Old Announcements

• Third (and final) scored lab: Lagrangian stochastic simulation of Project Prairie Grass surface layer dispersion trials. Due: Tuesday 8 April.

• The final exam is scheduled for 09:00-11:30 on Tuesday April 15th in ESB 1-39. Note: the UA timetabling system is incapable of admitting anything but an integer for exam duration, however as announced on the course outline, 2.5 hrs will be allowed.

• On the horizon for the last quarter to a third of term: NWP models, and Canada's GEM in particular: resolved and unresolved scales of motion; model dynamics versus model physics (parameterizations); turbulent kinetic energy in the unresolved scales of motion; first order closure paradigm for unresolved transport in the ABL, as it was in Canada's (earlier) RFE (Regional Finite Element) model. Cumulus parameterization. Time permitting: modelling local advection; modelling windbreak flows. (12 Mar. 2014)
• On the horizon for second half of term: as setup for final assignment, background on "first-order" Lagrangian stochastic (LS) trajectory models, culminating in the "well-mixed condition" and (very different) "well-mixed" LS models suitable for dispersion in the ASL (turbulence treated as Gaussian) and in the CBL (convective boundary layer, vertical velocity statistics skewed). NWP models, and Canada's GEM in particular: resolved and unresolved scales of motion; model dynamics versus model physics; turbulent kinetic energy in the unresolved scales of motion; first order closure paradigm for unresolved transport in the ABL, as it was in Canada's (earlier) RFE (Regional Finite Element) model. Time permitting: modelling windbreak flows. (25 Feb.)

• The midterm exam with answers.

• The midterm exam (60 mins, 15%) will feature twelve multichoice questions (each 0.5%) and two short-answer questions (chosen from three) each worth 4.5%.

• Second scored lab: solving the steady-state, 2D heat equation using the relaxation method. Due: Friday 14 March.

• In the context of our brief discussion of the (Gaussian puff and plume) air pollution models, you may be interested in this recent article Rood (2014, in press Atmos. Environ.) comparing the performance of several regulatory models. (Note: this is not an assigned reading, purely in case you want to explore the subject.)

• Second scored lab: solving the steady-state, 2D heat equation using the relaxation method. Due: Friday 14 March.

• First scored lab: solving the advection-diffusion equation for a gas source in the atmospheric surface layer. Due: Friday 14 February.

  A few thoughts/reactions while marking lab 1:

  • when writing a technical report, it is implicit that your level of description should be sufficiently detailed as to allow a suitably qualified reader to repeat your work
  • diagrams can be an effective way to convey the essence of your computational problem -- e.g. the physical setup (defining axes, locating sources, sketching wind profile...), and the layout of the grid
  • as the PPG data are discrete, they ought to be represented as points, rather than lines, on your graph (the same is true in principle of model results, except that by manipulating Δz we could potentially have a very high density of points)
  • physical impact of the choice of Schmidt number S_c: when we decrease S_c we boost the eddy diffusivity, such that (at a given distance from the source) the emitted material has been mixed to higher heights. In accordance with that greater mixing, concentration near ground is reduced

• Comments on unscored lab 1. All reports I have seen have featured correct calculations. For forthcoming scored assignments, a couple of suggestions in regard style for your technical writing. (1) At the level of this course, there is no need to document how you computed (for instance) averages and standard deviations; in general, avoid excessive detail with respect to elements of a task you can reasonably expect your readers to trust you with. (2) Try to avoid lengthy verbal descriptions of algorithms. They can far more effectively be conveyed by a symbolic diagram, and perhaps the key equations (but see the first comment).

• Date for mid term exam: Thursday 13 February (last class before reading week). Format will be the same as for exams (see below), i.e. a mix of multichoice and short answer questions (fewer, of course, than in these final exams).

Last Modified: 18 Mar., 2014