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 (1) ◽  
pp. 1447-1487
Author(s):  
J. Cui ◽  
M. Sprenger ◽  
J. Staehelin ◽  
A. Siegrist ◽  
M. Kunz ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
North American ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Control Parameters ◽  
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. It is also shown that although the long-range transported air is characterized by relatively low NOy/CO ratios and elevated CO concentrations, using a combination of NOy/CO and CO as control parameters still encounters difficulty in distinguishing 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 sustaining time longer than 12 h.

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.

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 An Evaluation of Paired Regional/Convection-Allowing Forecast Vertical Thermodynamic Profiles in Warm-Season, Thunderstorm-Supporting Environments

2018 ◽  
Vol 33 (6) ◽  
pp. 1547-1566 ◽  
Author(s):  
Clark Evans ◽  
Steven J. Weiss ◽  
Israel L. Jirak ◽  
Andrew R. Dean ◽  
David S. Nevius
Keyword(s):  
Boundary Layer ◽  
High Resolution ◽  
Planetary Boundary Layer ◽  
North American ◽  
Mesoscale Model ◽  
Warm Season ◽  
Regional Models ◽  
The North ◽  
Nest Model ◽  
Model Pair

Abstract This study evaluates forecast vertical thermodynamic profiles and derived thermodynamic parameters from two regional/convection-allowing model pairs, the North American Mesoscale Forecast System and the North American Mesoscale Nest model pair and the Rapid Refresh and High Resolution Rapid Refresh model pair, in warm-season, thunderstorm-supporting environments. Differences in bias and mean absolute error between the regional and convection-allowing models in each of the two pairs, while often statistically significant, are practically small for the variables, parameters, and vertical levels considered, such that the smaller-scale variability resolved by convection-allowing models does not degrade their forecast skill. Model biases shared by the regional and convection-allowing models in each pair are documented, particularly the substantial cool and moist biases in the planetary boundary layer arising from the Mellor–Yamada–Janjić planetary boundary layer parameterization used by the North American Mesoscale model and the Nest version as well as the middle-tropospheric moist bias shared by the Rapid Refresh and High Resolution Rapid Refresh models. Bias and mean absolute errors typically have larger magnitudes in the evening, when buoyancy is a significant contributor to turbulent vertical mixing, than in the morning. Vertical thermodynamic profile biases extend over a deep vertical layer in the western United States given strong sensible heating of the underlying surface. The results suggest that convection-allowing models can fulfill the use cases typically and historically met by regional models in operations at forecast entities such as the Storm Prediction Center, a fruitful finding given the proposed elimination of regional models with the Next-Generation Global Prediction System initiative.

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 Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008

2011 ◽  
Vol 11 (19) ◽  
pp. 10097-10123 ◽  
Author(s):  
J. Schmale ◽  
J. Schneider ◽  
G. Ancellet ◽  
B. Quennehen ◽  
A. Stohl ◽  
...  
Keyword(s):  
Chemical Composition ◽  
North America ◽  
North American ◽  
Dispersion Model ◽  
Mean Value ◽  
Particle Dispersion ◽  
Gas Analysis ◽  
Geometric Standard Deviation ◽  
Transport Pathways ◽  
Aitken Mode

Abstract. We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB) and fossil fuel combustion (FF) plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O3 and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol in Asian FF dominated plumes was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85%) in pollution plumes than for background conditions (71%). Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatility highly oxygenated aerosol. The volume size distribution of out-of-plume aerosol showed markedly smaller modes than all other distributions with two Aitken mode diameters of 24 and 43 nm and a geometric standard deviation σg of 1.12 and 1.22, respectively, while another very broad mode was found at 490 nm (σg = 2.35). Nearly pure BB particles from North America exhibited an Aitken mode at 66 nm (σg = 1.46) and an accumulation mode diameter of 392 nm (σg = 1.76). An aerosol lifetime, including all processes from emission to detection, in the range between 7 and 11 days was derived for North American emissions.

scholarly journals Intercontinental transport of nitrogen oxide pollution plumes

2003 ◽  
Vol 3 (2) ◽  
pp. 387-393 ◽  
Author(s):  
M. Wenig ◽  
N. Spichtinger ◽  
A. Stohl ◽  
G. Held ◽  
S. Beirle ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Power Plants ◽  
Dispersion Model ◽  
Weather Conditions ◽  
Particle Dispersion ◽  
Sensor Data ◽  
Satellite Measurement ◽  
Industrial Emissions ◽  
Time Period ◽  
Intercontinental Transport

Abstract. We describe the first satellite observation of intercontinental transport of nitrogen oxides emitted by power plants, verified by simulations with a particle tracer model. The analysis of such episodes shows that anthropogenic NOx plumes may influence the atmospheric chemistry thousands of kilometers away from its origin, as well as the ocean they traverse due to nitrogen fertilization. This kind of monitoring became possible by applying an improved algorithm to extract the tropospheric fraction of NO2 from the spectral data coming from the GOME instrument. As an example we show the observation of NO2 in the time period 4--14 May, 1998, from the South African Plateau to Australia which was possible due to favourable weather conditions during that time period which availed the satellite measurement. This episode was also simulated with the Lagrangian particle dispersion model FLEXPART which uses NOx emissions taken from an inventory for industrial emissions in South Africa and is driven with analyses from the European Centre for Medium-Range Weather Forecasts. Additionally lightning emissions were taken into account by utilizing Lightning Imaging Sensor data. Lightning was found to contribute probably not more than 25% of the resulting concentrations. Both, the measured and simulated emission plume show matching patterns while traversing the Indian Ocean to Australia and show great resemblance to the aerosol and CO2 transport observed by Piketh et al. (2000).

scholarly journals Moisture Sources for the Explosive Cyclogenesis of Extratropical Cyclone Miguel (2019) through a Lagrangian Approach

2021 ◽  
Vol 8 (1) ◽  
pp. 19
Author(s):  
Patricia Coll-Hidalgo ◽  
Albenis Pérez-Alarcón ◽  
José Carlos Fernández-Alvarez ◽  
Raquel Nieto ◽  
Luis Gimeno
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Eastern Coast ◽  
Moisture Uptake ◽  
Moisture Sources ◽  
The North ◽  
Uptake Pattern

In this study, the moisture sources for the explosive cyclogenesis Miguel that occurred during 4–9 June 2019 in the North Atlantic were investigated. To determine the moisture sources, the Lagrangian FLEXPART particle dispersion model was used. The moisture uptake pattern revealed the western North Atlantic Ocean extending to north-western North America, the south-eastern coast of Greenland, and the central North Atlantic Ocean around 45° N and 50°–20° W as the main moisture sources for Miguel explosive cyclogenesis. Furthermore, the moisture uptake from these regions was higher than the climatology. During the intensification of Miguel, the moisture contribution from oceanic sources was higher than terrestrial sources. Although the total amount of atmospheric moisture achieved during the explosive intensification was similar to that absorbed the 24 h prior, they changed in intensity geographically, being more intense the local support over central and northern North Atlantic basin.

scholarly journals Water Budgets of Tropical Cyclones through a Lagrangian Approach: A Case of Study of Hurricane Irma (2017)

2021 ◽  
Vol 8 (1) ◽  
pp. 24
Author(s):  
Albenis Pérez-Alarcón ◽  
Raquel Nieto ◽  
Luis Gimeno ◽  
José C. Fernández-Alvarez ◽  
Patricia Coll-Hidalgo ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Water Vapour ◽  
Water Budget ◽  
North Atlantic Ocean ◽  
Dispersion Model ◽  
Particle Dispersion ◽  
Lagrangian Approach ◽  
Moisture Sources ◽  
The North ◽  
Hurricane Irma

This study examined the water budget of Hurricane Irma (2017) through a Lagrangian approach. To identify the moisture sources for the Hurricane Irma genesis and intensification the particle dispersion model FLEXPART was used. The North Atlantic Ocean between 15° and 30° North latitude and the South Atlantic Ocean were identified as the main moisture sources for Irma development. From the perspective of the water budget, the maximum accumulated precipitation along Irma’s trajectory coincides with the maximum water budget efficiency, which suggests that total precipitation depends largely on the water vapour supplied, rather than the storm intensity. Furthermore, the moisture supply from the surface under the area delimited by hurricane size is small, thus, the water vapour supply from the environment through the secondary circulation transports more moisture inward.

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