Flux Similarity and Turbulent Transport of Momentum, Heat and Carbon Dioxide in the Urban Boundary Layer

Schmutz, Michael; Vogt, Roland

doi:10.1007/s10546-019-00431-w

Cited by 18 publications

(15 citation statements)

References 42 publications

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“…3). These kinds of bursts in the scalar fluxes, found for the first regime, are regarded as a prevalent feature of convective turbulence [14,4,18,28,11]. Nevertheless, in the second regime, the bursts become exceedingly rare for w T (Fig.…”

Section: Heat and Moisture Fluxesmentioning

confidence: 89%

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

2021

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The ramifications of gust-front on atmospheric surface layer (ASL) turbulence is a vexing issue, with nearly no information available over the Indian region where such events are not uncommon. Over the Indian peninsula, Chowdhuri et al. (Environ. Fluid Mech. 21(1):263-281, 2021) have shown that, the cold pool associated with the gust-front creates two distinct regimes in ASL turbulence, where the temperature fluctuations display contrasting behavior. To evaluate the corresponding impacts on the moisture fluctuations and turbulent heat and moisture transport, we extend our analysis by using the same field-experimental dataset of Chowdhuri et al. (2021). We discover that, the topology of the turbulent structures which govern the temperature and moisture fluctuations clearly exhibit a regime-wise distinction. In the first regime, the structures in temperature and moisture fluctuations are significantly inclined in the vertical, while demonstrating a self-similarity in their time scales by being related through a power-law distribution. However, in the second regime, the vertical inclination disappears for the temperature structures with hardly any change observed for the moisture. Moreover, the power-law exponents of the turbulent temperature time scales remain sensitive to the regimes, although no such effect is visible in the power-law character of the moisture time scales. Additionally, the dissimilarity in the heat and moisture transport is investigated through a novel polar-quadrant based approach that separates the phases and amplitudes of the flux-transporting motions.

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Section: Heat and Moisture Fluxesmentioning

confidence: 89%

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

2021

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“…The validity of MOST is based on an idealized assumption, known as Reynolds analogy, which assumes that momentum and scalars (and different scalars) are transported similarly by turbulent eddies. However, numerous studies have identified that the transport dissimilarity of momentum, heat, and other scalars substantially challenges the performance of MOST (Lamaud and Irvine, 2006; Li and Bou‐Zeid, 2011; Larsén et al ., 2014; Gao et al ., 2018; Li, 2019; Schmutz and Vogt, 2019). For instance, the correlation coefficient between momentum and kinematic heat flux (i.e.,

R_{wu, wT} = \frac{\overset{((), w^{'} u^{'} - \overset{w^{'} u^{'}}{true}) ((), w^{'} T^{'} - \overset{w^{'} T^{'}}{true})}{true}}{σ_{w^{'} u'} σ_{w^{'} T^{'}}}

, where the superscript prime (i.e.,′) denotes the turbulent fluctuation determined by Reynolds decomposition (e.g.,

u^{'} = u - \overset{true‾}{u}

) varies from 0.2 to 0.7 under the influence of a katabatic flow (Guo et al ., 2022), whereas the counterpart in the urban boundary layer ranges from 0.2 to 0.4, influenced by the atmospheric stability (Schmutz and Vogt, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The validity of MOST is based on an idealized assumption, known as Reynolds analogy, which assumes that momentum and scalars (and different scalars) are transported similarly by turbulent eddies. However, numerous studies have identified that the transport dissimilarity of momentum, heat, and other scalars substantially challenges the performance of MOST (Lamaud and Irvine, 2006;Li and Bou-Zeid, 2011;Larsén et al, 2014;Gao et al, 2018;Li, 2019;Schmutz and Vogt, 2019). For instance, the correlation coefficient between momentum and kinematic heat flux (i.e.,…”

Section: Introductionmentioning

confidence: 99%

“…Given its application in the mitigation and dispersion of air pollution by urban heat islands, turbulent transport of momentum, heat, water vapor, trace gases, and aerosols in the atmospheric boundary layer (ABL), especially in the urban surface layer, has become a hot research topic (Li, 2019;Schmutz and Vogt, 2019;Wang et al, 2019;Ren et al, 2020Ren et al, , 2021. As a useful framework of turbulent-exchange parameterization, Monin-Obukhov similarity theory (MOST) has been widely employed in many of the measurement techniques, as well as in weather and air quality models (Monin and Obukhov, 1954).…”

Section: Introductionmentioning

confidence: 99%

“…, where the superscript prime (i.e., ′ ) denotes the turbulent fluctuation determined by Reynolds decomposition (e.g., u ′ = u − u) varies from 0.2 to 0.7 under the influence of a katabatic flow (Guo et al, 2022), whereas the counterpart in the urban boundary layer ranges from 0.2 to 0.4, influenced by the atmospheric stability (Schmutz and Vogt, 2019).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Decreased dissimilarity of turbulent transport attributed to large eddies

Lan

Wang

Zheng

et al. 2022

Quart J Royal Meteoro Soc

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A number of studies have brought up that turbulent transport dissimilarity between momentum and scalars, and even among scalars, is a distinct feature of the unstable boundary layer, affecting the performance of the Monin-Obukhov similarity theory. Although the source/sink distribution of scalars, as well as the top-down entrainment processes, are identified as being responsible for affecting transport dissimilarity, less is known about the role of bulk-shear-generated non-local large eddies. Using data collected by an eddy covariance system mounted on a 70-m meteorological tower over a complex rural area, decreased transport dissimilarity with enhanced wind shear is observed during daytime unstable conditions, prompting our interest in the underlying governing mechanisms. Enhanced wind shear increases the intensity of coherent large eddies, with spectra analysis confirming that large eddies with scales larger than 0.3 (in the normalized frequency) are mainly responsible for the enhanced correlation of fluxes. Moreover, this process is operating on large eddies with minimal phase differences. With enhanced wind shear, fluctuations of scalars within these non-local large eddies become synchronous. Due to the enhanced ejections of large eddies under strong wind shears, fluxes are transported evenly, thereby resulting in decreased transport dissimilarity.

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Katabatic Flow Structures Indicative of the Flux Dissimilarity for Stable Stratification

Guo

Yang

Gao

et al. 2021

Boundary-Layer Meteorol

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Flux Similarity and Turbulent Transport of Momentum, Heat and Carbon Dioxide in the Urban Boundary Layer

Cited by 18 publications

References 42 publications

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

Decreased dissimilarity of turbulent transport attributed to large eddies

Katabatic Flow Structures Indicative of the Flux Dissimilarity for Stable Stratification

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