Theory & Concepts for Atmospheric Dispersion
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Overview
Spreadsheet comparing features of AERMOD, HYSPLIT, CALPUFF, & CMAQ. (Apr 2024)
- Quick overview of turbulence theory, boundary-layers & diffusion theory
(See Stull, 2017, Practical Meteorology (PrMet),
Chapter 18 Atmospheric Boundary Layers &
Chapter 19 Pollutant Dispersion).
The notation below refers to section numbers in those chapters.
- PrMet 19.0 - 19.2. Intro, terminology, air qual standards. Also BC AirQual Stds.
- Discussion: Passive tracers. Role of turbulence vs. molecular diffusion.
- Superposition of eddies. Shear generation. Buoyant generation.
Deeper convection1. Deeper convection2.
- Discussion of spectrum of eddy sizes. Richardson's poem. ScanSet A p3.
- Turbulent timeseries.
- Turbulence statistics BCMoE talk 2017 p39-60 ; & [PrMet 18.6 Turb (but not last page)] .
- Smoke is emitted into Atmos. Boundary Layers (ABL), and ABLs are often turbulent.
- PrMet 18.0-18.5 ABLs .
- Governing eqs., flux, stress, eddy flux, Reynolds stress, scaling variables, similarity theory
- PrMet 19.3 stable vs neutral vs unstable ABLs. Pasquill-Gifford.
- Gaussian Plumes
- PrMet 19.4.1. Plume snapshot vs time average.
- From 1-D Gaussian puff (ScanSet B) to 3-D Gaussian plumes (ScanSet C)
(and their relationship to AERMOD and HYSPLIT)
- Taylor's statistical theory (ScanSet D) . Demo of autocorrelation.
- Meaning and widespread use of Lagrangian autocorrelation R
- Sigma-y and sigma-z
- Applications
- Homework: Gaussian plume for neutral PBL.
- Dispersion in Convective Boundary Layers (Deardorff)
- Similarity theory overview from Intro to BL Meteorology chapter 9 (ScanSet E),
and the Handbook of similarity functions
- Movie of Willis & Deardorff convection tank experiments (download first, then play)
- Convective similarity for pollutant dispersion (ScanSet F)
- Interpretation of dimensionless variable "X"
- Stull's fit to Deardorff convective dispersion (PrMet 19.7)
- Homework: Deardorff smoke dispersion in convective PBL
- Plume Rise
- Briggs & Weil plume rise derivations (ScanSet G)
- Photographic evidence of lateral entrainment into rising smoke plumes ( lab1 , lab2 , lab3 , volcanic ).
- Of historical note (not assigned here): B.R.Morton, G.Taylor, J.S.Turner, 1956: Turbulent gravitational convection from maintained and instantaneous sources. Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences,Volume 234, Issue 1196, Jan 1956. p1-23. https://royalsocietypublishing.org/doi/epdf/10.1098/rspa.1956.0011
- Lagrangian particle dispersion
- Concept of Advection by the mean wind. Banff movie (download, then play) & COMET demo
- Trajectories vs streamlines vs streaklines
- Eqs. used in Hysplit. (see BAMS paper eqs 2 & 3 and Hysplit arl-224 Tech Memo in the HYSPLIT section of this course)
- Advection equation: (See BAMS paper eq 1). Demo with advection worksheet.
- I cover the BAMS supplement section 1 only (Transport and Dispersion, eqs ES1 - ES6), & introduct the Langevin eq.
- Weighting of inertia vs. random using autocorrelation, R .
- Class presentations on the remainder of the BAMS supplement.
- Turbulent dispersion of particles discussed in the BAMS supplement - homeworks for the students
- Similarity eqs. for sigma-u,v,w . (& Homework)
- Write your own 1-D Lagrangian particle model (homework)
- Write your own 2-D Lagrangian particle model (homework)
- Turbulence kinetic energy (TKE)
- Turbulent dispersion of puffs
- CALPUFF
- Slugs (Gaussian packets of pollutants stretched in the along-wind direction, as used in CALPUFF) (ScanSet H) .
- Clarification of the "causality" function "F" in the definition of slugs.
- ScanSet I - Discussion of CAPUFF Tech Manual sections 2.2.4 (Puff splitting) , 2.2.5 (Convective Deardorff pdfs) , 2.5 (Coastal) .
- Smog
- XXX
- XXX
Other Info
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http://www.eos.ubc.ca/courses/atsc507/ADM/
Last updated 10 Apr 2024.
Copyright © 2016, 2018, 2024 by Roland Stull.