A5006744670- Plant Water Relations and Carbon Dynamics
- Meteorological Phenomena and Simulations
- Wind and Air Flow Studies
- Fluid Dynamics and Turbulent Flows
- Climate variability and models
- Atmospheric and Environmental Gas Dynamics
- Atmospheric aerosols and clouds
- Plant responses to elevated CO2
- Spacecraft and Cryogenic Technologies
- Aeolian processes and effects
- Geophysics and Gravity Measurements
- Remote Sensing in Agriculture
- Solar Radiation and Photovoltaics
- Hydrology and Watershed Management Studies
- Calibration and Measurement Techniques
- Urban Heat Island Mitigation
- Atmospheric chemistry and aerosols
- Soil and Unsaturated Flow
- Cyclone Separators and Fluid Dynamics
- Forest ecology and management
- Adaptive optics and wavefront sensing
- Plant Ecology and Soil Science
- Plant Pathogens and Resistance
- Heat Transfer Mechanisms
- Aerodynamics and Fluid Dynamics Research
Wageningen University & Research
2015-2024
Eindhoven University of Technology
1998-2018
J.M. Burgerscentrum
2018
Delft University of Technology
2016-2018
University of Cologne
2018
National Institute of Meteorology
2004-2017
University of Bonn
2008
Abstract. The current version of the Dutch Atmospheric Large-Eddy Simulation (DALES) is presented. DALES a large-eddy simulation code designed for studies physics atmospheric boundary layer, including convective and stable layers as well cloudy layers. In addition, can be used more specific cases, such flow over sloping or heterogeneous terrain, dispersion inert chemically active species. This paper contains an extensive description physical numerical formulation code, gives overview its...
Abstract. Due to the major role of sun in heating earth's surface, atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, period day that connects daytime dry convective night-time stable layer, still has number unanswered scientific questions. This phase cycle challenging from both modelling and observational perspectives: it transitory, most forcings are small or null turbulence regime changes fully convective, close homogeneous...
Abstract In the present work Blackadar’s concept of nocturnal inertial oscillations is extended. describes frictionless above inversion layer. The current includes frictional effects within boundary It shown that wind speed profile an oscillation around equilibrium vector, rather than geostrophic vector (as in Blackadar case). By using this perspective, continuous time-dependent profiles are predicted. As such, information on both height and magnitude low-level jet available as a function...
Abstract The influence of dry‐air entrainment on surface heat fluxes and the convective boundary‐layer (CBL) properties is studied for vegetated land surfaces, using a mixed‐layer CBL model coupled to Penman–Monteith equation under wide range conditions. In order address complex behaviour system, feedback mechanisms involved were put into mathematical framework. Simple expressions evaporative fraction Priestley–Taylor parameter derived, based concept equilibrium evaporation. Dry‐air enhances...
Abstract The collapse of turbulence in the nocturnal boundary layer is studied by means a simple bulk model that describes basic physical interactions surface energy balance. It shown for given mechanical forcing, amount turbulent heat can be transported downward limited to certain maximum. In case weak winds and clear skies, this maximum significantly smaller than net radiative loss minus soil transport. when has low capacity, imbalance generates rapid cooling further suppresses transport,...
Abstract Vegetation and atmosphere processes are coupled through a myriad of interactions linking plant transpiration, carbon dioxide assimilation, turbulent transport moisture, heat atmospheric constituents, aerosol formation, moist convection, precipitation. Advances in our understanding hampered by discipline barriers challenges the role small spatiotemporal scales. In this perspective, we propose to study atmosphere–ecosystem interaction as continuum integrating leaf regional scales...
In this paper a classification of stable boundary layer regimes is presented based on observations near-surface turbulence during the Cooperative Atmosphere–Surface Exchange Study-1999 (CASES-99). It found that different nights can be divided into three subclasses: turbulent regime, an intermittent and radiative which confirms findings two companion papers use simplified theoretical model (it noted its simpliflied structure limits generality to flows). The predict occurrence in terms...
Abstract The mechanism behind the collapse of turbulence in evening as a precursor to onset very stable boundary layer is investigated. To this end cooled, pressure-driven flow investigated by means local similarity model. Simulations reveal temporary whenever surface heat extraction, expressed its nondimensional form h/L, exceeds critical value. As any reduction turbulent friction followed acceleration, long-term state unconditionally turbulent. In contrast, cessation turbulence, which may...
Abstract A conceptual model is used in combination with observational analysis to understand regime transitions of near-surface temperature inversions at night as well Arctic conditions. The combines a surface energy budget bulk parameterization for turbulent heat transport. Energy fluxes or feedbacks due soil and radiative transfer are accounted by “lumped parameter closure,” which represents the “coupling strength” system. Observations from Cabauw, Netherlands, Dome C, Antarctica,...
In the stable boundary layer (SBL) it is observed often that turbulence not continuous in space and time. This discontinuous, intermittent causes alternations from mean evolution of stratified atmospheric layer, which may result an oscillatory type behavior near-surface wind speed temperature. It well known SBL can be generated by various mechanisms. paper focuses on intermittency generating mechanism arises a direct interaction lower atmosphere (first tens meters) with vegetation surface,...
In land surface models, which account for the energy balance at surface, subsurface heat transport is an important component that reciprocally influences ground, sensible, and latent fluxes net radiation. most parameterizations are commonly simplified computational efficiency. A simplification made in all models to disregard sensible of rain, H l , convective flow, q cv i.e., through moisture redistribution. These simplifications act decouple from subsurface, not realistic. The influence on...
The collapse of turbulence in a plane channel flow is studied, as simple analogy stably stratified atmospheric flow. Turbulence parameterized by first-order closure and the surface heat flux prescribed, together with wind speed temperature at model top. To study phenomenon both numerical simulations linear stability analysis are used. nonclassical sense that set equations turbulent analyzed instead particular laminar solution. analytical theory predicts when certain critical value parameter...
The Weather Research and Forecasting Model (WRF) the Regional Atmospheric Mesoscale System (RAMS) are frequently used for (regional) weather, climate air quality studies.This paper covers an evaluation of these models a windy calm episode against Cabauw tower observations (Netherlands), with special focus on representation physical processes in atmospheric boundary layer (ABL).In addition, area averaged sensible heat flux by scintillometry utilized which enables grid scale model fluxes at...
The collapse of turbulence in a pressure‐driven, cooled channel flow is studied by using 3D direct numerical simulations (DNS) combination with theoretical analysis local similarity model. Previous studies DNS reported definite cases when the normalized surface cooling h / L (with depth and Obukhov length) exceeded value 0.5. A recent study present authors succeeded explaining this so‐called maximum sustainable heat flux (MSHF) theory. This states that may occur ambient momentum too weak to...
In the stable boundary layer it is often observed that turbulence not continuous in space and time. This discontinuous, intermittent causes alterations from mean evolution of stratified atmospheric layer, which may result an oscillatory type behavior near-surface wind speed temperature. paper focuses on intermittency generating mechanism arises a direct interaction lower atmosphere (first tens meters) with vegetation surface, without air aloft. atmosphere‐surface (ASI) associated essential...