The Canadian Meteorological Centre's Atmospheric Transport and Dispersion Modelling Suite

Abstract This paper describes the integrated suite of Lagrangian transport and dispersion models in operation at the Canadian Meteorological Centre. These models have been in use for several years and are applied to many types of environmental emergencies covering spatial scales from the very local to the global. The Modèle Lagrangien Courte Distance (MLCD) is used for atmospheric spills of the order of a few kilometres. The Modèle Lagrangien de dispersion de particules d'ordre 1 (MLDP1) is normally used for events affecting areas less than 100 km; Modèle Lagrangien dispersion de particules d'ordre zéro (MLDP0) is used for events of continental and global consequences. The Modèle Lagrangien dispersion de particules mode mixte (MLDPmm) alternates between first-order and zeroth-order depending on criteria specified by the user. The theoretical bases of the models are presented, and the main algorithms used in their implementation are discussed. Modelling of the diffusion processes is based on a stochastic differential equation with the assumption of quasi-stationary Gaussian turbulence, locally homogeneous in the horizontal. The practical aspects of the operational implementation are also described. Using these models, results from simulations of real cases on scales ranging from the very local, to a few kilometres, to regional (approximately 100 km) to continental (approximately 1000 km) and to global (approximately 10,000 km) are compared and validated with available observational data.

[1]  D. Thomson,et al.  A Density Correction for Lagrangian Particle Dispersion Models , 1999 .

[2]  W. Rose,et al.  Sedimentological constraints on hydrometeor-enhanced particle deposition: 1992 Eruptions of Crater Peak, Alaska , 2009 .

[3]  Duane A. Haugen,et al.  PROJECT PRAIRIE GRASS. A FIELD PROGRAM IN DIFFUSION. VOLUME 3 , 1959 .

[4]  T. Flesch,et al.  Flow Boundaries in Random-Flight Dispersion Models: Enforcing the Well-Mixed Condition , 1993 .

[5]  F. B. Smith.  The role of wind shear in horizontal diffusion of ambient particles , 1965 .

[6]  G. W. Thurtell,et al.  Numerical simulation of particle trajectories in inhomogeneous turbulence, III: Comparison of predictions with experimental data for the atmospheric surface layer , 1981 .

[7]  F. Girardi,et al.  The field campaigns of the European Tracer Experiment (ETEX): overview and results , 1998 .

[8]  R. Draxler,et al.  Evaluation of the Transfer Coefficient Matrix (TCM) approach to model the atmospheric radionuclide air concentrations from Fukushima , 2012 .

[9]  M. Haeffelin,et al.  Impact of the transport of aerosols from the free troposphere towards the boundary layer on the air quality in the Paris area , 2008 .

[10]  Eugene Yee,et al.  Backward-Time Lagrangian Stochastic Dispersion Models and Their Application to Estimate Gaseous Emissions , 1995 .

[11]  Petra Seibert,et al.  Source-receptor matrix calculation with a Lagrangian particle dispersion model in backward mode , 2004 .

[12]  D. Thomson,et al.  Random walk modelling of diffusion in inhomogeneous turbulence , 1984 .

[13]  J. Wyngaard.  Turbulence in the Atmosphere: Contents , 2010 .

[14]  F. Nieuwstadt.  The Turbulent Structure of the Stable, Nocturnal Boundary Layer , 1984 .

[15]  R. D'amours,et al.  Application of the atmospheric Lagrangian particle dispersion model MLDP0 to the 2008 eruptions of Okmok and Kasatochi volcanoes , 2010 .

[16]  H. Yamazawa,et al.  Preliminary Estimation of Release Amounts of 131I and 137Cs Accidentally Discharged from the Fukushima Daiichi Nuclear Power Plant into the Atmosphere , 2011 .

[17]  H. Seywerd,et al.  Aerial measurement of radioxenon concentration off the west coast of Vancouver Island following the Fukushima reactor accident. , 2011, Journal of environmental radioactivity.

[18]  G. W. Thurtell,et al.  A relationship between deposition velocity and trajectory reflection probability for use in stochastic lagrangian dispersion models , 1989 .

[19]  D. Thomson.  Criteria for the selection of stochastic models of particle trajectories in turbulent flows , 1987, Journal of Fluid Mechanics.

[20]  Janusz A. Pudykiewicz,et al.  Simulation of the Chernobyl dispersion with a 3-D hemispheric tracer model , 1989 .

[21]  T. Flesch,et al.  An Idealized Mean Wind Profile for the Atmospheric Boundary Layer , 2004 .

[22]  J. Brook,et al.  Characterisation of particulate exposure during fireworks displays , 2008 .

[23]  Graeme Garner,et al.  Airborne spread of foot-and-mouth disease--model intercomparison. , 2008, Veterinary journal.

[24]  Jeffrey Weil,et al.  A Diagnosis of the Asymmetry in Top-Down and Bottom-Up Diffusion Using a Lagrangian Stochastic Model , 1990 .

[25]  John D. Wilson,et al.  Surface Delays for Gases Dispersing in the Atmosphere , 2001 .

[26]  H. C. Rodean.  Stochastic Lagrangian Models of Turbulent Diffusion , 1996 .

[27]  Charles Chree,et al.  The Relationship between the , 1925 .

[28]  E. Krasnoff,et al.  The langevin model for turbulent diffusion , 1971 .

[29]  G. W. Thurtell,et al.  Numerical simulation of particle trajectories in inhomogeneous turbulence, I: Systems with constant turbulent velocity scale , 1981 .

[30]  A. Stohl,et al.  Technical note: The Lagrangian particle dispersion model FLEXPART version 6.2 , 2005 .

[31]  Fue-Sang Lien,et al.  Bayesian inversion of concentration data: Source reconstruction in the adjoint representation of atmospheric diffusion , 2008 .

[32]  R. D'amours,et al.  A modeling assessment of the origin of Beryllium‐7 and Ozone in the Canadian Rocky Mountains , 2013 .

[33]  Spectra of concentration fluctuations: The two time scales of a meandering plume , 1986 .

[34]  Hubert Glaab,et al.  Global backtracking of anthropogenic radionuclides by means of a receptor oriented ensemble dispersion modelling system in support of Nuclear-Test-Ban Treaty verification , 2007 .

[35]  J. O'Brien,et al.  A Note on the Vertical Structure of the Eddy Exchange Coefficient in the Planetary Boundary Layer , 1970 .

[36]  Janusz A. Pudykiewicz,et al.  APPLICATION OF ADJOINT TRACER TRANSPORT EQUATIONS FOR EVALUATING SOURCE PARAMETERS , 1998 .

[37]  E. P. Korpach,et al.  Increased environmental gamma-ray dose rate during precipitation: a strong correlation with contributing air mass. , 2009, Journal of environmental radioactivity.

[38]  P. A. Durbin,et al.  A random flight model of inhomogeneous turbulent dispersion , 1980 .

[39]  D. Thomson,et al.  Calculation of particle trajectories in the presence of a gradient in turbulent-velocity variance , 1983 .

[40]  John D. Wilson.  Trajectory Models for Heavy Particles in Atmospheric Turbulence: Comparison with Observations , 2000 .

[41]  Haruyasu Nagai,et al.  Atmospheric discharge and dispersion of radionuclides during the Fukushima Dai-ichi Nuclear Power Plant accident. Part II: verification of the source term and analysis of regional-scale atmospheric dispersion. , 2012, Journal of environmental radioactivity.

[42]  E. F. Bradley,et al.  An alternative analysis of flux-gradient relationships at the 1976 ITCE , 1982 .

[43]  B. L. Sawford,et al.  Lagrangian Statistical Simulation of Concentration Mean and Fluctuation Fields. , 1985 .

[44]  F. Bonnardot,et al.  Comparison of VAAC atmospheric dispersion models using the 1 November 2004 Grimsvötn eruption , 2007 .

[45]  M. Barad,et al.  PROJECT PRAIRIE GRASS, A FIELD PROGRAM IN DIFFUSION. VOLUME II , 1958 .

[46]  M. Trainer,et al.  Nocturnal Wind Structure and Plume Growth Rates Due to Inertial Oscillations , 1997 .

[47]  E. Peake,et al.  Ozone concentrations at a remote mountain site and at two regional locations in southwestern Alberta , 1990 .

[48]  Geoffrey Ingram Taylor,et al.  Diffusion by Continuous Movements , 1922 .

[49]  Y. Delage.  A parameterization of the stable atmospheric boundary layer , 1988 .

[50]  Y. Delage,et al.  PARAMETERISING SUB-GRID SCALE VERTICAL TRANSPORT IN ATMOSPHERIC MODELS UNDER STATICALLY STABLE CONDITIONS , 1997 .

[51]  G. Swaters,et al.  Dispersion in sheared Gaussian homogeneous turbulence , 1993 .

[52]  D. A. Haugen,et al.  An experimental study of Reynolds stress and heat flux in the atmospheric surface layer , 1971 .

[53]  A. Jones,et al.  World Meteorological Organization's model simulations of the radionuclide dispersion and deposition from the Fukushima Daiichi nuclear power plant accident. , 2015, Journal of environmental radioactivity.

[54]  R. Benoit,et al.  A Finite-Element Model of the Atmospheric Boundary Layer Suitable for Use with Numerical Weather Prediction Models , 1982 .

[55]  M. Raupach,et al.  Experiments on scalar dispersion within a model plant canopy, part III: An elevated line source , 1986 .

[56]  D. Thomson,et al.  History of Lagrangian Stochastic Models for Turbulent Dispersion , 2013 .

[57]  J. Walter Strapp,et al.  An Examination of Local versus Nonlocal Aspects of a TKE-Based Boundary Layer Scheme in Clear Convective Conditions , 1999 .

[58]  R. Stull,et al.  Field Measurements of the Amount of Surface Layer Air versus Height in the Entrainment Zone. , 1987 .

[59]  B. A. Boughton,et al.  A stochastic model of particle dispersion in the atmosphere , 1987 .

[60]  M. Heikkinen,et al.  Size distribution of acidic sulfate ions in fine ambient particulate matter and assessment of source region effect , 2003 .

[61]  Hirotaka Takeuchi,et al.  The Great East Japan Earthquake (A) , 2012 .

[62]  Haruyasu Nagai,et al.  Atmospheric discharge and dispersion of radionuclides during the Fukushima Dai-ichi Nuclear Power Plant accident. Part I: Source term estimation and local-scale atmospheric dispersion in early phase of the accident. , 2012, Journal of environmental radioactivity.

[63]  David C. Pieri,et al.  The February 2001 Eruption of Mount Cleveland, Alaska: Case Study of an Aviation Hazard , 2002 .

[64]  John D. Wilson,et al.  Review of Lagrangian stochastic models for trajectories in the turbulent atmosphere , 1996 .

[65]  E. F. Bradley,et al.  Flux-Profile Relationships in the Atmospheric Surface Layer , 1971 .

[66]  Peter A. Coppin,et al.  Experiments on scalar dispersion within a model plant canopy part II: An elevated plane source , 1986 .

[67]  Gerhard Wotawa,et al.  Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition , 2011 .

[68]  C. Zerefos,et al.  A complex case study of down to the surface intrusions of persistent stratospheric air over the Eastern Mediterranean , 2006 .

[70]  P. Haan,et al.  On the use of density kernels for concentration estimations within particle and puff dispersion models , 1999 .

[71]  R. Bellasio,et al.  A statistical methodology for the evaluation of long-range dispersion models: an application to the ETEX exercise , 1998 .

[72]  Modeling the ETEX plume dispersion with the Canadian emergency response model , 1998 .

[73]  Jian Feng.  A 3-mode parameterization of below-cloud scavenging of aerosols for use in atmospheric dispersion models , 2007 .

[74]  Rory O. R. Y. Thompson.  Numeric calculation of turbulent diffusion , 1971 .

[75]  Gerhard Wotawa,et al.  Atmospheric transport modelling in support of CTBT verification—overview and basic concepts , 2003 .

[76]  E. Yee,et al.  A critical examination of the random displacement model of turbulent dispersion , 2007 .

[77]  Steven R. Hanna,et al.  Lagrangian and Eulerian Time-Scale Relations in the Daytime Boundary Layer , 1981 .

[78]  Determining cross-wind variance for low frequency wind Meander , 1998 .