TY - JOUR

T1 - Footprints in homogeneously and heterogeneously driven boundary layers derived from a lagrangian stochastic particle model embedded into large-eddy simulation

AU - Steinfeld, Gerald

AU - Raasch, Siegfried

AU - Markkanen, Tiina

N1 - Funding Information: Acknowledgements This study was supported by the German Science Foundation (DFG) under grants RA-617/16-1,2. All calculations have been performed on the IBM Regatta P690 series of the “Norddeutscher Verbund für Hoch-und Höchstleistungsrechnen” (HLRN) in Hannover/Berlin, Germany. We would like to thank J. C. Weil for providing the raw data of his validation experiments to us and T. Foken for many fruitful discussions. Finally, we are grateful to the anonymous reviewers whose comments helped us a lot to improve the initial manuscript.

PY - 2008/9/30

Y1 - 2008/9/30

N2 - A Lagrangian stochastic (LS) model, which is embedded into a parallelised large-eddy simulation (LES) model, is used for dispersion and footprint evaluations. For the first time an online coupling between LES and LS models is applied. The new model reproduces concentration patterns, which were obtained in prior studies, provided that subgrid-scale turbulence is included in the LS model. Comparisons with prior studies show that the model evaluates footprints successfully. Streamwise dispersion leads to footprint maxima that are situated less far upstream than previously reported. Negative flux footprints are detected in the convective boundary layer (CBL). The wide range of applicability of the model is shown by applying it under neutral and stable stratification. It is pointed out that the turning of the wind direction with height leads to a considerable dependency of source areas on height. First results of an application to a heterogeneously heated CBL are presented, which emphasize that footprints are severely affected by the inhomogeneity.

AB - A Lagrangian stochastic (LS) model, which is embedded into a parallelised large-eddy simulation (LES) model, is used for dispersion and footprint evaluations. For the first time an online coupling between LES and LS models is applied. The new model reproduces concentration patterns, which were obtained in prior studies, provided that subgrid-scale turbulence is included in the LS model. Comparisons with prior studies show that the model evaluates footprints successfully. Streamwise dispersion leads to footprint maxima that are situated less far upstream than previously reported. Negative flux footprints are detected in the convective boundary layer (CBL). The wide range of applicability of the model is shown by applying it under neutral and stable stratification. It is pointed out that the turning of the wind direction with height leads to a considerable dependency of source areas on height. First results of an application to a heterogeneously heated CBL are presented, which emphasize that footprints are severely affected by the inhomogeneity.

KW - Convective boundary layer

KW - Footprint

KW - Lagrangian stochastic model

KW - Large-eddy simulation

KW - Neutral boundary layer

KW - Stable boundary layer

UR - http://www.scopus.com/inward/record.url?scp=54049085281&partnerID=8YFLogxK

U2 - 10.1007/s10546-008-9317-7

DO - 10.1007/s10546-008-9317-7

M3 - Article

AN - SCOPUS:54049085281

VL - 129

SP - 225

EP - 248

JO - Boundary-Layer Meteorology

JF - Boundary-Layer Meteorology

SN - 0006-8314

IS - 2

ER -