Forcing of secondary waves by breaking of gravity waves in the mesosphere

Zhou, Xuelong; Holton, James R.; Mullendore, G. L.

doi:10.1029/2001jd001204

Cited by 33 publications

(53 citation statements)

References 15 publications

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“…Here we find that the breaking region starts above the stratopause and extends well into the MLT. Our finding is consistent with previous theoretical studies (e.g., Holton and Alexander, 1999;Zhou et al, 2002;Vadas and Crowley, 2010).…”

Section: Boreal Summersupporting

confidence: 83%

“…For example, and have demonstrated the global importance of GWs of lower atmospheric origin in the energy and momentum budget of the thermosphere. There are also other model studies, which suggest that breaking of primary GWs can generate secondary GWs and these secondary GWs in turn can propagate up to the thermosphere (e.g., Zhou et al, 2002;Liu, 2009, 2013;Vadas and Crowley, 2010;Vadas, 2013;Vadas et al, 2014).…”

Section: Summary and Discussionmentioning

confidence: 99%

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Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves

et al. 2018

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Abstract. Atmospheric gravity waves (GWs) are essential for the dynamics of the middle atmosphere. Recent studies have shown that these waves are also important for the thermosphere/ionosphere (T/I) system. Via vertical coupling, GWs can significantly influence the mean state of the T/I system. However, the penetration of GWs into the T/I system is not fully understood in modeling as well as observations. In the current study, we analyze the correlation between GW momentum fluxes observed in the middle atmosphere (30-90 km) and GW-induced perturbations in the T/I. In the middle atmosphere, GW momentum fluxes are derived from temperature observations of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite instrument. In the T/I, GW-induced perturbations are derived from neutral density measured by instruments on the Gravity field and Ocean Circulation Explorer (GOCE) and CHAllenging Minisatellite Payload (CHAMP) satellites. We find generally positive correlations between horizontal distributions at low altitudes (i.e., below 90 km) and horizontal distributions of GW-induced density fluctuations in the T/I (at 200 km and above). Two coupling mechanisms are likely responsible for these positive correlations: (1) fast GWs generated in the troposphere and lower stratosphere can propagate directly to the T/I and (2) primary GWs with their origins in the lower atmosphere dissipate while propagating upwards and generate secondary GWs, which then penetrate up to the T/I and maintain the spatial patterns of GW distributions in the lower atmosphere. The mountain-wave related hotspot over the Andes and Antarctic Peninsula is found clearly in observations of all instruments used in our analysis. Latitude-longitude variations in the summer midlatitudes are also found in observations of all instruments. These variations and strong positive correlations in the summer midlatitudes suggest that GWs with origins related to convection also propagate up to the T/I. Different processes which likely influence the vertical coupling are GW dissipation, possible generation of secondary GWs, and horizontal propagation of GWs. Limitations of the observations as well as of our research approach are discussed.

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Section: Boreal Summersupporting

confidence: 83%

Section: Summary and Discussionmentioning

confidence: 99%

Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves

et al. 2018

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“…It is also likely that the observed GWs in these cases (G3, G4, G5, H5 and H7) are from secondary wave generation due to wave breaking at the termination region. While secondary wave generation due to convectively generated waves has been investigated (e.g., Zhou et al, 2002;Chun and Kim, 2008), such investigations have not yet been carried out for GWs of shear origin. This aspect needs further investigation.…”

Section: Discussionmentioning

confidence: 99%

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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“…14a-14c. The waves with horizontal wavelengths much smaller than those below z 5 12 km are the secondary waves, and there have been several numerical modeling studies on this topic associated with mountain waves (e.g., Bacmeister and Schoeberl 1989;Satomura and Sato 1999) and convective gravity waves (e.g., Holton and Alexander 1999;Zhou et al 2002;Snively and Pasko 2003;Lane and Sharman 2006;Chun and Kim 2008).…”

Section: Eastern Mountain Areamentioning

confidence: 99%

A Numerical Study of Clear-Air Turbulence (CAT) Encounters over South Korea on 2 April 2007

Kim

Chun

2010

Journal of Applied Meteorology and Climatology

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On 2 April 2007, nine cases of moderate-or-greater-level clear-air turbulence (CAT) were observed from pilot reports over South Korea during the 6.5 h from 0200 to 0830 UTC. Those CAT events occurred in three different regions of South Korea: the west coast, Jeju Island, and the eastern mountain areas. The characteristics and possible mechanisms of the CAT events in the different regions are investigated using the Weather Research and Forecasting model. The simulation consists of six nested domains focused on the Korean Peninsula, with the finest horizontal grid spacing of 0.37 km. The simulated wind and temperature fields in a 30-km coarse domain are in good agreement with those of the Regional Data Assimilation and Prediction System (RDAPS) analysis data of the Korean Meteorological Administration and observed soundings of operational radiosondes over South Korea. In synoptic features, an upper-level front associated with strong meridional temperature gradients is intensified, and the jet stream passing through the central part of the Korean Peninsula exceeds 70 m s 21 . Location and timing of the observed CAT events are reproduced in the finest domains of the simulated results in three different regions. Generation mechanisms of the CAT events revealed in the model results are somewhat different in the three regions. In the west coast area, the tropopause is deeply folded down to about z 5 4 km because of the strengthening of an upper-level front, and the maximized vertical wind shear below the jet core produces localized turbulence. In the Jeju Island area, localized mixing and turbulence are generated on the anticyclonic shear side of the enhanced jet, where inertial instability and ageostrophic flow are intensified in the lee side of the convective system. In the eastern mountain area, large-amplitude gravity waves induced by complex terrain propagate vertically and subsequently break down over the lee side of topography, causing localized turbulence. For most of the CAT processes considered, except for the mountain-wave breaking, standard NWP resolutions of tens of kilometers are adequate to capture the CAT events.

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Forcing of secondary waves by breaking of gravity waves in the mesosphere

Cited by 33 publications

References 15 publications

Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves

Satellite observations of middle atmosphere–thermosphere vertical coupling by gravity waves

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

A Numerical Study of Clear-Air Turbulence (CAT) Encounters over South Korea on 2 April 2007

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