Statistics of Turbulence in the Stable Boundary Layer Affected by Gravity Waves

Abstract

In order to investigate effects of interactions between turbulence and gravity waves in the stable boundary layer on similarity theory relationships, we re-examined a dataset, collected during three April nights in 1978 and in 1980 on the 300-m tower of the Boulder Atmospheric Observatory (BAO). The BAO site, located in Erie, Colorado, USA, 30 km east of the foothills of the Rocky Mountains, has been known for the frequent detection of wave activities. The considered profiles of turbulent fluxes and variances were normalized by two local, gradient-based scaling systems, and subsequently compared with similarity functions of the Richardson number, obtained based on data with no influence of gravity currents and topographical factors. The first scaling system was based on local values of the vertical velocity variance σ w and the Brunt-Väisäla frequencyN , while the second one was based on the temperature variance σ θ and N . Analysis showed some departures from the similarity functions (obtained for data with virtually no influence of mesoscale motions); nonetheless the overall dependency of dimensionless moments on the Richardson number was maintained.

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

“…On the other hand, the observed 20 % increase in Amazon River discharge may reflect increasing water availability to the vegetation , which together with increasing atmospheric CO 2 may lead to more net carbon uptake by the intact forest vegetation (Schimel et al, 2015). While remote sensing can provide important information on the response of the Amazon forest to changing climate and ecological factors, the recent controversy about the effects of seasonal change and drought on the "greenness" of the forest illustrates how important longterm ground based observations are to our understanding of the Amazon system (Morton et al, 2014;Soudani and Francois, 2014;Zeri et al, 2014).…”

“…Considerable research has also been devoted to the detection of CSs (Collineau and Brunet, 1993;Krusche and Oliveira, 2004) and the dissimilarity between CSs associated with the transport of momentum and scalars (Li and Bou-Zeid, 2011). However, many aspects of their occurrence are still poorly known, particularly: (i) their vertical variability (Lohou et al, 2000); (ii) the manifestations of their interaction with gravity waves (Sorbjan and Czerwinska, 2013); (iii) the influence of surface heterogeneity on their features; (iv) aspects of their numerical simulation (Patton, 1997;Bou-Zeid et al, 2004;Dupont and Brunet, 2009;Wan and Porte-Agel, 2011), particularly in the nocturnal boundary layer (Durden et al, 2013;Zilitinkevich et al, 2013), and (v) implications of the existence of CSs for the chemistry of the atmosphere (Steiner et al, 2011;Foken et al, 2012). A study on the structure of atmospheric turbulence was performed at the ATTO site under daytime conditions, with the aim of contributing to the detection of CSs and developing a better understanding of their vertical and temporal variability over a very uneven terrain covered by primary forest in central Amazonia.…”

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

“…Typical periods of GWs range from a few minutes to approximately one hour, whereas the wavelengths vary from about hundreds of meters to several kilometres [10]. GWs may be generated by several mechanisms, including topographic forcing, dynamical instabilities (i.e., shear instability, microfronts or mesoscale fronts) and wave-wave interactions [11][12][13][14][15].…”

Intermittent turbulence contributes to vertical diffusion of PM<sub>2.5</sub> in the North China Plain

“…Some potential causes include gravity waves (Sorbjan and Czerwinska, 2013;Strang and Fernado, 2001), solitary waves (Terradellas et al, 2005), horizontal meandering of the mean wind field (Anfossi et al, 2005), and low-level jets (LLJs, Marht, 2014).…”