Old Announcements

• Regarding the final exam, 09:00-11:30 Friday 15 April in ESB 1-39:
  • There will be 32 multichoice questions (worth 16%) and two long answer (chosen from three options) for the remaining 14%. Questions cover almost all aspects of the course, with these specific exceptions:
    • LS modelling of urban dispersion; Luhar-Britter LS model of the CBL (both are aspects of the lecture of 7 April)
    • ground-air exchange and inverse dispersion (covered Thurs 31 March)
    • details of Philip's local advection model and the Rider et al. test of it (covered 22 and/or 24 March).
    • The Fokker-Planck equation
    Prodigious feats of memory will not be expected: needed equations are given.
  • When perusing past exams/midterms, bear in mind that coverage differs from year to year. For instance, the topic of radiative transport has not been covered this year.

• There will be two options for the third assignment:
  • Option A: Lagrangian simulation of the Project Prairie Grass (PPG) concentration profile using the generalized Langevin equation, for three PPG runs covering from very stable, through neutral, to very unstable stratification
  • Option B (corrected 24 Mar.): Eulerian computation of the mean wind field around a porous windbreak, based on an inhomogeneous, linearized advection-diffusion equation.

    Instructor's solution for the windbreak problem (transect along z/H=0.4).

• Assignment 2 due 17 March.

  Instructor's solutions for lab 2:

  1. Matlab solution with 5 x 5 gridpoints, i.e. Δ=0.25
  2. Matlab solution with 21 x 21 gridpoints, i.e. Δ=0.05
  3. Fortran 90 solution with 21 x 21 gridpoints, i.e. Δ=0.05; slices at y=0 and y=1/8
  4. Matlab solution with 51 x 51 gridpoints, i.e. Δ=0.02
  For gridlengths Δ=(0.25,0.05), the numerical solution should give temperature peaks (at the origin) of respectively T(0,0) ≈(0.375,0.636)^o. The analytic solution gives T(0,0)=0.6357^o. As the number of terms included in the analytical solution increases to infinity, ever shorter waves (higher wavenumbers) contribute and the analytic solution captures the "peakiness" of the delta function. In the numeric solution, the equivalent progression towards the true solution is made by refining the resolution (reducing the gridlength Δ), so that the heat source, ideally a delta function (if seen in cross section through y=0), is represented by an increasingly narrow (but higher) triangle (always preserving unit area).

• Proposed topics for 2nd half of term: (i) background for 2nd assignment (below); (ii) generalized Langevin model for atmospheric dispersion; (iii) NWP "dynamics versus physics" (as per Reynolds decomposition); (iv) overview of model dynamics (CMC's GEM & NCEP's WRF); (v) parameterization of the ABL; (vi) Cumulus parameterization; (vii) Two-stream model for solar radiation.

• Midterm exam with answers.

• Second installment of supporting booklet, eas471notes_B_26Jan2016.pdf. (There will later be an installment _C_).

• First scored lab, an Eulerian treatment of surface layer dispersion. (Updated 28 Jan. Due 23 Feb., value 15%).

• Lab 2 (unscored): a Random Displacement Model of dispersion in the atmospheric surface layer... (JDW's solution, 16000 paths).

• Lab 1 (unscored): simulating dispersion in homogeneous turbulence by the Random Displacement Model... (JDW's solution, 1000 paths).

• First installment of supporting booklet, eas471notes_A_7Jan2016.pdf. (Marked up in class 2 Feb.)

• Draft plan for topics covered and order of doing so.

Last Modified: 15 April., 2016