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Boundary-Layer Meteorology
Journal Prestige (SJR): 1.262
Citation Impact (citeScore): 2
Number of Followers: 32  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1573-1472 - ISSN (Online) 0006-8314
Published by Springer-Verlag Homepage  [2469 journals]
  • Diurnal Surface Heating and Roof Material Effects on Urban Pollution
           Dispersion: A Coupled Large-eddy Simulation and Surface Energy Balance
           Analysis

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      Abstract: Abstract We investigate the understudied role of diurnally variable urban surface heating in transport phenomena within an idealized urban environment. We also explore whether heating from different roof materials (asphalt, reflective, and green roofs) at different times of the day affects pollution dispersion and ventilation mechanisms. Results show that the ventilation capacity of urban canyons varies diurnally and is influenced by the buoyancy forces from differentially heated urban surfaces, indicating the highest values in the afternoon and the lowest in the evening. The mechanism of canyon ventilation also varies diurnally. In the morning, the pollutant outflux at the roof level is the principal route of ventilation, while in the evening, lateral outfluxes are dominant and pollutant escape at the roof level is damped because of a local stable air layer. In the afternoon, both vertical and horizontal pollutant outflows contribute similarly to the canyon ventilation. In general, lateral turbulent (rather than mean) fluxes from the side canyon boundaries are the main contributors to the canyon pollutant ventilation throughout the day for all roof-type cases, but their significance slightly decreases from morning to evening. Results reveal that different roof types influence the canyon ventilation mechanism and capacity based on their diurnally-varying surface temperatures and their temperature gradients with respect to other urban surfaces. The existence of the green roof type mainly leads to the generation of a local stable layer and suppression of pollutant escape at the roof level.
      PubDate: 2022-07-01
       
  • Numerical Analysis of the Atmospheric Boundary-Layer Turbulence Influence
           on Microscale Transport of Pollutant in an Idealized Urban Environment

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      Abstract: Abstract The mesoscale atmospheric model Meso-NH is used to investigate the influence of mesoscale atmospheric turbulence on the mean flow, turbulence, and pollutant dispersion in an idealized urban-like environment, the array of containers investigated during the Mock Urban Setting Test field experiment. First, large-eddy simulations are performed as in typical computational fluid dynamics-like configurations, i.e., without accounting for the atmospheric- boundary-layer (ABL) turbulence on scales larger than the building scale. Second, in a multiscale configuration, turbulence of all scales prevailing in the ABL is accounted for by using the grid-nesting approach to downscale from the mesoscale to the microscale. The building-like obstacles are represented using the immersed boundary method and a new turbulence recycling method is used to enhance the turbulence transition between two nested domains. Upstream of the container array, flow characteristics such as wind speed, direction and turbulence kinetic energy are well reproduced with the multiscale configuration, showing the efficiency of the grid-nesting approach in combination with turbulence recycling for downscaling from the mesoscale to the microscale. Only the multiscale configuration is able to reproduce the mesoscale turbulent structures crossing the container array. The accuracy of the numerical results is evaluated for wind speed, wind direction, and pollutant concentration. The microscale numerical simulation of wind speed and pollutant dispersion in an urban-like environment benefits from taking into account the ABL turbulence. However, this benefit is significantly less important than that described in the literature for the Oklahoma City Joint Urban 2003 real case. The present study highlights that pollutant dispersion simulation improvement when accounting for ABL turbulence is dependent on the specific configuration of the city.
      PubDate: 2022-07-01
       
  • Momentum and Turbulent Transport in Sparse, Organized Vegetative Canopies

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      Abstract: Abstract The effect of canopy heterogeneity on mean and turbulent transport processes is studied using a scaled wind-tunnel model of a vineyard canopy with gap spacings of one, two, and three canopy heights. A row-normal freestream velocity component is applied to each canopy configuration and spatial distributions of velocity across a streamwise-vertical plane centred around a single canopy gap are measured using particle imaging velocimetry. Mean flow features including an updraft in the centre of the canopy followed by a descent and recirculation just upstream of the downstream row are observed to decrease in size and magnitude for larger canopy gaps. Turbulence in the canopy sublayer (CSL) is dominated by a growing mixing layer that originates at the top of the upstream row and consumes the underlying weak more isotropic turbulence. The mixing layer’s rate of growth into the CSL decreases as the canopy gap widens, but not enough to offset the increased downstream distance. The vertical extent of the mixing layer into the canopy before being impeded by the downstream row is the main factor that determines horizontal heterogeneity of turbulence in the canopy. An analysis of the Reynolds-averaged turbulence-kinetic-energy budget points to shear production being the main source of turbulence near the canopy top, while turbulent transport is responsible for the growth of the mixing layer down into the CSL.
      PubDate: 2022-07-01
       
  • On the Non-monotonic Variation of the Entrainment Buoyancy Flux with Wind
           Shear

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      Abstract: Abstract The magnitude of the entrainment buoyancy flux, and hence the growth rate of the convective boundary layer, does not increase monotonically with wind shear. Explanations for this have previously been based on wind-shear effects on the turbulence kinetic energy. By distinguishing between turbulent and non-turbulent regions, we provide an alternative explanation based on two competing wind-shear effects: the initial decrease in the correlation between buoyancy and vertical velocity fluctuations, and the increase in the turbulent area fraction. The former is determined by the change in the dominant forcing; without wind shear, buoyancy fluctuations drive vertical velocity fluctuations and the two are thus highly correlated; with wind shear, vertical velocity fluctuations are partly determined by horizontal velocity fluctuations via the transfer of kinetic energy through the pressure–strain correlation, thus reducing their correlation with the buoyancy field. The increasing turbulent area fraction, on the other hand, is determined by the increasing shear production of turbulence kinetic energy inside the entrainment zone. We also show that the dependence of these conditional statistics on the boundary-layer depth and on the magnitude of the wind shear can be captured by a single non-dimensional variable, which can be interpreted as an entrainment-zone Froude number.
      PubDate: 2022-06-21
       
  • Types of Vertical Structure of the Nocturnal Boundary Layer

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      Abstract: Abstract The vertical structure of the observed stable boundary layer often deviates substantially from textbook profiles. Even over flat homogeneous surfaces, the turbulence may not be completely related to the surface conditions and instead generated by elevated sources of turbulence such as low-level jets and transient modes. In stable conditions, even modest surface heterogeneity can alter the vertical structure of the stable boundary layer. With clear skies and low wind speeds, cold-air drainage is sometimes generated by very weak slopes and induces a variety of different vertical structures. Our study examines the vertical structure of the boundary layer at three contrasting tower sites. We emphasize low wind speeds with strong stratification. At a given site, the vertical structure may be sensitive to the surface wind direction. Classification of vertical structures is posed primarily in terms of the profile of the heat flux. The nocturnal boundary layer assumes a variety of vertical structures, which can often be roughly viewed as layering of the heat-flux divergence (convergence). The correlation coefficient between the temperature and vertical velocity fluctuations provides valuable additional information for classification of the vertical structure.
      PubDate: 2022-06-16
       
  • On the Lagrangian and Eulerian Time Scales of Turbulence Within a
           Two-Dimensional Array of Obstacles

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      Abstract: Abstract Fields of Lagrangian ( \(T^{L}\) ) and Eulerian ( \(T^{E}\) ) time scales of the turbulence within a regular array of two-dimensional obstacles of unit aspect ratio have been determined by means of a water-channel experiment reproducing the atmospheric boundary layer in neutral conditions. It has been found that there is a strong spatial inhomogeneity both of the scales and of their ratio, \(\beta = T^{L} /T^{E}\) . The results can provide useful information on numerical modelling of tracer dispersion in urban areas.
      PubDate: 2022-06-15
       
  • Celebrating the Career of Dr. John R. Garratt: Long-Term Proponent of
           Boundary-Layer Meteorology and International Man of Mystery

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      PubDate: 2022-06-10
       
  • A Predictive Method for Estimating Space–Time Correlations in the
           Atmospheric Surface Layer

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      Abstract: Abstract Space–time correlations are fundamental to statistical theories and turbulence modelling. However, experimental studies of space–time correlations are often restricted to the requirements of high spatially- and temporally-resolved data, especially in the atmospheric surface layer (ASL). In this study, based on the simultaneous multipoint temperature fluctuations measured at different streamwise positions with the application of distributed temperature sensing, the longitudinal space–time correlations of temperature fluctuations (CTT(r, τ)) were directly measured in the near-neutral, unstable, and stable ASL. Our results show that, unlike Taylor’s frozen turbulence hypothesis, the elliptic model can relate the space–time correlation CTT(r, τ) to space correlation (CTT(rE, 0)) in the ASL, where rE = ((r − Ueτ)2 + (Veτ)2)1/2, Ue is the convection velocity, and Ve is the sweeping velocity. Furthermore, we also provide a predictive method for estimating CTT(r, τ) in the ASL based on the elliptic model. With the application of our new method, CTT(r, τ) can be estimated from one-point measurements in the near-neutral, unstable, and stable ASL by using Ue and Ve, and the predicted CTT(r, τ) is similar to the directly measured results. This indicates that our method can be used to reconstruct CTT(r, τ) in the ASL.
      PubDate: 2022-06-07
       
  • On the Influence of Large-Scale Atmospheric Motions on Near-Surface
           Turbulence: Comparison Between Flows Over Low-Roughness and Tall
           Vegetation Canopies

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      Abstract: Abstract Contrary to Monin–Obukhov similarity theory, near-surface atmospheric turbulence depends not only on local motions but also on larger-scale motions associated with the full atmospheric boundary layer (ABL), where they themselves evolve in character with thermal stratification. After reviewing our current knowledge of ABL motions, we present wavelet velocity and air temperature spectra for both eddy-surface-layer (ESL) flows above rough surfaces and roughness-sublayer (RSL) flows above vegetation canopies, both flows characterizing turbulence over two scales of land roughness. Spectra are extended to the production scale to identify the influence of ABL-scale motions following the thermal stratification. Contrary to turbulence in the ESL, RSL turbulence appears weakly enhanced by ABL-scale motions in near-neutral regimes. With increasing influence of buoyancy, ABL-scale motions play a larger role in ESL and RSL flows, dominating the locally produced turbulence in free convection, while acting to decouple local from the large-scale motions in the stable regime. The behaviour of ESL and RSL spectra with stability variations support the view of, (1) canopy-scale eddies dominating the canopy turbulence over the larger ABL-scale motions in windy conditions, (2) ABL-scale motions known as very-large-scale motions (VLSMs) influencing the ESL horizontal velocity turbulence in windy conditions, and (3) the progressive transitioning of ABL-scale motions from VLSMs to thermals with instability in ESL flows. The direct contribution of ABL-scale motions to near-surface momentum and heat turbulent fluxes appears small. Finally, near-surface velocity spectra are well-approximated as a linear superposition of individual spectra associated to the main eddies populating the flow.
      PubDate: 2022-06-06
       
  • Turbulence characteristics within the atmospheric surface layer of the
           coastal region of Qatar

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      Abstract: Abstract The atmospheric turbulence characteristics in the coastal region of Qatar are analyzed using the measurements conducted on the shoreline (26.08 N, 51.36 E). The micrometeorological data were collected, from August 2015 to September 2016, using sonic anemometers (20 Hz) at three heights and a weather station atop a 9-m tower. The turbulence characteristics are studied within the framework of Monin–Obukhov similarity theory (MOST), in the presence of the coastal inhomogeneities generated by the sea and land surfaces coming together. The results show the wind from the north-west prevails during the entire test period, with the wind speed higher than that from other directions. The non-dimensional standard deviations of velocity components are found to be consistent the results reported around the world and match suggested MOST scaling, with a relatively greater value for the dissipation rate of turbulent kinetic energy. The flux Richardson number shows a larger scatter under the super-stable and super-unstable regimes. Moreover, the non-dimensional standard deviation of temperature does not align with the suggested model under near-neutral and very stable regimes, and the gradient Richardson number shows some negative values under stable regimes. Two different atmospheric daily stability patterns, ‘orderly’ and ‘disheveled,’ are identified based on the wind conditions. The orderly stability pattern shows a daily descending and ascending trend during the sunrise and sunset periods, respectively, while the disheveled days follow a random pattern with no clear order. The two patterns are then related to the wind continuity and direction relative to the shoreline.
      PubDate: 2022-06-03
       
  • Unique Windward Measurements and a Mesoscale Simulation of an Extremely
           Long-Lasting Severe Bora Event

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      Abstract: Abstract Unique data from a 100-m meteorological mast located on the windward side of the Dinaric Alps, Croatia, are compared to high-resolution Weather Research and Forecasting (WRF) model simulations. This was performed for an especially strong and long-lasting (more than 20 days) wintertime bora event. The agreement between the measurements on the mast and the respective WRF simulation was generally very good, even with respect to the time series of the turbulence kinetic energy. Based on this finding, which validates the WRF model suitability for numerical simulations of transient winds in windward areas, this approach can be used in future studies to explore the severe bora upwind of the coastal mountains, which has been studied inadequately thus far. In this context, some of the preliminary results are outlined here.
      PubDate: 2022-06-01
       
  • Impacts of Boundary-Layer Structure and Turbulence on the Variations of
           PM2.5 During Fog–Haze Episodes

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      Abstract: Abstract The precise cause of PM2.5 (fine particular matter with a diameter smaller than 2.5 μm) explosive growth and the contribution of intermittent turbulence to the dispersion of PM2.5 are uncertain. Thus, the impact of boundary-layer structure and turbulence on the variations of surface PM2.5 during fog–haze episodes, especially during explosive growth and dispersion episodes, are investigated using turbulence data collected at a 255-m high meteorological tower in Tianjin from 2016 to 2018. Results suggest that the explosive growth of surface PM2.5 during fog–haze episodes is closely related to weak turbulent mixing, nocturnal inversions, or anomalous inversions, and the barrier effect of strong turbulent intermittency. Turbulent intermittency acts as a lid for hindering pollutant dispersion and is favourable for the fast accumulation of surface PM2.5. Apart from the potential causes mentioned above, the persistent moderate south-westerly flow is also a contributing factor for the explosive growth of surface PM2.5 during fog–haze episodes associated with regional transport. In addition, we demonstrate a possible mechanism of how intermittent turbulence affects the dispersion of PM2.5. Results verify that intermittent turbulence induced by the nocturnal low-level jet (LLJ) indeed plays an important role in the dispersion of PM2.5. However, the contribution of intermittent turbulence generated by the nocturnal LLJ to the dispersion of PM2.5 strongly relies on the intensity of the nocturnal LLJ.
      PubDate: 2022-06-01
       
  • A Case Study of the Weather Research and Forecasting Model Applied to the
           Joint Urban 2003 Tracer Field Experiment. Part III: Boundary-Layer
           Parametrizations

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      Abstract: Abstract Numerical weather prediction is often used to supply the mean wind and turbulence fields for atmospheric transport and dispersion plume models as they provide dense geographic coverage in comparison to typically sparse monitoring networks. Here, the Weather Research and Forecasting (WRF) model 4.0 was run over the month-long period of the Joint Urban 2003 field campaign conducted in Oklahoma City. We compare three different simulations in their ability to reproduce the observations, each using a different boundary-layer parametrization. Specifically, we examine the Mellor–Yamada–Janjic (MYJ), Yonsei University (YSU), and Mellor–Yamada–Nakanishi–Niino (MYNN) boundary-layer parametrizations. All three predict the wind speed well during the day but overpredict it at night. The MYNN parametrization is better than MYJ at predicting the daytime turbulence in the surface layer, but both underpredict the nocturnal turbulence. The MYJ parametrization is best at predicting the reciprocal Obukhov length, while MYNN and YSU both significantly overpredict thermal stability. Reconstructing the reciprocal Obukhov length from other simulated parameters produces more accurate values for both parametrizations. All three models overpredict the boundary-layer height, particularly under convective conditions. The MYJ parametrization overestimates boundary-layer height the most, while YSU and MYNN have comparable performance with MYNN having an advantage in predicting the stable boundary-layer height. Several days were found where the WRF simulations predict significant deviations from the prevailing diurnal pattern in wind direction, which are not found in the observations.
      PubDate: 2022-06-01
       
  • A Ship-Based Characterization of Coherent Boundary-Layer Structures Over
           the Lifecycle of a Marine Cold-Air Outbreak

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      Abstract: Abstract Convective coherent structures shape the atmospheric boundary layer over the lifecycle of marine cold-air outbreaks (CAOs). Aircraft measurements have been used to characterize such structures in past CAOs. Yet, aircraft case studies are limited to snapshots of a few hours and do not capture how coherent structures, and the associated boundary-layer characteristics, change over the CAO time scale, which can be on the order of several days. We present a novel ship-based approach to determine the evolution of the coherent-structure characteristics, based on profiling lidar observations. Over the lifecycle of a multi-day CAO we show how these structures interact with boundary-layer characteristics, simultaneously obtained by a multi-sensor set-up. Observations are taken during the Iceland Greenland Seas Project’s wintertime cruise in February and March 2018. For the evaluated CAO event, we successfully identify cellular coherent structures of varying size in the order of 4  \(\times \)  10 \(^2\)  m to 10 \(^4\)  m and velocity amplitudes of up to 0.5 m  \(\hbox {s}^{-1}\) in the vertical and 1 m  \(\hbox {s}^{-1}\) in the horizontal. The structures’ characteristics are sensitive to the near-surface stability and the Richardson number. We observe the largest coherent structures most frequently for conditions when turbulence generation is weakly buoyancy dominated. Structures of increasing size contribute efficiently to the overturning of the boundary layer and are linked to the growth of the convective boundary-layer depth. The new approach provides robust statistics for organized convection, which would be easy to extend by additional observations during convective events from vessels of opportunity operating in relevant areas.
      PubDate: 2022-06-01
       
  • An Iterative Method for Calculation of Wind Profiles at the Mesoscale and
           Microscale

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      Abstract: Abstract This paper presents the variational diagnostic model and iterative procedure, which enables the wind field in subdomains to be adjusted. Diagnostic models are not time dependent. Consideration of more complex features of the thermodynamic structure requires models with high resolution, which require large calculation times. The model presented applies the variational approach and enables topographical complexity of the terrain to be considered. The problem of adjusting the wind field is solved in two steps. The first step adjusts the initial wind field by means of experimental measurements or a prognosis in the larger domain, which includes smaller domains. Then the results obtained are used as the initial wind field when the grid refinement in the smaller domain is performed. This allows more precise mapping of the terrain and its architecture. Nevertheless the algorithm proposed ensures a considerable reduction in calculation time. This approach also allows us to eliminate the problem of the lack of initial data when the number of meteorological stations in the smaller domain is insufficient. The algorithm is described and validated, and numerical simulations for pollutant dispersion for a chosen town are described, followed by discussion of the iterative procedure.
      PubDate: 2022-06-01
       
  • Hysteresis and Surface Shear Stresses During Snow-Particle Aeolian
           Transportation

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      Abstract: Abstract Surface shear stresses produced by wind and particle collision play a key role in aerodynamic entrainment and splash processes. The fluid shear stress at the surface during aeolian transport has been researched for decades; however, the equilibrium property reported in the literature, numerical simulations, and experiments is inconsistent. To discuss this discrepancy, this study investigates fluid and particle shear stresses at the surface during the aeolian transport of snow particles using a two-dimensional random-flight model of drifting snow. The simulations are performed for various friction velocities on a loose snow bed. By varying the wind conditions in stages, the transport hysteresis is confirmed, and the impact threshold is estimated from the particle transport rate ( \(0.206\,\hbox {m\,s}^{-1}\) ). The friction velocity at the surface during transport decreases marginally with an increase in wind speed caused by the impact threshold, revealing that our results do not contradict Owen’s second hypothesis. The total shear stress, which is calculated by summing the fluid and particle shear stresses, is vertically uniform in the equilibrium state; thus, the increase in the particle shear stress decreases the fluid shear stress at the surface. The equilibrium property of the fluid shear stress near the surface changes significantly with height (from a decreasing trend to an increasing trend) because the particle shear stress decreases rapidly in the height range of 1–10 mm. Our findings suggest that it is difficult to accurately measure the fluid shear stress in the surface vicinity using anemometers, and a new methodology is needed.
      PubDate: 2022-06-01
       
  • Integrated Quadrant Analysis: A New Method for Analyzing Turbulent
           Coherent Structures

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      Abstract: Abstract Integrated quadrant analysis is a novel technique to identify and to characterize the trajectory and strength of turbulent coherent structures in the atmospheric surface layer. By integrating the three-dimensional velocity field characterized by traditional quadrant analysis with respect to time, the trajectory history of individual coherent structures can be preserved with Eulerian turbulence measurements. We develop a method to identify the ejection phase of coherent structures based on turbulence kinetic energy (TKE). Identifying coherent structures within a time series using TKE performs better than identifying them with the streamwise and vertical velocity components because some coherent structures are dominated by the cross-stream velocity component as they pass the sensor. By combining this identification method with the integrated quadrant analysis, one can animate or plot the trajectory of individual coherent structures from high-frequency velocity measurements. This procedure links a coherent ejection with the subsequent sweep and quiescent period in time to visualize and quantify the strength and the duration of a coherent structure. We develop and verify the method of integrated quadrant analysis with data from two field studies: the Eclipse Boundary Layer Experiment (EBLE) in Corvallis, Oregon in August 2017 (grass field) and the Vertical Cherry Array Experiment (VACE) in Linden, California in November 2019 (cherry orchard). The combined TKE identification method and integrated quadrant analysis are promising additions to conditional sampling techniques and coherent structure characterization because the identify coherent structures and couple the sweep and ejection components in space. In an orchard (VACE), integrated quadrant analysis verifies each coherent structure is dominated by a sweep. Conversely, above the roughness sublayer (EBLE), each coherent structure is dominated by an ejection.
      PubDate: 2022-05-14
       
  • Modification of a Wavelet-Based Method for Detecting Ebullitive Methane
           Fluxes in Eddy-Covariance Observations: Application at Two Rice Fields

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      Abstract: Abstract Ebullition, the release of gas bubbles, is an important pathway of methane emission in many ecosystems, yet its high spatio–temporal variability makes it challenging to quantify. In this work, a methane-flux partitioning method based on scalar similarity in the wavelet domain is applied to eddy-covariance data collected at two flooded rice fields. Inspection of initial results indicates that several modifications are needed for robust ebullition detection. With these modifications, our objectives are to compare the original and modified methods, conduct a sensitivity analysis of the program’s empirical parameters, characterize the importance of ebullition in rice across growth stages, and identify the primary drivers of ebullition. The modified method’s ebullitive fluxes are significantly lower and show lower variance than those from the original method. Furthermore, the two methods produce distinct patterns of diel variation. While partitioning estimates show non-trivial sensitivity to the program parameters, this sensitivity is lower in magnitude than the random error in the ebullitive flux estimates. Ebullitive fluxes make up 9% of the total flux on average, with ebullition increasing in importance as plants develop. Ebullitive fluxes are best predicted by wind speed (negative effect), ecosystem respiration (positive effect), and sensible heat flux (positive effect), suggesting an indirect effect of plant-mediated transport, a link with temperature and methane production, and a potential effect of water column turnover, respectively. In addition to validating the method with independent ebullition observations, we recommend its application at more natural and managed wetlands to improve understanding of this highly variable transport pathway.
      PubDate: 2022-04-30
       
  • Large-Eddy Simulation of the Atmospheric Boundary Layer with Near-Wall
           Resolved Turbulence

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      Abstract: Abstract In this study, a large-eddy simulation (LES) code with the one-dimensional turbulence (ODT) wall model is tested for the simulation of the atmospheric boundary layer under neutral, stable, unstable and free-convection conditions. The ODT model provides a vertically refined flow field near the wall, which has small-scale fluctuations from the ODT stochastic turbulence model and an extension of the LES large-scale coherent structures. From this additional field, the lower boundary conditions needed by LES can be extracted. Results are compared to the LES using the classical algebraic wall model based on the Monin–Obukhov similarity theory (MOST), showing similar results in most of the domain with improvements in horizontal velocity and temperature spectra in the near-wall region for simulations of the neutral/stable/unstable cases. For the free-convection test, spectra from the ODT part of the flow were directly compared to spectra generated by LES-MOST at the same height, showing similar behaviour despite some degradation. Furthermore, the additional flow field improved the near-wall vertical velocity skewness for the unstable/free-convection cases. The tool is demonstrated to provide adequate results without the need of any case-specific parameter tuning. Future studies involving complex physicochemical processes at the surface (such as the presence of vertically distributed sources and sinks of matter and energy) within a large domain are likely to benefit from this tool.
      PubDate: 2022-04-26
       
  • A Methodology for Providing Surface-Cover-Corrected Net Radiation at
           Heterogeneous Eddy-Covariance Sites

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      Abstract: Abstract A one-point measurement of net radiation is typically not representative of radiative energy available for the turbulent exchange of latent and sensible heat at eddy-covariance sites with heterogeneous surface cover. We propose a methodology for providing surface-cover-corrected net radiation matching the footprint of turbulent fluxes at a heterogenous eddy-covariance site. This is demonstrated at a complex sub-alpine site in southern central Norway over a week. The methodology is assessed by comparing the energy balance closure calculated with the regular one-point net radiation measurement at the flux tower against the surface-cover-corrected net radiation. The assessment indicates a decrease in the energy imbalance by 8% when assessed with the energy balance ratio, but no improvement is revealed when assessed with regression methods. However, only a small dataset serves as basis for this demonstration, and the findings therefore cannot necessarily be generalized. Further testing and application of the methodology is required to understand the full effect of surface-cover-correcting mismatching footprints of turbulent fluxes and net radiation at heterogeneous eddy-covariance sites.
      PubDate: 2022-04-23
       
 
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