In order to check our results, vertical temperature profiles of TIMED-SABER (Thermosphere Ionosphere Mesosphere Energetics Dynamics, Sounding of the Atmosphere using Broadband Emission Radiometry) overpasses are analysed with respect to the dominating vertical wavelength. 25Atmos. Meas. Tech. Discuss., https://doi

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“…Horizontally resolved radial velocities maps using PMSE as passive tracer for neutral dynamics were already introduced by Stober et al (2013). Here, we apply this method to enhance our statistics, investigating several days of our multi-beam observations from 21 June to 30 June 2013.…”

Section: Gravity Wave Statistics Using Horizontally Resolved Radial Vmentioning

confidence: 99%

“…If radial velocities are not available for all beam directions due to the patchy PMSE structure it turns out that the VVP is more suitable and robust (Stober et al, 2013). In addition, the benefit of the VVP technique is to access higher order kinematic terms 25 such as horizontal divergence, stretching and shearing deformation in the wind field.…”

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Observation of Kelvin-Helmholtz Instabilities and gravity waves in the summer mesopause above Andenes in Northern Norway

Stober¹,

Sommer²,

Schult³

et al. 2018

Preprint

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Abstract. We present observations obtained with the Middle Atmosphere Alomar Radar System (MAARSY) to investigate short period wave-like features using polar mesospheric summer echoes (PMSE) as tracer for the neutral dynamics. We conducted a multi-beam experiment including 67 different beam directions during a 9-day campaign in June 2013. We identified two Kelvin Helmholtz Instability (KHI) events from the signal morphology of PMSE. The MAARSY observations are complemented by collocated meteor radar wind data to determine the mesoscale gravity wave activity and the vertical structure of 5 the wind field above the PMSE. The KHIs occurred in a strong shear flow with Richardson numbers Ri < 0.25. In addition, we observed 15 wave-like events in our MAARSY multi-beam observations applying a sophisticated decomposition of the radial velocity measurements using Volume Velocity Processing. We retrieved the horizontal wavelength, intrinsic frequency, propagation direction and phase speed from the horizontally resolved wind variability for 15 events. These events showed horizontal wavelengths between 20-40 km, vertical wavelengths between 5-10 km and rather high intrinsic phase speeds between 45-85 10 m/s with intrinsic periods of 5-10 minutes.

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Investigation of gravity waves using horizontally resolved radial velocity measurements

Cited by 48 publications

References 48 publications

Derivation of turbulent energy dissipation rate with the Middle Atmosphere Alomar Radar System (MAARSY) and radiosondes at Andøya, Norway

Derivation of turbulent energy dissipation rate with the Middle Atmosphere Alomar Radar System (MAARSY) and radiosondes at Andøya, Norway

Derivation of horizontal and vertical wavelengths using a scanning OH(3-1) airglow spectrometer

Observation of Kelvin-Helmholtz Instabilities and gravity waves in the summer mesopause above Andenes in Northern Norway

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