scholarly journals A new Lagrangian in-time particle simulation module (Itpas v1) for atmospheric particle dispersion

2021 ◽  
Vol 14 (4) ◽  
pp. 2205-2220
Author(s):  
Matthias Faust ◽  
Ralf Wolke ◽  
Steffen Münch ◽  
Roger Funk ◽  
Kerstin Schepanski
Keyword(s):  
Boundary Layer ◽  
Particle Transport ◽  
Dispersion Model ◽  
Weather Forecast ◽  
Forecast Model ◽  
Particle Dispersion ◽  
Particle Simulation ◽  
High Temporal Resolution ◽  
Atmospheric Particle ◽  
Trajectory Models

Abstract. Trajectory models are intuitive tools for airflow studies. But in general, they are limited to non-turbulent, i.e. laminar flow, conditions. Therefore, trajectory models are not particularly suitable for investigating airflow within the turbulent atmospheric boundary layer. To overcome this, a common approach is handling the turbulent uncertainty as a random deviation from a mean path in order to create a statistic of possible solutions which envelops the mean path. This is well known as the Lagrangian particle dispersion model (LPDM). However, the decisive factor is the representation of turbulence in the model, for which widely used models such as FLEXPART and HYSPLIT use an approximation. A conceivable improvement could be the use of a turbulence parameterisation approach based on the turbulent kinetic energy (TKE) at high temporal resolution. Here, we elaborated this approach and developed the LPDM Itpas, which is coupled online to the German Weather Service's mesoscale weather forecast model COSMO. It benefits from the prognostically calculated TKE as well as from the high-frequency wind information. We demonstrate the model's applicability for a case study on agricultural particle emission in eastern Germany. The results obtained are discussed with regard to the model's ability to describe particle transport within a turbulent boundary layer. Ultimately, the simulations performed suggest that the newly introduced method based on prognostic TKE sufficiently represents the particle transport.

scholarly journals A new Lagrangian in-time particle simulation module (Itpas v1) for atmospheric particle dispersion

2020 ◽  
Author(s):  
Matthias Faust ◽  
Ralf Wolke ◽  
Steffen Münch ◽  
Roger Funk ◽  
Kerstin Schepanski
Keyword(s):  
Boundary Layer ◽  
Particle Transport ◽  
Dispersion Model ◽  
Weather Forecast ◽  
Forecast Model ◽  
Particle Dispersion ◽  
Particle Simulation ◽  
High Temporal Resolution ◽  
Atmospheric Particle ◽  
Trajectory Models

Abstract. Trajectory models are intuitive tools for airflow studies. But in general, they are limited to non-turbulent, i.e. laminar flow conditions. Therefore, trajectory models are not particularly suitable for investigating airflow within the turbulent atmospheric boundary layer. To overcome this, a common approach is handling the turbulent uncertainty as a random deviation from a mean path in order to create a statistic of possible solutions which envelops the mean path. This is well known as Lagrangian particle dispersion model (LPDM). However, the decisive factor is the representation of turbulence in the model, for which widely used models such as FLEXPART and HYSPLIT use an approximation. A conceivable improvement can be using a turbulence parameterisation approach based on the turbulent kinetic energy (TKE) on high temporal resolution. Here, we elaborated this approach and developed the LPDM Itpas, which is online coupled to the German Weather Service's mesoscale weather forecast model COSMO. It allows for benefiting from the prognostically calculated TKE as well as from the high-frequent wind information. We exemplary demonstrate the model's applicability for a case study on agricultural particle emission in Eastern Germany. The results obtained are discussed with regard to the model's ability to describe particle transport within a turbulent boundary layer. Ultimately, the simulations performed suggest that the newly introduced method based on prognostic TKE sufficiently represents the particle transport.

scholarly journals Employing Spectral Analysis to Obtain Dispersion Parameters in an Atmospheric Environment Driven by a Mesoscale Downslope Windstorm

2021 ◽  
Vol 18 (24) ◽  
pp. 13027
Author(s):  
Cinara Ewerling da Rosa ◽  
Michel Stefanello ◽  
Silvana Maldaner ◽  
Douglas Stefanello Facco ◽  
Débora Regina Roberti ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Diffusion Theory ◽  
Dispersion Model ◽  
Atmospheric Dispersion ◽  
Particle Dispersion ◽  
Atmospheric Environment ◽  
Dispersion Parameters ◽  
Simulated Concentration ◽  
Four Levels

Considering the influence of the downslope windstorm called “Vento Norte” (VNOR; Portuguese for “North Wind”) in planetary boundary layer turbulent features, a new set of turbulent parameterizations, which are to be used in atmospheric dispersion models, has been derived. Taylor’s statistical diffusion theory, velocity spectra obtained at four levels (3, 6, 14, and 30 m) in a micrometeorological tower, and the energy-containing eddy scales are used to calculate neutral planetary boundary layer turbulent parameters. Vertical profile formulations of the wind velocity variances and Lagrangian decorrelation time scales are proposed, and to validate this new parameterization, it is applied in a Lagrangian Stochastic Particle Dispersion Model to simulate the Prairie Grass concentration experiments. The simulated concentration results were shown to agree with those observed.

scholarly journals Around the world in 17 days - hemispheric-scale transport of forest fire smoke from Russia in May 2003

2004 ◽  
Vol 4 (5) ◽  
pp. 1311-1321 ◽  
Author(s):  
R. Damoah ◽  
N. Spichtinger ◽  
C. Forster ◽  
P. James ◽  
I. Mattis ◽  
...  
Keyword(s):  
Forest Fires ◽  
Transport Model ◽  
Dispersion Model ◽  
Weather Forecast ◽  
Analysis Data ◽  
Particle Dispersion ◽  
Transport Processes ◽  
Wide Field ◽  
Medium Range Weather Forecast ◽  
Model Simulations

Abstract. In May 2003, severe forest fires in southeast Russia resulted in smoke plumes extending widely across the Northern Hemisphere. This study combines satellite data from a variety of platforms (Moderate Resolution Imaging Spectroradiometer (MODIS), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Earth Probe Total Ozone Mapping Spectrometer (TOMS) and Global Ozone Monitoring Experiment (GOME)) and vertical aerosol profiles derived with Raman lidar measurements with results from a Lagrangian particle dispersion model to understand the transport processes that led to the large haze plumes observed over North America and Europe. The satellite images provided a unique opportunity for validating model simulations of tropospheric transport on a truly hemispheric scale. Transport of the smoke occurred in two directions: Smoke travelling northwestwards towards Scandinavia was lifted over the Urals and arrived over the Norwegian Sea. Smoke travelling eastwards to the Okhotsk Sea was also lifted, it then crossed the Bering Sea to Alaska from where it proceeded to Canada and was later even observed over Scandinavia and Eastern Europe on its way back to Russia. Not many events of this kind, if any, have been observed, documented and simulated with a transport model comprehensively. The total transport time was about 17 days. We compared transport model simulations using meteorological analysis data from both the European Centre for Medium-Range Weather Forecast (ECMWF) and the National Center for Environmental Prediction (NCEP) in order to find out how well this event could be simulated using these two datasets. Although differences between the two simulations are found on small scales, both agree remarkably well with each other and with the observations on large scales. On the basis of the available observations, it cannot be decided which simulation was more realistic.

scholarly journals Impact of stratospheric intrusions and intercontinental transport on ozone at Jungfraujoch in 2005: comparison and validation of two Lagrangian approaches

2009 ◽  
Vol 9 (10) ◽  
pp. 3371-3383 ◽  
Author(s):  
J. Cui ◽  
M. Sprenger ◽  
J. Staehelin ◽  
A. Siegrist ◽  
M. Kunz ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
North American ◽  
Dispersion Model ◽  
Sensitivity Study ◽  
Particle Dispersion ◽  
Threshold Values ◽  
The North ◽  
Intercontinental Transport ◽  
Stratospheric Intrusions

Abstract. The particle dispersion model FLEXPART and the trajectory model LAGRANTO are Lagrangian models which are widely used to study synoptic-scale atmospheric air flows such as stratospheric intrusions (SI) and intercontinental transport (ICT). In this study, we focus on SI and ICT events particularly from the North American planetary boundary layer for the Jungfraujoch (JFJ) measurement site, Switzerland, in 2005. Two representative cases of SI and ICT are identified based on measurements recorded at Jungfraujoch and are compared with FLEXPART and LAGRANTO simulations, respectively. Both models well capture the events, showing good temporal agreement between models and measurements. In addition, we investigate the performance of FLEXPART and LAGRANTO on representing SI and ICT events over the entire year 2005 in a statistical way. We found that the air at JFJ is influenced by SI during 19% (FLEXPART) and 18% (LAGRANTO), and by ICT from the North American planetary boundary layer during 13% (FLEXPART) and 12% (LAGRANTO) of the entire year. Through intercomparsion with measurements, our findings suggest that both FLEXPART and LAGRANTO are well capable of representing SI and ICT events if they last for more than 12 h, whereas both have problems on representing short events. For comparison with in-situ observations we used O3 and relative humidity for SI events. As parameters to trace ICT events we used a combination of NOy/CO and CO, however these parameters are not specific enough to distinguish aged air masses by their source regions. Moreover, a sensitivity study indicates that the agreement between models and measurements depends significantly on the threshold values applied to the individual control parameters. Generally, the less strict the thresholds are, the better the agreement between models and measurements. Although the dependence of the agreement on the threshold values is appreciable, it nevertheless confirms the conclusion that both FLEXPART and LAGRANTO are well able to capture SI and ICT events with duration longer than 12 h.

The Use of Large-Eddy Simulations in Lagrangian Particle Dispersion Models

2004 ◽  
Vol 61 (23) ◽  
pp. 2877-2887 ◽  
Author(s):  
Jeffrey C. Weil ◽  
Peter P. Sullivan ◽  
Chin-Hoh Moeng
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Large Eddy Simulations ◽  
Surface Source ◽  
Mean Velocity ◽  
Convective Boundary ◽  
Large Eddy ◽  
Better Than

Abstract A Lagrangian dispersion model driven by velocity fields from large-eddy simulations (LESs) is presented for passive particle dispersion in the planetary boundary layer (PBL). In this combined LES–Lagrangian stochastic model (LSM), the total velocity is divided into resolved or filtered and unresolved or subfilter-scale (SFS) velocities. The random SFS velocity is modeled using an adaptation of Thomson's LSM in which the ensemble-mean velocity and velocity variances are replaced by the resolved velocity and SFS variances, respectively. The random SFS velocity forcing has an amplitude determined by the SFS fraction of the total turbulent kinetic energy (TKE); the fraction is about 0.15 in the bulk of the simulated convective boundary layer (CBL) used here and reaches values as large as 0.31 and 0.37 in the surface layer and entrainment layer, respectively. For the proposed LES–LSM, the modeled crosswind-integrated concentration (CWIC) fields are in good agreement with the 1) surface-layer similarity (SLS) theory for a surface source in the CBL and 2) convection tank measurements of the CWIC for an elevated release in the CBL surface layer. The second comparison includes the modeled evolution of the vertical profile shape with downstream distance, which shows the attainment of an elevated CWIC maximum and a vertically well-mixed CWIC far downstream, in agreement with the tank data. For the proposed model, the agreement with the tank data and SLS theory is better than that obtained with an earlier model in which the SFS fraction of the TKE is assumed to be 1, and significantly better than a model that neglects the SFS velocities altogether.

scholarly journals The simple two-dimensional parameterisation for Flux Footprint Predictions FFP

2015 ◽  
Vol 8 (8) ◽  
pp. 6757-6808 ◽  
Author(s):  
N. Kljun ◽  
P. Calanca ◽  
M. W. Rotach ◽  
H. P. Schmid
Keyword(s):  
Boundary Layer ◽  
Dispersion Model ◽  
Regional Scale ◽  
Particle Dispersion ◽  
Real Case ◽  
Two Dimensional ◽  
Flux Footprint ◽  
Flux Tower ◽  
Wide Range ◽  
Flux Measurements

Abstract. Flux footprint models are often used for interpretation of flux tower measurements, to estimate position and size of surface source areas, and the relative contribution of passive scalar sources to measured fluxes. Accurate knowledge of footprints is of crucial importance for any upscaling exercises from single site flux measurements to ecosystem or regional scale. Hence, footprint models are ultimately also of considerable importance for improved greenhouse gas budgeting. With increasing numbers of flux towers within large monitoring networks such as FLUXNET, ICOS, NEON, or AMERIFLUX, and with increasing temporal range of observations from such towers (order of decades) and availability of airborne flux measurements, there has been an increasing demand for reliable footprint estimation. Even though several sophisticated footprint models have been developed in recent years, most are still not suitable for application to long time series, due to their high computational demands. Existing fast footprint models, on the other hand, are based on Surface Layer theory and hence are of restricted validity for real case applications. To remedy such shortcomings, we present the two-dimensional Flux Footprint Parameterisation, FFP, based on a novel scaling approach for the crosswind distribution of the flux footprint and on an improved version of the footprint parameterisation of Kljun et al. (2004b). Compared to the latter, FFP now provides not only the extent, but also the width and shape of footprint estimates, and explicit consideration of the effects of the surface roughness length. The footprint parameterisation has been developed and evaluated using simulations of the backward Lagrangian stochastic particle dispersion model LPDM-B (Kljun et al., 2002). Like LPDM-B, the parameterisation is valid for a broad range of boundary layer conditions and measurement heights over the entire planetary boundary layer. Thus it can provide footprint estimates for a wide range of real case applications. The new footprint parameterisation requires inputs that can be easily determined from, for example, flux tower measurements or airborne flux data. FFP can be applied to data of long-term monitoring programmes as well as be used for quick footprint estimates in the field, or for designing new sites.

scholarly journals Around the world in 17 days – hemispheric-scale transport of forest fire smoke from Russia in May 2003

2004 ◽  
Vol 4 (2) ◽  
pp. 1449-1471 ◽  
Author(s):  
R. Damoah ◽  
N. Spichtinger ◽  
C. Forster ◽  
P. James ◽  
I. Mattis ◽  
...  
Keyword(s):  
Forest Fires ◽  
Transport Model ◽  
Dispersion Model ◽  
Weather Forecast ◽  
Analysis Data ◽  
Particle Dispersion ◽  
Transport Processes ◽  
Wide Field ◽  
Medium Range Weather Forecast ◽  
Model Simulations

Abstract. In May 2003, severe forest fires in southeast Russia resulted in smoke plumes extending widely across the Northern Hemisphere. This study combines satellite data from a variety of platforms (Moderate Resolution Imaging Spectroradiometer (MODIS), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Earth Probe Total Ozone Mapping Spectrometer (TOMS) and Global Ozone Monitoring Experiment (GOME)) and vertical aerosol profiles derived with Raman lidar measurements with results from a Lagrangian particle dispersion model to understand the transport processes that led to the large haze plumes observed over North America and Europe. The satellite images provided a unique opportunity for validating model simulations of tropospheric transport on a truly hemispheric scale. Transport of the smoke occurred in two directions: Smoke travelling northwestwards towards Scandinavia was lifted over the Urals and arrived over the Norwegian Sea. Smoke travelling eastwards to the Okhotsk Sea was also lifted, it then crossed the Bering Sea to Alaska from where it proceeded to Canada and was later even observed over Scandinavia and Eastern Europe on its way back to Russia. This is perhaps the first time that air pollution was observed to circle the entire globe. The total transport time was about 17 days. We compared transport model simulations using meteorological analysis data from both the European Centre for Medium-Range Weather Forecast (ECMWF) and the National Center for Environmental Prediction (NCEP) in order to find out how well this event could be simulated using these two datasets. Although differences between the two simulations are found on small scales, both agree remarkably well with each other and with the observations on large scales. On the basis of the available observations, it cannot be decided which simulation was more realistic.

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