196 results on '"Vilà‐Guerau de Arellano, J."'
Search Results
2. Increasing complexity in Aerodynamic Gradient flux calculations inside the roughness sublayer applied on a two-year dataset
- Author
-
Melman, E.A., Rutledge-Jonker, S., Braam, M., Frumau, K.F.A., Moene, A.F., Shapkalijevski, M., Vilà-Guerau de Arellano, J., and van Zanten, M.C.
- Published
- 2024
- Full Text
- View/download PDF
3. Unraveling the diurnal atmospheric ammonia budget of a prototypical convective boundary layer
- Author
-
Schulte, R.B., van Zanten, M.C., Rutledge-Jonker, S., Swart, D.P.J., Wichink Kruit, R.J., Krol, M.C., van Pul, W.A.J., and Vilà-Guerau de Arellano, J.
- Published
- 2021
- Full Text
- View/download PDF
4. The Benefits and Challenges of Downscaling a Global Reanalysis With Doubly‐Periodic Large‐Eddy Simulations
- Author
-
van Stratum, B. J. H., primary, van Heerwaarden, C. C., additional, and Vilà‐Guerau de Arellano, J., additional
- Published
- 2023
- Full Text
- View/download PDF
5. Interactions between vegetation, atmospheric turbulence and clouds under a wide range of background wind conditions
- Author
-
Sikma, M., Ouwersloot, H.G., Pedruzo-Bagazgoitia, X., van Heerwaarden, C.C., and Vilà-Guerau de Arellano, J.
- Published
- 2018
- Full Text
- View/download PDF
6. Investigating the Diurnal Radiative, Turbulent, and Biophysical Processes in the Amazonian Canopy‐Atmosphere Interface by Combining LES Simulations and Observations
- Author
-
Pedruzo‐Bagazgoitia, X., primary, Patton, E. G., additional, Moene, A. F., additional, Ouwersloot, H. G., additional, Gerken, T., additional, Machado, L. A. T., additional, Martin, S. T., additional, Sörgel, M., additional, Stoy, P. C., additional, Yamasoe, M. A., additional, and Vilà‐Guerau de Arellano, J., additional
- Published
- 2023
- Full Text
- View/download PDF
7. Numerical simulation of the interaction between ammonium nitrate aerosol and convective boundary-layer dynamics
- Author
-
Barbaro, E., Krol, M.C., and Vilà-Guerau de Arellano, J.
- Published
- 2015
- Full Text
- View/download PDF
8. Comparison of C3 Photosynthetic Responses to Light and CO 2 Predicted by the Leaf Photosynthesis Models of Farquhar et al. (1980) and Goudriaan et al. (1985)
- Author
-
van Diepen, K. H. H., primary, Goudriaan, J., additional, Vilà‐Guerau de Arellano, J., additional, and de Boer, H. J., additional
- Published
- 2022
- Full Text
- View/download PDF
9. Cloud Shading Effects on Characteristic Boundary-Layer Length Scales
- Author
-
Horn, G. L., Ouwersloot, H. G., Vilà-Guerau de Arellano, J., and Sikma, M.
- Published
- 2015
- Full Text
- View/download PDF
10. Comparison of C3 Photosynthetic Responses to Light and CO2 Predicted by the Leaf Photosynthesis Models of Farquhar et al. (1980) and Goudriaan et al. (1985).
- Author
-
van Diepen, K. H. H., Goudriaan, J., Vilà‐Guerau de Arellano, J., and de Boer, H. J.
- Subjects
SCIENTIFIC literature ,PHOTOSYNTHESIS ,STRUCTURAL frame models ,QUANTUM efficiency ,ELECTRON transport - Abstract
The leaf photosynthesis models developed by Farquhar et al. (1980, https://doi.org/10.1007/BF00386231) (FvCB) and Goudriaan et al. (1985, https://doi.org/10.1007/978‐1‐4899‐3665‐3%5f10) (G85) are both used in Earth system and weather models to quantify ecosystem carbon assimilation. Despite their common role, a systematic comparison between these two photosynthesis models is currently lacking in scientific literature. In this technical report we compared the two models in a systematic way. Hereto we performed a comparative analysis of the model structures as well as the modeled responses of photosynthesis to light and CO2 at leaf level. To facilitate future model comparison, we also constructed a lookup table that presents FvCB model parameters fitted to CO2‐response curves from G85 in a wide natural range in photosynthetic capacity at standardized temperature. The structure of the FvCB model differs fundamentally from the G85 model as the FvCB model considers rate‐limiting processes due to Rubisco capacity, electron transport and triose phosphate utilization in parallel, whereas the G85 model considers Rubisco activity and triose phosphate utilization limitation to act in series scaled with quantum use efficiency. The models also differ fundamentally in terms of the parametrization of dark respiration. Still, both models calculate near‐similar responses of photosynthesis to changes in light and CO2 across a wide range in photosynthetic capacity with only two free parameters each. Our work thereby highlights functional similarities between these model approaches despite fundamental differences in model structure. Hence, standardized parameter sets that yield similar photosynthesis responses to light and CO2 may facilitate intercomparison of Earth system and weather models. Plain Language Summary: In Earth system and weather models the exchange of CO2 between the vegetation and the atmosphere is primarily determined by photosynthesis at leaf level. Two commonly applied representations of leaf photosynthesis are based on the models of Farquhar et al. (1980, https://doi.org/10.1007/BF00386231) (FvCB) and Goudriaan et al. (1985, https://doi.org/10.1007/978‐1‐4899‐3665‐3%5f10) (G85). A systematic comparison between the two model approaches is currently lacking in scientific literature. The objective of our technical report is to provide such a comparison and thereby to contribute to an exchange of ideas, data and applications between users of the respective models. We found that the two models calculate a similar response of net photosynthesis to light and CO2, despite having considerable differences in their model structure and representation of physiological processes. The main difference in model structure is that the limitations to photosynthesis in the FvCB model are applied in parallel, whereas in the G85 model they are in series. We also present a lookup table to express parameters from the G85 model in terms of their equivalent FvCB parameters. This technical report thereby contributes to the comparison of models used across the Earth system and weather modeling communities. Key Points: We compare two leaf photosynthesis models, based on different biophysical assumptions, that are both used in Earth system and weather modelingThe two models calculate a near‐similar response of net photosynthesis to light and CO2 despite having considerable differences in their structure and process representation. This finding is significant across a wide range of naturally occurring photosynthetic capacities in vegetationThrough a flowchart, a comparison of photosynthetic response to light and CO2 and a parameter conversion table, we aim to enable more communication and exchange of data between users of the two models within the Earth system and weather modeling communities [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
11. Analytical Solution for the Convectively-Mixed Atmospheric Boundary Layer
- Author
-
Ouwersloot, H. G. and Vilà-Guerau de Arellano, J.
- Published
- 2013
- Full Text
- View/download PDF
12. Impacts of Aerosol Shortwave Radiation Absorption on the Dynamics of an Idealized Convective Atmospheric Boundary Layer
- Author
-
Barbaro, E., Vilà-Guerau de Arellano, J., Krol, M. C., and Holtslag, A. A. M.
- Published
- 2013
- Full Text
- View/download PDF
13. Poster 25 Impact of meteorological factors on turbulent dispersion over complex terrain
- Author
-
Saavedra, S., Souto, J.A., and Vilà-Guerau de Arellano, J.
- Published
- 2007
- Full Text
- View/download PDF
14. The dispersion of chemically reactive species in the atmospheric boundary layer
- Author
-
Vilà-Guerau de Arellano, J., Dosio, A., Vinuesa, J.-F., Holtslag, A. A. M., and Galmarini, S.
- Published
- 2004
- Full Text
- View/download PDF
15. Impacts of topography and land degradation on the sea breeze over eastern Spain
- Author
-
Miao, J.-F., Kroon, L. J. M., Vilà-Guerau de Arellano, J., and Holtslag, A. A. M.
- Published
- 2003
- Full Text
- View/download PDF
16. Interactions Between the Amazonian Rainforest and Cumuli Clouds: A Large‐Eddy Simulation, High‐Resolution ECMWF, and Observational Intercomparison Study
- Author
-
Vilà‐Guerau de Arellano, J., primary, Wang, X., additional, Pedruzo‐Bagazgoitia, X., additional, Sikma, M., additional, Agustí‐Panareda, A., additional, Boussetta, S., additional, Balsamo, G., additional, Machado, L. A. T., additional, Biscaro, T., additional, Gentine, P., additional, Martin, S. T., additional, Fuentes, J. D., additional, and Gerken, T., additional
- Published
- 2020
- Full Text
- View/download PDF
17. Three‐Dimensional Radiative Effects By Shallow Cumulus Clouds on Dynamic Heterogeneities Over a Vegetated Surface
- Author
-
Veerman, M. A., primary, Pedruzo‐Bagazgoitia, X., additional, Jakub, F., additional, Vilà‐Guerau de Arellano, J., additional, and van Heerwaarden, C. C., additional
- Published
- 2020
- Full Text
- View/download PDF
18. Quantifying the Feedback Between Rice Architecture, Physiology, and Microclimate Under Current and Future CO 2 Conditions
- Author
-
Sikma, M., primary, Ikawa, H., additional, Heusinkveld, B. G., additional, Yoshimoto, M., additional, Hasegawa, T., additional, Groot Haar, L. T., additional, Anten, N. P. R., additional, Nakamura, H., additional, Vilà‐Guerau de Arellano, J., additional, Sakai, H., additional, Tokida, T., additional, Usui, Y., additional, and Evers, J. B., additional
- Published
- 2020
- Full Text
- View/download PDF
19. Ozone exchange within and above an irrigated Californian orchard
- Author
-
Brown, J.S., primary, Shapkalijevski, M.M., additional, Krol, M.C., additional, Karl, T., additional, Ouwersloot, H.G., additional, Moene, A.F., additional, Patton, E.G., additional, and Vilà-Guerau De Arellano, J., additional
- Published
- 2020
- Full Text
- View/download PDF
20. Impact of Future Warming and Enhanced [CO 2 ] on the Vegetation‐Cloud Interaction
- Author
-
Sikma, M., primary, Vilà‐Guerau de Arellano, J., additional, Pedruzo‐Bagazgoitia, X., additional, Voskamp, T., additional, Heusinkveld, B.G., additional, Anten, N.P.R., additional, and Evers, J.B., additional
- Published
- 2019
- Full Text
- View/download PDF
21. Assessment report on NRP subtheme “Atmospheric processes & UV-B radiation”
- Author
-
Guicherit, R., primary, ten Brink, H., additional, Ruijgrok, W., additional, Vosbeek, M., additional, Allaart, M., additional, van Dorland, R., additional, Feijt, A.J., additional, Kuik, F., additional, van Lammeren, A.C.A.P., additional, van Meijgaard, E., additional, Stammes, P., additional, Verver, G.H.L., additional, van Duyl, F.C., additional, Lindeboom, H.J., additional, Osinga, R., additional, Beck, J.P., additional, Bordewijk, J., additional, van Pul, W.A.J., additional, Reinen, H., additional, Schlamann, E., additional, Slaper, H., additional, Swart, D.P.J., additional, The, T.H.P., additional, Veenstra, D.L., additional, Dijkhuizen, J., additional, Gieskens, W.W.C., additional, Hansen, T.A., additional, van der Maarel, M.J.E.C., additional, Quest, P., additional, Stefels, J., additional, Bregman, B., additional, Vilà-Guerau de Arellano, J., additional, Baart, A., additional, Bosman, R., additional, Builtjes, P.J.H., additional, Esser, P., additional, Guicherit, R., additional, Kramer, K.J.M., additional, Kwint, R.L.J., additional, and Roemer, M., additional
- Published
- 1995
- Full Text
- View/download PDF
22. Spatio-temporal tomography of the lower troposphere using GPS signals
- Author
-
Flores, A., Rius, A., Vilà-Guerau de Arellano, J., and Escudero, A.
- Published
- 2001
- Full Text
- View/download PDF
23. Integrating canopy and large-scale atmospheric effects in the convective boundary-layer dynamics and chemistry during the CHATS experiment
- Author
-
Shapkalijevski, M., Ouwersloot, Huug, Moene, A.F., and Vilà-Guerau De Arellano, J.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science - Abstract
By characterizing the dynamics of a convective boundary layer above a relatively sparse and uniform orchard canopy, we investigated the impact of the roughness-sublayer (RSL) representation on the predicted diurnal variability of surface fluxes and state variables. Our approach combined numerical experiments, using an atmospheric mixed-layer model including a land-surface-vegetation representation, and measurements from the Canopy Horizontal Array Turbulence Study (CHATS) field experiment near Dixon, California. The RSL is parameterized using an additional factor in the standard Monin–Obukhov similarity theory flux-profile relationships that takes into account the canopy influence on the atmospheric flow. We selected a representative case characterized by southerly wind conditions to ensure well-developed RSL over the orchard canopy. We then investigated the sensitivity of the diurnal variability of the boundary-layer dynamics to the changes in the RSL key scales, the canopy adjustment length scale, Lc, and the β = u*/|U| ratio at the top of the canopy due to their stability and dependence on canopy structure. We found that the inclusion of the RSL parameterization resulted in improved prediction of the diurnal evolution of the near-surface mean quantities (e.g. up to 50 % for the wind velocity) and transfer (drag) coefficients. We found relatively insignificant effects on the modelled surface fluxes (e.g. up to 5 % for the friction velocity, while 3 % for the sensible and latent heat), which is due to the compensating effect between the mean gradients and the drag coefficients, both of which are largely affected by the RSL parameterization. When varying Lc (from 10 to 20 m) and β (from 0.25 to 0.4 m), based on observational evidence, the predicted friction velocity is found to vary by up to 25 % and the modelled surface-energy fluxes (sensible heat, SH, and latent heat of evaporation, LE) vary up to 2 and 9 %. Consequently, the boundary-layer height varies up to 6 %. Furthermore, our analysis indicated that to interpret the CHATS measurements above the canopy, the contributions of non-local effects such as entrainment, subsidence and the advection of heat and moisture over the CHATS site need to be taken into account.
- Published
- 2017
24. Quantifying the Feedback Between Rice Architecture, Physiology, and Microclimate Under Current and Future CO2 Conditions.
- Author
-
Sikma, M., Ikawa, H., Heusinkveld, B. G., Yoshimoto, M., Hasegawa, T., Groot Haar, L. T., Anten, N. P. R., Nakamura, H., Vilà‐Guerau de Arellano, J., Sakai, H., Tokida, T., Usui, Y., and Evers, J. B.
- Subjects
RICE varieties ,CLIMATE change ,ATMOSPHERIC carbon dioxide ,PLANT physiology ,RICE - Abstract
The article presents a study which examined the relationships between rice architecture, physiology, and microclimate under present and future microenvironments as of March 2020 to determine the micrometeorological effects of rice variety choices in atmospheric carbon dioxide (CO
2 ) and climate change. It discusses the use of the rice varieties Takanari and Koshihikari to determine the relation between plant physiology and microclimate.- Published
- 2020
- Full Text
- View/download PDF
25. Impact of Future Warming and Enhanced [CO2] on the Vegetation‐Cloud Interaction.
- Author
-
Sikma, M., Vilà‐Guerau de Arellano, J., Pedruzo‐Bagazgoitia, X., Voskamp, T., Heusinkveld, B.G., Anten, N.P.R., and Evers, J.B.
- Subjects
PHYSIOLOGICAL effects of carbon dioxide ,PLANT transpiration ,KINETIC energy ,GLOBAL warming ,PLANT physiology - Abstract
The effects of increases in carbon dioxide and temperature on the vegetation‐atmosphere‐cloud interaction are studied with a bottom‐up approach. Using the 3‐D large‐eddy simulation technique coupled with a CO2‐sensitive dynamic plant physiological submodel, we aimed to spatially and temporally understand the surface and vegetation forcing on the coupled land‐atmosphere interactions in future scenarios. Four simulations were designed: a control simulation for current conditions, an enhanced carbon dioxide simulation (current +200 ppm), an elevated temperature simulation (current +2 K), and a simulation covering the combination of both elevations in temperature and CO2. With elevations in carbon dioxide, plant transpiration is reduced due to stomatal closure, resulting in reduced latent‐ and increased sensible heat fluxes. Although no effects on cloud cover were found in this simulation, the in‐cloud moisture flux was enhanced. Elevations in temperature yielded opposite results with reduced sensible and increased latent heat fluxes, which reduced the turbulent kinetic energy and buoyancy rates, thereby negatively impacting cloud formation. Our future climate mimicking simulation shows minimal changes in the regional energy balance due to offsetting effects between increased temperature and [CO2], while plant photosynthesis increased and transpiration decreased. The atmospheric boundary layer was drier, even though surface fluxes were very similar current conditions, thereby hampering cloud formation and development. Our results highlight the necessity of small scales and interactions, which require a bottom‐up approach to be able to accurately capture the nonlinear plant‐atmosphere interactions. Key Points: Ignoring subgrid‐scale processes can lead to serious misrepresentation of plant‐atmosphere interactions that drive the future atmosphereElevations in temperature and CO2 nonlinearly affect plant physiology that drive the surface energy balance and atmospheric stateIn future atmospheres, we find strong reductions in boundary layer cloud cover and moisture transport [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
26. Grain Yield Observations Constrain Cropland CO2 Fluxes Over Europe
- Author
-
Combe, M., primary, de Wit, A. J. W., additional, Vilà-Guerau de Arellano, J., additional, van der Molen, M. K., additional, Magliulo, V., additional, and Peters, W., additional
- Published
- 2017
- Full Text
- View/download PDF
27. Direct and Diffuse Radiation in the Shallow Cumulus–Vegetation System: Enhanced and Decreased Evapotranspiration Regimes
- Author
-
Pedruzo-Bagazgoitia, X., primary, Ouwersloot, H. G., additional, Sikma, M., additional, van Heerwaarden, C. C., additional, Jacobs, C. M. J., additional, and Vilà-Guerau de Arellano, J., additional
- Published
- 2017
- Full Text
- View/download PDF
28. Understanding the impact of plant competition on the coupling between vegetation and the atmosphere
- Author
-
van Loon, M.P., Dekker, S.C., Anten, N.P.R., Rietkerk, M., Vilà-Guerau De Arellano, J., Sub Ecology and Biodiversity, Environmental Sciences, and Spatial Ecology and Global Change
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,plant competition ,Meteorology and Air Quality ,Leaf Area Index ,Centre for Crop Systems Analysis ,modeling ,optimality principle ,PE&RC ,atmosphere-vegetation feedbacks ,PHOTOSYNTHETIC CARBON GAIN ,LEAF-AREA INDEX ,ELEVATED CO2 ,STOMATAL CONDUCTANCE ,EDDY COVARIANCE ,TRACTABLE MODEL ,NITROGEN ,LIGHT ,TRANSPIRATION ,OPTIMIZATION [KeyWords Plus] - Abstract
Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation functioning and associated atmospheric interactions. Our aim was to investigate how the coupling between vegetation and atmosphere is influenced by plant competition. Though included in some coupled vegetation-atmosphere models, little attention has been paid to systematically study the impact of plant competition in determining the evolution of surface and atmospheric variables. We used a coupled vegetation-atmosphere model and included a new representation of plant competition. We compared the model results with diurnal data from Ameriflux Bondville site over a growing season. Including competition improved LAI (Leaf Area Index) and net ecosystem exchange of CO2 (NEE) predictions; if competition was not considered, there were strong deviations from observations. Remarkably, competition increased LAI while it reduced whole stand photosynthesis, resulting in a less negative NEE. Finally, independent of competition, latent heat flux, surface temperature, specific humidity, and atmospheric CO2 are well reproduced by the model. Only the sensible heat flux was overestimated, mainly due to the imbalance in the surface energy balance that can lead to lower measured sensible heat fluxes. Sensitivity analysis showed that the importance of plant competition on model outcomes increases with more nitrogen and water availability and may differ between soil types. We thus quantified the potential effect of plant competition in a coupled vegetation-atmosphere system and showed that it strongly influences this system, and therefore, we propose that competition should be considered in more vegetation-atmosphere models.
- Published
- 2015
29. Cumulative ozone effect on canopy stomatal resistance and the impact on boundary layer dynamics and CO2 assimilation at the diurnal scale: A case study for grassland in the Netherlands
- Author
-
Super, I., Vilà-Guerau De Arellano, J., and Krol, M.C.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,drought ,sensitivity ,yield ,l ,exposure ,vegetation ,atmosphere ,climate-change ,soil-moisture ,conductance - Abstract
Biological, chemical, and dynamical processes occurring at the surface strongly interact at diurnal scales. Therefore, this study examines the seasonal ozone impact on stomatal resistance, surface energy balance, boundary layer dynamics, and CO2 assimilation at this (sub)diurnal scale under changing conditions. We combine a seasonal canopy resistance module with a surface-boundary layer model that solves the diurnal evolution of dynamical and chemical variables in a well-mixed, convective boundary layer. The model is constrained with observations from Cabauw (Netherlands) for the dry year 2003, representing a well-mixed boundary layer at midlatitudes over water-stressed grassland. To quantify the ozone impact, the Cumulative Uptake of Ozone is calculated over a growing season, which gives an estimate of the reduction in stomatal aperture and photosynthesis. From a sensitivity analysis with mixed-layer temperature and soil moisture content we conclude that drought is the dominant factor that determines the surface energy partitioning and limits CO2 assimilation. Although drought causes stomatal closure, the results indicate that ozone damage, nevertheless, occurs. A second sensitivity analysis with CO2 and ozone shows that ozone damage causes an increase in stomatal resistance of up to 40% under high ozone levels and that CO2-induced stomatal closure limits ozone damage. The impact on boundary layer development through the effect of CO2 and ozone on the stomatal resistance is much smaller. At the diurnal scale soil moisture influences the surface energy partitioning, which affects the entrainment of ozone-rich air. Due to ozone damage, the CO2 assimilation flux is reduced by about 15%.
- Published
- 2015
30. Impact of Future Warming and Enhanced [CO2] on the Vegetation‐Cloud Interaction
- Author
-
Sikma, M., Vilà‐Guerau de Arellano, J., Pedruzo‐Bagazgoitia, X., Voskamp, T., Heusinkveld, B.G., Anten, N.P.R., and Evers, J.B.
- Abstract
The effects of increases in carbon dioxide and temperature on the vegetation‐atmosphere‐cloud interaction are studied with a bottom‐up approach. Using the 3‐D large‐eddy simulation technique coupled with a CO2‐sensitive dynamic plant physiological submodel, we aimed to spatially and temporally understand the surface and vegetation forcing on the coupled land‐atmosphere interactions in future scenarios. Four simulations were designed: a control simulation for current conditions, an enhanced carbon dioxide simulation (current +200 ppm), an elevated temperature simulation (current +2 K), and a simulation covering the combination of both elevations in temperature and CO2. With elevations in carbon dioxide, plant transpiration is reduced due to stomatal closure, resulting in reduced latent‐ and increased sensible heat fluxes. Although no effects on cloud cover were found in this simulation, the in‐cloud moisture flux was enhanced. Elevations in temperature yielded opposite results with reduced sensible and increased latent heat fluxes, which reduced the turbulent kinetic energy and buoyancy rates, thereby negatively impacting cloud formation. Our future climate mimicking simulation shows minimal changes in the regional energy balance due to offsetting effects between increased temperature and [CO2], while plant photosynthesis increased and transpiration decreased. The atmospheric boundary layer was drier, even though surface fluxes were very similar current conditions, thereby hampering cloud formation and development. Our results highlight the necessity of small scales and interactions, which require a bottom‐up approach to be able to accurately capture the nonlinear plant‐atmosphere interactions. Ignoring subgrid‐scale processes can lead to serious misrepresentation of plant‐atmosphere interactions that drive the future atmosphereElevations in temperature and CO2nonlinearly affect plant physiology that drive the surface energy balance and atmospheric stateIn future atmospheres, we find strong reductions in boundary layer cloud cover and moisture transport
- Published
- 2019
- Full Text
- View/download PDF
31. Influence of Canopy Seasonal Changes on Turbulence Parameterization within the Roughness Sublayer over an Orchard Canopy
- Author
-
Shapkalijevski, M., primary, Moene, A. F., additional, Ouwersloot, H. G., additional, Patton, E. G., additional, and Vilà-Guerau de Arellano, J., additional
- Published
- 2016
- Full Text
- View/download PDF
32. Supplementary material to "Understanding isoprene photo-oxidation using observations and modelling over a subtropical forest in the Southeast US"
- Author
-
Su, L., primary, Patton, E. G., additional, Vilà-Guerau de Arellano, J., additional, Guenther, A. B., additional, Kaser, L., additional, Yuan, B., additional, Xiong, F., additional, Shepson, P. B., additional, Zhang, L., additional, Miller, D. O., additional, Brune, W. H., additional, Baumann, K., additional, Edgerton, E., additional, Weinheimer, A., additional, and Mak, J. E., additional
- Published
- 2015
- Full Text
- View/download PDF
33. Understanding isoprene photo-oxidation using observations and modelling over a subtropical forest in the Southeast US
- Author
-
Su, L., primary, Patton, E. G., additional, Vilà-Guerau de Arellano, J., additional, Guenther, A. B., additional, Kaser, L., additional, Yuan, B., additional, Xiong, F., additional, Shepson, P. B., additional, Zhang, L., additional, Miller, D. O., additional, Brune, W. H., additional, Baumann, K., additional, Edgerton, E., additional, Weinheimer, A., additional, and Mak, J. E., additional
- Published
- 2015
- Full Text
- View/download PDF
34. Turbulence vertical structure of the boundary layer during the afternoon transition
- Author
-
Darbieu, C., primary, Lohou, F., additional, Lothon, M., additional, Vilà-Guerau de Arellano, J., additional, Couvreux, F., additional, Durand, P., additional, Pino, D., additional, Patton, E. G., additional, Nilsson, E., additional, Blay-Carreras, E., additional, and Gioli, B., additional
- Published
- 2015
- Full Text
- View/download PDF
35. Aerosolen in de convectieve grenslaag: stralingseffecten op het gekoppelde land-atmosfeer systeem
- Author
-
Wilde Barbaro, E., Vilà-Guerau de Arellano, J., Schröter, J.S., Donovan, D., and Krol, M.C.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality - Published
- 2013
36. Influence of boundary layer dynamics and isoprene chemistry on the organic aerosol budget in a tropical forest
- Author
-
Janssen, R.H.H., Vilà-Guerau de Arellano, J., Jimenez, J.L., Ganzeveld, L.N., Robinson, N.H., Allan, J.D., Coe, H., and Pugh, T.A.M.
- Subjects
Meteorologie en Luchtkwaliteit ,atmospheric chemistry ,rain-forest ,WIMEK ,Meteorology and Air Quality ,campaign ,oxidation ,photooxidation ,Earth System Science ,inversion ,impact ,Leerstoelgroep Aardsysteemkunde ,surface ,op3 project ,soa formation - Abstract
We study the organic aerosol (OA) budget in a tropical forest by analyzing a case that is representative for the OP3 campaign at Borneo. A model is designed that combines the essential dynamical and chemical processes that drive the diurnal evolution of reactants in the atmospheric boundary layer (BL). In this way, the model simultaneously represents the effects and interactions of various dynamical and chemical factors on the OA budget. The model is able to reproduce the observed diurnal dynamics of the BL, including the evolution of most chemical species involved in secondary organic aerosol (SOA) formation. A budget analysis of the contributions of the dynamic and chemical processes reveals the significance of the entrainment process in the diurnal evolution of SOA. Further, we perform a series of sensitivity analyses to determine the effect of meteorological forcings and isoprene chemical pathways on the OA budget. Subsidence and advection of cool air have opposing effects on the OA concentration, although both suppress BL growth. Recycling of the OH radical in the oxidation of isoprene may affect the amount of SOA that is formed, but must be understood better before its impact can be definitely determined. SOA formation from isoprene is calculated for both the low- and high-NOx pathway, with the latter dominating the isoprene peroxy radical chemistry. Finally, we study the significance of SOA formation through the reactive uptake of isoprene epoxydiols on acidic sulfate aerosol. Despite the incorporation of these new pathways, the OA concentration is systematically underestimated by about a factor of 2.
- Published
- 2013
37. Quantifying the uncertainties of advection and boundary layer dynamics on the diurnal carbon dioxide budget
- Author
-
Pino, D., Kaikkonen, J.P., and Vilà-Guerau de Arellano, J.
- Subjects
Meteorologie en Luchtkwaliteit ,atmospheric co2 ,WIMEK ,Meteorology and Air Quality ,entrainment ,exchange ,cabauw tower ,transport models ,regional-scale ,flux ,co2 mixing ratios ,Astrophysics::Earth and Planetary Astrophysics ,error characterization ,tall tower ,Physics::Atmospheric and Oceanic Physics - Abstract
[1] We investigate the uncertainties in the carbon dioxide (CO2) mixing ratio and inferred surface flux associated with boundary layer processes and advection by using mixed-layer theory. By extending the previous analysis presented by Pino et al. (2012), new analytical expressions are derived to quantify the uncertainty of CO2 mixing ratio or surface flux associated to, among others, boundary layer depth, early morning CO2 mixing ratio at the mixed layer or at the free atmosphere; or CO2 advection. We identify and calculate two sorts of uncertainties associated to the CO2 mixing ratio and surface flux: instantaneous and past (due to advection). The numerical experiments are guided and constrained by meteorological and CO2 observations taken at the Cabauw 213 m tower. We select 2 days (25 September 2003 and 12 March 2004) with a well-defined convective boundary layer but different CO2 advection contributions. Our sensitivity analysis shows that uncertainty of the CO2 advection in the boundary layer due to instantaneous uncertainties represents at 1600 LT on 12 March 2004 a contribution of 2¿ppm and 0.072 mg m-2s-1 in the uncertainty of the CO2 mixing ratio and inferred surface flux, respectively. Taking into account that the monthly averaged minimum CO2 surface flux for March 2004 was -0.55 mg m-2s-1, the error on the surface flux is on the order of 10%. By including CO2 advection in the analytical expressions, we demonstrate that the uncertainty of the CO2 mixing ratio or surface flux also depends on the past uncertainties of the boundary layer depth.
- Published
- 2013
38. Quantifying the transport of subcloud layer reactants by shallow cimulus clouds over the Amazon
- Author
-
Ouwersloot, H.G., Vilà-Guerau De Arellano, J., van Stratum, B.J.H., Krol, M.C., and Lelieveld, J.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,model ,Meteorology and Air Quality ,campaign ,topped mixed layers ,chemistry ,fluxes ,land ,diurnal cycle ,large-eddy simulation ,convective boundary-layer ,surface ,Physics::Chemical Physics ,Physics::Atmospheric and Oceanic Physics - Abstract
We investigate the vertical transport of atmospheric chemical reactants from the subcloud layer to the cumulus cloud layer driven by shallow convection over the Amazon during the dry season. The dynamical and chemical assumptions needed for mesoscale and global chemistry transport model parametrizations are systematically analyzed using a Large Eddy Simulation model. We quantify the mass flux transport contribution to the temporal evolution of reactants. Isoprene, a key atmospheric compound over the tropical rain forest, decreases by 8.5% h-1 on average and 15% h-1 at maximum due to mass¿flux¿induced removal. We apply mass flux parametrizations for the transport of chemical reactants and obtain satisfactory agreement with numerically resolved transport, except for some reactants like O3, NO, and NO2. The latter is caused by the local partitioning of reactants, influenced by UV radiation extinction by clouds and small¿scale variability of ambient atmospheric compounds. By considering the longer¿lived NOx (NO + NO2), the transport is well represented by the parametrization. Finally, by considering heterogeneous surface exchange conditions, it is demonstrated that the parametrizations are sensitive to boundary conditions due to changes in the boundary layer dynamics.
- Published
- 2013
39. An evaluation of WRF's ability to reproduce the surface wind over complex terrain based on typical circulation patterns
- Author
-
Jiménez, P. A., Dudhia, J., González Rouco, J. Fidel, Montávez, J. P., García Bustamante, E., Navarro, J., Vilà-Guerau de Arellano, J., and Múñoz Roldán, A.
- Subjects
validation ,Meteorologie en Luchtkwaliteit ,Astrofísica ,WIMEK ,mesoscale model ,Meteorology and Air Quality ,variability ,regional climate model ,united-states ,WRF ,reanalysis ,simulation ,Astronomía ,quality-assurance ,classification ,cluster-analysis ,Multiyear evaluation ,Wind patterns ,Surface wind ,Complex terrain - Abstract
The performance of the Weather Research and Forecasting (WRF) model to reproduce the surface wind circulations over complex terrain is examined. The atmospheric evolution is simulated using two versions of the WRF model during an over 13¿year period (1992 to 2005) over a complex terrain region located in the northeast of the Iberian Peninsula. A high horizontal resolution of 2km is used to provide an accurate representation of the terrain features. The multiyear evaluation focuses on the analysis of the accuracy displayed by the WRF simulations to reproduce the wind field of the six typical wind patterns (WPs) identified over the area in a previous observational work. Each pattern contains a high number of days which allows one to reach solid conclusions regarding the model performance. The accuracy of the simulations to reproduce the wind field under representative synoptic situations, or pressure patterns (PPs), of the Iberian Peninsula is also inspected in order to diagnose errors as a function of the large-scale situation. The evaluation is accomplished using daily averages in order to inspect the ability of WRF to reproduce the surface flow as a result of the interaction between the synoptic scale and the regional topography. Results indicate that model errors can originate from problems in the initial and lateral boundary conditions, misrepresentations at the synoptic scale, or the realism of the topographic features.
- Published
- 2013
40. A large-eddy simulation of the phase transition of ammonium nitrate in a convective boundary layer
- Author
-
Aan de Brugh, J. M. J., Ouwersloot, H. G., Vilà-Guerau de Arellano, J., and Krol, M. C.
- Subjects
Meteorologie en Luchtkwaliteit ,gas-particle interactions ,WIMEK ,Meteorology and Air Quality ,inorganic aerosol ,relative-humidity ,dutch heathland ,exchange fluxes ,thermodynamic-equilibrium model ,heterogeneous land surfaces ,forest ,Physics::Space Physics ,Physics::Atmospheric and Oceanic Physics ,turbulent-diffusion ,chemical-reactions - Abstract
Under warm and dry conditions, ammonium nitrate aerosol outgasses to form ammonia and nitric acid in the lower atmospheric boundary layer. In the upper boundary layer, where the temperature is lower and the relative humidity is higher, nitric acid and ammonia condense back to the aerosol phase. Measurements show that aerosol nitrate mixing ratios increase with altitude, confirming this phase transition. Since phase equilibrium is not reached instantaneously, updrafts transport aerosol-poor air from the surface to high altitudes and aerosol-rich air subsides from high altitudes to the surface under turbulent conditions. As a result, the partitioning deviates from equilibrium, so the horizontal and temporal variabilities of the aerosol nitrate mixing ratio are enhanced and a continuous downward aerosol nitrate flux emerges. We postulate that observations of this variability and flux should not be interpreted as instrument noise and deposition of nitrate. In an idealized large-eddy simulation (LES) experiment of a convective boundary layer, we find that the larger variability and flux occurred at about one third of the boundary layer height. Both are largest when the gas-aerosol partitioning time scale is assumed to be about half the time scale of turbulence. Our LES result shows negatively skewed nitrate mixing ratios. Under colder conditions, a smaller fraction of ammonium nitrate aerosol outgasses at the surface, so the absolute effect of nitrate repartitioning becomes smaller. However, dimensionless statistical properties do not change as long as the turbulent properties of the boundary layer remain similar. This indicates that the identified processes are also present under colder conditions.
- Published
- 2013
41. Grain Yield Observations Constrain Cropland CO2 Fluxes Over Europe.
- Author
-
Combe, M., de Wit, A. J. W., Vilà‐Guerau de Arellano, J., van der Molen, M. K., Magliulo, V., and Peters, W.
- Abstract
Abstract: Carbon exchange over croplands plays an important role in the European carbon cycle over daily to seasonal time scales. A better description of this exchange in terrestrial biosphere models—most of which currently treat crops as unmanaged grasslands—is needed to improve atmospheric CO
2 simulations. In the framework we present here, we model gross European cropland CO2 fluxes with a crop growth model constrained by grain yield observations. Our approach follows a two‐step procedure. In the first step, we calculate day‐to‐day crop carbon fluxes and pools with the WOrld FOod STudies (WOFOST) model. A scaling factor of crop growth is optimized regionally by minimizing the final grain carbon pool difference to crop yield observations from the Statistical Office of the European Union. In a second step, we re‐run our WOFOST model for the full European 25 × 25 km gridded domain using the optimized scaling factors. We combine our optimized crop CO2 fluxes with a simple soil respiration model to obtain the net cropland CO2 exchange. We assess our model's ability to represent cropland CO2 exchange using 40 years of observations at seven European FluxNet sites and compare it with carbon fluxes produced by a typical terrestrial biosphere model. We conclude that our new model framework provides a more realistic and strongly observation‐driven estimate of carbon exchange over European croplands. Its products will be made available to the scientific community through the ICOS Carbon Portal and serve as a new cropland component in the CarbonTracker Europe inverse model. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
42. On the role of large-scale forcings on the development of the atmospheric boundary layer during the BLLAST field campaign
- Author
-
Pietersen, H.P., Vilà-Guerau de Arellano, J., de Coster, O., van de Boer, A., Hartogensis, O.K., Pino, D., Gioli, B., Durand, P., Lothon, M., Lohou, F., Reuder, J., Jonassen, M., and Faloona, I.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science ,Hydrology and Quantitative Water Management ,Hydrologie en Kwantitatief Waterbeheer - Abstract
Guided and constrained by a complete data set of surface and upper-air observations taken during the fifth Intensive Observational Period (IOP-05, 25th June 2011) of the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) experiment, we reconstruct the evolution of the atmospheric boundary layer (ABL) using mixed-layer theory. The model results are corroborated by UHF radar and multiple profiles done by unmanned and manned aircraft platforms as well as by radiosondes. During the first morning hours, the ABL is mainly controlled by surface forcing, reaching a depth between 500 and 600 meter. At these levels, large-scale subsidence motions become similar in magnitude to the entrainment velocity and the ABL-growth becomes nearly zero. This equilibrium is maintained until the afternoon transition where mixed-layer model results and observations show a decrease of the boundary layer depth in spite of well mixed observed vertical profiles of heat and moisture. We discuss potential explanations to the development of subsidence motions associated to mesoscale flows driven by the proximity of the Pyrenees mountain range and to large-scale forcing. The heat and moisture budgets are also further analyzed with the mixed layer model. We find strong indications of the active role of heat and moisture advection required to reproduce the observed diurnal variability in temperature and specific humidity. By quantifying the budget terms, we are able to obtain a first estimation of the contribution of advection to the heat and moisture budgets. To complete the analysis, we extend the study to examine the turbulent characteristics of the ABL by using aircraft measurements combined with large-eddy simulations. In so doing, we are able to study the role of wind (directional) shear in the development and maintenance of the ABL. IOP05 was characterized by easterly flows within the ABL and westerly winds aloft. Our findings stress the important role of large scale forcing in understanding the ABL development at various stages during BLLAST. The proposed method can also be very useful to support the further interpretation of observations and mesoscale model experiments.
- Published
- 2012
43. Increasing CO2 suppresses boundary-layer clouds in temperate climates
- Author
-
Vilà-Guerau de Arellano, J., van Heerwaarden, C.C., and Lelieveld, J.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science - Abstract
Cumulus clouds in the atmospheric boundary layer play a key role in the hydrologic cycle, in the onset of severe weather by thunderstorms, and in modulating the Earth's reflectivity and climate. How these clouds respond to climate change, in particular over land, and how they interact with the carbon cycle is poorly understood. It is expected that as atmospheric CO2 concentrations rise, the effectiveness of photosynthesis by vegetation will increase. Since this is associated with reduced evapotranspiration, the sensible heat flux increases, which contributes to the surface temperature rise. Using a soil-water-atmosphere-plant model we show that increasing CO2 causes a reduction of boundary layer cloud formation in middle latitudes. This could be partly counteracted by a growth in biomass and greater ability of a warmer atmosphere to take up water. Model results are evaluated with a comprehensive observational data set taken at Cabauw (The Netherlands). We find that current climate conditions are optimal for boundary layer cloud formation over land, while in projections of future conditions, cloudiness will be increasingly suppressed. Our results emphasize the intricate connection between biological and physical aspects of the climate system.
- Published
- 2012
44. Impact of aerosol heat radiation absorption on the dynamics of an atmospheric boundary layer in equilibrium
- Author
-
Barbaro, E.W., Vilà-Guerau de Arellano, J., Krol, M.C., and Holtslag, A.A.M.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science - Abstract
The objective of this work is to investigate the influence of the shortwave radiation (SW) absorption by aerosols on the dynamics and heat budget of the atmospheric boundary layer (ABL). This study is relevant for areas characterized by large concentrations of light-absorbing aerosol, which are known to warm up the ABL 2-10 K/day depending on the amount and vertical distribution of the aerosols. We investigate if aerosols, by warming the ABL and the entrainment zone, contribute to a destabilization of the thermal inversion layer, either by reducing the capping inversion or by stabilizing the lower part of the entrainment zone. The impact of the reduced amount of radiation reaching the surface due to aerosols SW absorption is taken into account. As such numerical experiments are carried out by using a large-eddy simulation (LES) model (DALES code) to study the ABL vertical structure and its time evolution. Mixed-layer theory (0-order bulk model - MXL) is also employed to support DALES results. A radiative transfer code (TUV) is used to calculate the impact of the aerosols absorption on the SW radiation field. The numerical simulations are made for a reference case of a dry, non-polluted free convective ABL in equilibrium, i.e. the boundary layer height is in steady-state. In addition, three other simulations are designed: average (AC), high and extreme aerosol concentrations. They differ from the reference case only by the increasing aerosol concentration (homogeneously distributed) within the ABL. An extra simulation (called TOP) is performed with the AC concentration placed only at the ABL top to investigate if the vertical distribution of aerosols plays a role in changing the entrainment zone dynamics. The simulations are integrated towards a new steady state. The DALES results indicate a shallower ABL for all simulations, compared to the reference case. The ABL-depth decreasing is even more pronounced for the TOP case. Different processes explain this decrease. At the surface, the reduction of SW, due to the aerosols absorption, leads to decrease the surface sensible heat flux (SH), and in consequence it yields to a shallower ABL. In turn, the aerosols absorption also weakens the capping inversion in all the experiments because of the aerosol heat absorption. The absorption also drives an increased stabilization of the upper region of the ABL. Stabilization and the reduced SH together suppress the weakening of the inversion layer, reducing the ABL height. Turbulence characteristics are further analyzed: first, the entrainment velocity increases when the aerosols are located at the top of ABL. The entrainment flux depth changes when aerosols are added, however its magnitude remains the same as for the control case, around 16%. Second, the stabilization below the ABL top leads to a reduction of the temperature variance.
- Published
- 2012
45. Role of residual layer and large-scale phenomena on the evolution of the boundary layer
- Author
-
Blay, E., Pino, D., Vilà-Guerau de Arellano, J., van de Boer, A., de Coster, O., Faloona, I., Garrouste, O., and Hartogensis, O.K.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science ,Physics::Atmospheric and Oceanic Physics - Abstract
Mixed-layer theory and large-eddy simulations are used to analyze the dynamics of the boundary layer on two intensive operational periods during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) campaign: 1st and 2nd of July 2011, when convective boundary layers (CBLs) were observed. Continuous measurements made by several remote sensing and in situ instruments in combination with radiosoundings, and measurements done by unmanned aerial vehicles and an aircraft probed the vertical structure and the temporal evolution of the boundary layer. Mixed layer theory (Tennekes and Driedonks, 1981) and the Dutch Atmospheric Large-Eddy Simulation model (DALES, Heus et al., 2011) are set to reproduce and analyze the dynamics of the atmosphere during these two days. The initial vertical profiles of potential temperature, specific humidity and wind, and the temporal evolution of the surface heat and moisture fluxes prescribed in the model runs are inspired by the observations taken at the two supersites that concentrated most of the instrumentation during the campaign. For DALES the initial profile (at 7 UTC on 1st July and 5 UTC on 2nd July) takes into account the existence of a residual layer above the nocturnal stable layer observed during the early morning. The mixed layer model is initialized when a well-developed convective boundary layer was observed, from 10 UTC. Due to the surface heterogeneity of the area, the models were run separately to analyze the boundary layer conditions at the two different supersites. First, the research focuses on the role-played by the residual layer (RL) on the evolution of the boundary layer. By using DALES, we show the importance of the dynamics of the boundary layer during the previous night to the development of the boundary layer at the morning. DALES, which takes into account the residual layer, is capable to model the observed sudden increase of the boundary layer depth and of the potential temperature occurred during the morning transition. There are different sources, which can be the responsible of the overshooting for instance surface and entrainment fluxes or large-scale phenomena. Analyzing the entrainment buoyancy heat flux, a large increase is obtained by the simulation when the residual layer is incorporated in the mixed layer by the growing convective boundary layer. Consequently, a precise definition of the characteristics of the residual layer is fundamental even though it is complex because the evolution of the main variables in the residual layer during the previous night depends on different factors such as radiation divergence or advection. Once the boundary layer is fully developed around midday, both models are used to study the dynamics of the boundary layer during the studied days. The models are able to reproduce the evolution of the boundary layer depth, potential temperature and specific humidity from late morning. They are also used to analyze the role played by subsidence and large-scale advection during the afternoon transition. During 1st of July, heat and moisture advection are negligible contributions to the heat or moisture budget, respectively, but subsidence plays an important role in the turbulence decay during the afternoon when a clear decrease of boundary layer depth was observed. On 2nd of July the main boundary layer variables follow similar evolution to the previous day, but with a lower maximum of the boundary layer depth. However, in the last part of the day, a front was approaching advecting moisture over the area and increasing the cloud cover. To summarize, the residual layer and large-scale phenomena play a crucial role in the development of the boundary layer during some days of the BLLAST campaign.
- Published
- 2012
46. Understanding and representing the effect of wind shear on the turbulent transfer in the convective boundary layer
- Author
-
Ronda, R.J., Vilà-Guerau de Arellano, J., and Pino, D.
- Subjects
Physics::Fluid Dynamics ,Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science ,Physics::Atmospheric and Oceanic Physics - Abstract
Goal of this study is to quantify the effect of wind shear on the turbulent transport in the dry Convective Boundary Layer (CBL). Questions addressed include the effect of wind shear on the depth of the mixed layer, the effect of wind shear on the depth and structure of the capping inversion, and the effect of wind shear on the entrainment of free tropospheric air into the mixed layer. Following previous research, we use numerical experiments performed with the DALES LES-model varying both the strength and vertical profile of the geostrophic wind. In contrast to previous investigations, the effect of wind shear is analysed using a General Structure Model (GSM), instead of a more traditional zero-order or first order approach. We have selected the GSM framework because it allows for a more detailed assessment of the vertical structure of the capping inversion. Concepts derived within this framework can therefore be more easily transfered to global and meso-scale models turbulent transport parameterizations, as especially in conditions with high wind shear the capping inversion is often of such thickness that it can comprises multiple model layers in state-of-the art meso-scale and Numerical Weather Prediction (NWP) models. The effect of wind shear on the parameterized turbulence transport in NWP and meso-scale models is examined using the Eddy Diffusivity Mass-Flux (EDMF) approach. In contrast with traditional approaches based on K-theory, the EDMF framework acknowledges that turbulent transfer in the CBL can be decomposed into transport due to vertical advection by confined updrafts and diffusive transport (K-theory) within the updrafts and the environmental air. The DALES LES-model results are used to evaluate the effect of wind shear on the different parameters of the EDMF approach. Parameters include the release height and the excess temperature of a parcel that is employed to monitor the updrafts, the vertical velocity of an updraft parcel as it rises through the CBL and penetrates into the capping inversion, and the fraction of air occupied by the updrafts. This study thus extends previous research showing the performance of the EDMF approach in representing turbulent transfer in both clear and cloud-topped boundary layers without wind shear.
- Published
- 2012
47. The Boundary Layer Late Afternoon and Sunset Turbulence 2011 field experiment
- Author
-
Lothon, M., Lohou, F., Durand, P., Couvreux, F., Hartogensis, O.K., Legain, D., Pardyjak, E., Pino, D., Vilà-Guerau de Arellano, J., van de Boer, A., Moene, A.F., and Steeneveld, G.J.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science - Abstract
BLLAST (Boundary Layer Late Afternoon and Sunset Turbulence) aims at better understanding the thermodynamical processes that occur during the late afternoon in the lower troposphere. In direct contact with the Earth surface, the atmospheric boundary layer is governed by buoyant and mechanical turbulence, with a strong diurnal cycle. The late afternoon transition, from the daytime dry convection to the night-time stable boundary layer, still raises a lot of issues and is poorly represented in the meteorological models. Yet, it plays an important role in the transport and diffusion of trace gases, like water vapour, carbon dioxide, pollutants, dusts... How does the afternoon decay in the lower troposphere happen, when the surface sensible heat flux start to sharply decrease ? How do the scales of the motions and transfers change ? What is the impact on the chemical closure and transport of trace gases and aerosols ? How to properly represent those processes in the meteorological models ? An international group is working on those issues by use of observations and numerical simulations, in order to improve our understanding and representation of the turbulent processes of the boundary-layer late afternoon transition. The roles of surface heterogeneity, entrainment at the boundary layer top, large scale subsidence, radiative effects, advection and gravity waves are studied. Due to the large lack of observations during this phase, a field campaign was organized in the vicinity of a 60-m instrumented tower of Laboratoire d'Aérologie, near the Pyrenees ridge in Southwest France, from 14 June to 8 July 2011. This experiment puts together complementary observation resources, in order to obtain an exhaustive description of the boundary-layer dynamical processes, its vertical structure, and the spatial variability related to surface heterogeneity. Continuous measurements (UHF radar and sodar wind profilers, lidars, ground stations), and intensive observations with aircraft, unmanned aerial vehicles, tethered balloons and radiosoundings were used. Particular emphasis was placed to bridge the different spatial scales with an integrated analysis of the observations and a complete numerical model hierarchy. This presentation will give an overview of the field experiment, with an emphasis on specific and innovative instrumental aspects, and with some preliminary results, introducing various contributions of BLLAST participants that will be shown along the 20th BLT conference.
- Published
- 2012
48. Grenslaagprocessen boven homogeen en heterogeen terrein in een mesoschaalmodel en een large eddy model
- Author
-
Braam, M., Vilà-Guerau de Arellano, J., and Górska, M.
- Subjects
Life Science - Published
- 2012
49. The response of atmospheric chemistry to dynamical boundary layer processes associated to temporal transitions and surface heterogeneity
- Author
-
Ouwersloot, H.G., Vilà-Guerau de Arellano, J., Nölscher, A.C., Krol, M.C., Ganzeveld, L.N., Breitenberger, C., Williams, J., and Lelieveld, J.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Leerstoelgroep Aardsysteemkunde ,Life Science ,Earth System Science - Abstract
Here, the mechanism behind the collapse of turbulence in the evening is investigated as a precursor to the onset of the very stable boundary layer. We study how the atmospheric boundary layer dynamics impact atmospheric chemistry, guided and constrained by observations taken above the boreal forest during the HUMPPA-COPEC-2010 campaign. Based on the vertical profiles of potential temperature and specific moisture, obtained from 132 radio soundings, the vertical stratification is determined. Data is then classified according to different prototypes of the atmospheric boundary layer. By selecting a singular day that is characterized by a convective boundary layer and using a mixed layer model, the main dynamic contributions that influence atmospheric chemistry are determined. We will present how the evolution of the boundary layer height affects the concentrations of atmospheric chemical species. Our findings show the importance of an adequate knowledge of this evolution and, consequently, the need to account for large scale dynamical forcings (subsidence, advection) in order to represent atmospheric chemistry. Extra attention is directed at investigating the impact of temporal (morning) transitions and surface heterogeneity. More specifically, we investigate the impact of mixing with a residual layer aloft during the morning transition on atmospheric chemistry. Specific observed features in the time evolutions of the NOx and O3 concentrations, like morning concentration peaks, can be explained and represented by adequately incorporating the transition of the boundary layer dynamics from nocturnal to diurnal conditions. We complete the analysis by studying the effect of surface heterogeneity and the efficiency of turbulent mixing on the chemical reactivity using a Large Eddy Simulation model. We find that under heterogeneous surface forcings boundary layers become deeper, thereby affecting the dilution capacity of the boundary layer. We will also show that local instantaneous virtual vertical profiles of temperature and chemical species concentrations obtained from the Large Eddy Simulation model deviate more from area and time averaged profiles for heterogeneous surface conditions. In addition, the influence of non-uniform turbulent mixing on the chemical reactivity in the boundary layer is studied under homogeneous and heterogeneous surface conditions. We will present a sensitivity study how this effect, quantified by the intensity of segregation, depends on the surface (e.g., length scale of heterogeneity, differences in emissions) and dynamical conditions. We find that in order to represent atmospheric chemistry in a numerical model, dynamical and chemical effects should be resolved simultaneously.
- Published
- 2012
50. Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010
- Author
-
Nölscher, A.C., Williams, J., Sinha, V., Custer, T., Song, W., Ouwersloot, H.G., and Vilà-Guerau de Arellano, J.
- Subjects
Meteorologie en Luchtkwaliteit ,tropical forest ,scots pine ,WIMEK ,model ,Meteorology and Air Quality ,ptr-ms ,organic-compound emissions ,temperature ,ambient air ,humppa-copec-2010 ,isoprene ,degradation - Abstract
Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyyti¨al¨a (Latitude 61510 N; Longitude 24170 E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyyti¨al¨a United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The comparison between these two total OH reactivity measurements, absolute values and the temporal variation have been analyzed here. Stable boundary layer conditions during night and turbulent mixing in the daytime induced low and high short-term variability, respectively. The impact on total OH reactivity from biogenic emissions and associated photochemical products was measured under “normal” and “stressed” (i.e. prolonged high temperature) conditions. The advection of biomass burning emissions to the site caused a marked change in the total OH reactivity vertical profile. By comparing the OH reactivity contribution from individually measured compounds and the directly measured total OH reactivity, the size of any unaccounted for “missing” sink can be deduced for various atmospheric influences. For “normal” boreal conditions a missing OH reactivity of 58 %, whereas for “stressed” boreal conditions a missing OH reactivity of 89% was determined. Various sources of not quantified OH reactive species are proposed as possible explanation for the high missing OH reactivity.
- Published
- 2012
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.