Wind and Temperature Oscillations Generated by Wave–Turbulence Interactions in the Stably Stratified Boundary Layer

Sun, Jielun; Mahrt, L.; Nappo, Carmen J.; Lenschow, Donald H.

doi:10.1175/jas-d-14-0129.1

Cited by 97 publications

(104 citation statements)

References 90 publications

(82 reference statements)

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“…In fact, wind speed perturbations induced by waves can enhance shear and thereby promote the onset of mechanically generated turbulence (orange whirls in Figure 4), which then also affects heat transport [186,200]. Actually, intermittent turbulence can be triggered in the SBL by a range of diverse sub-mesoscale (submeso) motions, of which orographically generated IGW are just one example [194,[201][202][203].…”

Section: The Role Of Gravity Wavesmentioning

confidence: 99%

Exchange Processes in the Atmospheric Boundary Layer Over Mountainous Terrain

et al. 2018

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Abstract:The exchange of heat, momentum, and mass in the atmosphere over mountainous terrain is controlled by synoptic-scale dynamics, thermally driven mesoscale circulations, and turbulence. This article reviews the key challenges relevant to the understanding of exchange processes in the mountain boundary layer and outlines possible research priorities for the future. The review describes the limitations of the experimental study of turbulent exchange over complex terrain, the impact of slope and valley breezes on the structure of the convective boundary layer, and the role of intermittent mixing and wave-turbulence interaction in the stable boundary layer. The interplay between exchange processes at different spatial scales is discussed in depth, emphasizing the role of elevated and ground-based stable layers in controlling multi-scale interactions in the atmosphere over and near mountains. Implications of the current understanding of exchange processes over mountains towards the improvement of numerical weather prediction and climate models are discussed, considering in particular the representation of surface boundary conditions, the parameterization of sub-grid-scale exchange, and the development of stochastic perturbation schemes.

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Section: The Role Of Gravity Wavesmentioning

confidence: 99%

Exchange Processes in the Atmospheric Boundary Layer Over Mountainous Terrain

et al. 2018

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“…The energy and momentum transported by GWs can be transferred to the mean flow, influencing local meteorology and global atmospheric circulations [10]. Moreover, instability and breaking of waves can produce clear air turbulence in the troposphere and can generate turbulence in the SBL that enhances the intermittent characteristics of turbulent transport of momentum, mass and energy [17]. The latter influences chemical mixing of aerosols, biogenic and anthropogenic gases.…”

Section: Introductionmentioning

confidence: 99%

“…While some progress has been made in the GW parameterisation within global models, description and parameterisation of the turbulence-wave interaction remain an open question, especially near the ground [17][18][19][20]. The discrimination between waves and turbulence is a focal point needed to make progress as these two motions have different properties with regards to heat, moisture and pollutant transport.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Gravity Waves over an Antarctic Ice Sheet during an Austral Summer

2015

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While occurrences of wavelike motion in the stable boundary layer due to the presence of a significant restoring buoyancy force are rarely disputed, their modalities and interaction with turbulence remain a subject of active research. In this work, the characteristics of gravity waves and their impact on flow statistics, including turbulent fluxes, are presented using data collected above an Antarctic Ice sheet during an Austral Summer. Antarctica is an ideal location for exploring the characteristics of gravity waves because of persistent conditions of strong atmospheric stability in the lower troposphere. Periods dominated by wavelike motion have been identified by analysing time series measured by fast response instrumentation. The nature and characteristic of the dominant wavy motions are investigated using Fourier cross-spectral indicators. Moreover, a multi-resolution decomposition has been applied to separate gravity waves from turbulent fluctuations in case of a sufficiently defined spectral gap. Statistics computed after removing wavy disturbances highlight the large impact of gravity waves on second order turbulent quantities including turbulent flux calculations. OPEN ACCESSAtmosphere 2015, 6 1272

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“…Although these phenomena are common in SBLs, it is not easy to find clear evidence of their existence given the fine horizontal and vertical resolutions required for such observations. Thus, only a few studies have reported in detail cases like the one here presented, as for example in Sun et al (2015a).…”

Section: Introductionmentioning

confidence: 83%

Interactions among drainage flows, gravity waves and turbulence: a BLLAST case study

et al. 2015

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Abstract. The interactions among several stable-boundarylayer (SBL) processes occurring just after the evening transition of 2 July 2011 have been analysed using data from instruments deployed over the area of Lannemezan (France) during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign. The near-calm situation of the afternoon was followed by the formation of local shallow drainage flows (SDFs) of less than 10 m depth at different locations. The SDF stage ended with the arrival of a stronger wind over a deeper layer more associated with the mountain-plain circulation, which caused mixing and destruction of the SDFs. Several gravity-wave-related oscillations were also observed on different time series. Wavelet analyses and wave parameters were calculated from high resolution and accurate surface pressure data of an array of microbarometers. These waves propagated relatively long distances within the SBL. The effects of these phenomena on turbulent parameters (friction velocity and kinematic heat flux) have been studied through multi-resolution flux decomposition methods performed on high frequency data from sonic anemometers deployed at different heights and locations. With this method, we were able to detect the different time-scales involved in each turbulent parameter and separate them from wave contributions, which becomes very important when choosing averaging-windows for surface flux computations using eddy covariance methods. The extensive instrumentation allowed us to highlight in detail the peculiarities of the surface turbulent parameters in the SBL, where several of the noted processes were interacting and producing important variations in turbulence with height and between sites along the sloping terrain.

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Wind and Temperature Oscillations Generated by Wave–Turbulence Interactions in the Stably Stratified Boundary Layer

Cited by 97 publications

References 90 publications

Exchange Processes in the Atmospheric Boundary Layer Over Mountainous Terrain

Exchange Processes in the Atmospheric Boundary Layer Over Mountainous Terrain

Characteristics of Gravity Waves over an Antarctic Ice Sheet during an Austral Summer

Interactions among drainage flows, gravity waves and turbulence: a BLLAST case study

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