Generation of Gravity Waves by Jet Streams in the Atmosphere

Mastrantonio, G.; Einaudi, Franco; Fuà, D.; Lalas, D. P.

doi:10.1175/1520-0469(1976)033<1730:gogwbj>2.0.co;2

Cited by 68 publications

(37 citation statements)

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“…In our case, whenever phase speed was low for short horizontal wavelength waves, the wave did not reach the troposphere and was stopped at mesospheric altitude itself. While there is strong evidence for convectively generated gravity waves, evidence of tropospheric wind-shear-generated GWs is rather sparse (Mastrantonio 1976;Fritts and Alexander 2003). The present study clearly demonstrated that high-frequency, high-phase-speed GWs observed in the mesosphere can be generated by tropospheric wind shear.…”

Section: Discussionmentioning

confidence: 45%

Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique

et al. 2015

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Abstract. Sources and propagation characteristics of highfrequency gravity waves observed in the mesosphere using airglow emissions from Gadanki (13.5 • N, 79.2 • E) and Hyderabad (17.5 • N, 78.5 • E) are investigated using reverse ray tracing. Wave amplitudes are also traced back, including both radiative and diffusive damping. The ray tracing is performed using background temperature and wind data obtained from the MSISE-90 and HWM-07 models, respectively. For the Gadanki region, the suitability of these models is tested. Further, a climatological model of the background atmosphere for the Gadanki region has been developed using nearly 30 years of observations available from a variety of groundbased (MST radar, radiosondes, MF radar) and rocket-and satellite-borne measurements. ERA-Interim products are utilized for constructing background parameters corresponding to the meteorological conditions of the observations. With the reverse ray-tracing method, the source locations for nine wave events could be identified to be in the upper troposphere, whereas for five other events the waves terminated in the mesosphere itself. Uncertainty in locating the terminal points of wave events in the horizontal direction is estimated to be within 50-100 km and 150-300 km for Gadanki and Hyderabad wave events, respectively. This uncertainty arises mainly due to non-consideration of the day-to-day variability in the tidal amplitudes. Prevailing conditions at the terminal points for each of the 14 events are provided. As no convection in and around the terminal points is noticed, convection is unlikely to be the source. Interestingly, large (∼ 9 m s −1 km −1 ) vertical shears in the horizontal wind are noticed near the ray terminal points (at 10-12 km altitude) and are thus identified to be the source for generating the observed highphase-speed, high-frequency gravity waves.

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Section: Discussionmentioning

confidence: 45%

Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique

et al. 2015

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“…These processes include vertical shear instability (Mastrantonio et al, 1976;Bosart and Sanders, 1986), ageostrophic adjustment associated with unbalanced flow (Zack and Kaplan, 1987;Koch and Dorian, 1988), intense convection (Curry andMurty, 1974, Raymond, 1983), and terrain effects (Kaplan and Karyampudi, 1992;Zulicke and Peters, 2006). Here, the squall line developed in the provinces of Anhui and Jiangsu, where the topography is flat; thus, the terrain effect can be excluded.…”

Section: Generation Of Gravity Wavesmentioning

confidence: 99%

Analysis of the structure and propagation of a simulated squall line on 14 June 2009

2015

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A squall line on 14 June 2009 in the provinces of Jiangsu and Anhui was well simulated using the Advanced Regional Prediction System (ARPS) model. Based on high resolution spatial and temporal data, a detailed analysis of the structural features and propagation mechanisms of the squall line was conducted. The dynamic and thermodynamic structural characteristics and their causes were analyzed in detail. Unbalanced flows were found to play a key role in initiating gravity waves during the squall line's development. The spread and development of the gravity waves were sustained by convection in the wave-CISK process. The squall line's propagation and development mainly relied on the combined effect of gravity waves at the midlevel and cold outflow along the gust front. New cells were continuously forced by the cold pool outflow and were enhanced and lifted by the intense upward motion. At a particular phase, the new cells merged with the updraft of the gravity waves, leading to an intense updraft that strengthened the squall line.

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“…The neutral wind effect on AGWs is illustrated in Fig. 1e using a simulated wind profile U x (z) that includes a model tropospheric jet stream (Mastrantonio et al, 1976). When the AGW phase velocity is comparable to the wind velocity, the rays deviate significantly from the windless case (for α 0 >84 • in Fig.…”

Section: Ray Tracing Of Gravity Wavesmentioning

confidence: 99%

The influence of solar wind on extratropical cyclones – Part 2: A link mediated by auroral atmospheric gravity waves?

2009

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Abstract. Cases of mesoscale cloud bands in extratropical cyclones are observed a few hours after atmospheric gravity waves (AGWs) are launched from the auroral ionosphere. It is suggested that the solar-wind-generated auroral AGWs contribute to processes that release instabilities and initiate slantwise convection thus leading to cloud bands and growth of extratropical cyclones. Also, if the AGWs are ducted to low latitudes, they could influence the development of tropical cyclones. The gravity-wave-induced vertical lift may modulate the slantwise convection by releasing the moist symmetric instability at near-threshold conditions in the warm frontal zone of extratropical cyclones. Latent heat release associated with the mesoscale slantwise convection has been linked to explosive cyclogenesis and severe weather. The circumstantial and statistical evidence of the solar wind influence on extratropical cyclones is further supported by a statistical analysis of high-level clouds (<440 mb) extracted from the International Satellite Cloud Climatology Project (ISCCP) D1 dataset. A statistically significant response of the high-level cloud area index (HCAI) to fast solar wind from coronal holes is found in mid-tohigh latitudes during autumn-winter and in low latitudes during spring-summer. In the extratropics, this response of the HCAI to solar wind forcing is consistent with the effect on tropospheric vorticity found by Wilcox et al. (1974) and verified by Prikryl et al. (2009). In the tropics, the observed HCAI response, namely a decrease in HCAI at the arrival of solar wind stream followed by an increase a few days later, is similar to that in the northern and southern mid-to-high latitudes. The amplitude of the response nearly doubles for stream interfaces associated with the interplanetary magnetic field B Z component shifting southward. When the IMF B Z after the stream interface shifts northward, the autumn-winter Correspondence to: P. Prikryl (paul.prikryl@crc.ca) effect weakens or shifts to lower (mid) latitudes and no statistically significant response is found at low latitudes in springsummer. The observed effect persists through years of low and high volcanic aerosol loading. The similarity of the response in mid-to-high and low latitudes, the lack of dependence upon aerosol loading, and the enhanced amplitude of the effect when IMF B Z component shifts southward, favor the proposed AGW link over the atmospheric electric circuit (AEC) mechanism (Tinsley et al., 1994). The latter requires the presence of stratospheric aerosols for a significant effect and should produce negative and positive cloud anomalies in mid-to-high and low latitudes, respectively. However, if the requirement of aerosols for the AEC mechanism can be relaxed, the AGW and AEC mechanisms should work in synergy at least in mid-to-high latitudes.

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Generation of Gravity Waves by Jet Streams in the Atmosphere

Cited by 68 publications

References 0 publications

Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique

Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique

Analysis of the structure and propagation of a simulated squall line on 14 June 2009

The influence of solar wind on extratropical cyclones – Part 2: A link mediated by auroral atmospheric gravity waves?

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