Wind-profiler observations of gravity waves produced by convection at mid-latitudes

Choi, Yun Gyeong; Lee, S. C.; McDonald, A. J.; Hooper, David A

doi:10.5194/acp-6-2825-2006

Cited by 10 publications

(6 citation statements)

References 34 publications

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“…[18] The estimated horizontal and vertical intrinsic phase velocities are 5.7 m s À1 and 1.4 m s À1 , and group velocities are 6 m s À1 and 1.5 m s À1 , respectively. The observed characteristics of the wave is consistent with the earlier observations associated with cumulus convections over midlatitudes [Dhaka et al, 2003;Sato, 1993;Choi et al, 2006]. Details of wave parameters estimated are given in Table 2.…”

Section: Characteristics Of Short-period Gravity Wave At Utls Regionsupporting

confidence: 87%

MST radar observations of short‐period gravity wave during overhead tropical cyclone

Das¹,

Uma²,

Das³

2012

Radio Science

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Short‐period gravity waves associated with the passage of tropical cyclone using mesosphere‐stratosphere‐troposphere (MST) radar located at Gadanki (13.5°N, 79.2°E) has been discussed. The observed stratospheric gravity wave is found to have a periodicity of ∼42 min, vertical and horizontal wavelength of ∼3.5 km and 14 km, respectively. Maximum amplitude of gravity wave is observed in the upper troposphere and lower stratosphere (UTLS) region due to which periodic updrafts and downdrafts are observed. This weakens the stability of tropopause, which is observed in radar signal‐to‐noise ratio (SNR). The enhancement of vertical momentum flux of order ∼−0.6 m2/s2 observed in the lower stratosphere is attributed to the cyclone generated gravity waves. The obstacle effect is found to be the generative mechanism for the observed gravity waves associated with the tropical cyclone.

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Section: Characteristics Of Short-period Gravity Wave At Utls Regionsupporting

confidence: 87%

MST radar observations of short‐period gravity wave during overhead tropical cyclone

Das¹,

Uma²,

Das³

2012

Radio Science

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“…The MST wind profiler at Aberystwyth, Wales (52.4°N, 4.1°W -see Figure 1(c)) is supported by NERC, and has been used previously for analysis of CGWs by Choi et al (2006). The instrument operates at a frequency of 46.5 MHz with a peak transmission energy of 160 kW.…”

Section: Mst Wind Profilermentioning

confidence: 99%

“…Several recent studies of gravity waves have used wind profilers to observe the evolution of the vertical profile of the wind field (e.g. Pavelin et al, 2001;Bohme et al, 2004;Hooper et al, 2005;Choi et al, 2006). One shortfall of this method of observation is that it cannot be used directly to examine the horizontal structure of a wave field.…”

Section: Introductionmentioning

confidence: 99%

Analysis of convectively‐generated gravity waves in mesoscale model simulations and wind‐profiler observations

Chagnon

Gray

2008

Quart J Royal Meteoro Soc

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ABSTRACT:The characteristics of convectively-generated gravity waves during an episode of deep convection near the coast of Wales are examined, in high-resolution mesoscale simulations with the Met Office Unified Model and in observations from a mesosphere-stratosphere-troposphere wind-profiling Doppler radar. In this episode, deep convection reached the tropopause and generated vertically-propagating high-frequency waves in the lower stratosphere that produced vertical-velocity perturbations of order of 1 ms −1 . Wavelet analysis is applied in order to determine the characteristic periods and wavelengths of the waves. Both in the simulations and in the observations, the wavelet spectra contain several distinct preferred scales, indicated by multiple spectral peaks. The peaks are most pronounced in the horizontal spectra at several wavelengths less than 50 km. Although these peaks are most clear, and of largest amplitude, in the highest-resolution simulations (with 1 km horizontal grid length), they are also evident in coarser simulations (with 4 km horizontal grid length). Peaks also exist in the vertical and temporal spectra (at approximately 2.5-4.5 km and 10-30 min respectively), with good agreement between simulation and observation. Two-dimensional (wave-number-frequency) spectra demonstrate that each of the selected horizontal scales contains peaks at each of the preferred temporal scales revealed by the onedimensional spectra alone.

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“…Radiosonde ascent rate is approximately 5 m s − 1 and time resolution 2 s giving height resolution approximately 10 m. The MST radar dataset was searched visually for turbulent layers shown by increased vertical-beam spectral width corrected for beam broadening (Hocking, 1985;Wilson, 2004), in conditions of small vertical shear of horizontal wind and no breaking mountain waves. These atypical turbulent layers are unexplained by the mechanisms studied by Pepler et al (1998), Worthington and Thomas (1996), Worthington (1998), Pavelin et al (2001), Reid and Vaughan (2004), Hooper et al (2005), and Choi et al (2006) using the same radar.…”

Section: Case Studies Aberystwyth Mst Radarmentioning

confidence: 89%

“…More recently, MST radar work again focused on disturbed conditions, with turbulence from jet-stream wind shear (Pepler et al, 1998), inertia-gravity wave wind shear (Pavelin et al, 2001), breaking mountain waves (Worthington and Thomas, 1996;Worthington, 1998) or deep convection (Reid and Vaughan, 2004;Hooper et al, 2005;Choi et al, 2006). This study examines another common type of turbulent layer which does not fit into any of these categories: altocumulus layers in the absence of unusually strong wind shear or breaking gravity waves, in otherwise undisturbed weather.…”

Section: Introductionmentioning

confidence: 99%

MST radar observations of turbulent altocumulus layers

Worthington¹

2015

Atmospheric Science Letters

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Radar studies of turbulent layers have focused on Kelvin-Helmholtz instabilities caused by vertical shear of horizontal wind, also breaking gravity waves. This study examines another type of turbulent layer, common but rarely studied. Aberystwyth Meso-Strato-Troposphere (MST) radar shows layers of turbulence where there is no unusual wind shear or breaking gravity waves. In three case studies, these layers have a common characteristic of saturated air, reducing the stability to cause possible convective or shear instability. The associated cloud may be already well-known altocumulus. Another case study using the MU radar shows how three-dimensional convective structure can be revealed using a 64-beam method.

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Wind-profiler observations of gravity waves produced by convection at mid-latitudes

Cited by 10 publications

References 34 publications

MST radar observations of short‐period gravity wave during overhead tropical cyclone

MST radar observations of short‐period gravity wave during overhead tropical cyclone

Analysis of convectively‐generated gravity waves in mesoscale model simulations and wind‐profiler observations

MST radar observations of turbulent altocumulus layers

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