HYPACT

HYbrid Particle And Concentration Transport Model

HYPACT

Features Technical overview Namelist variables Output files Execution Visualization

HYPACT Features

Meteorological and turbulence input from RAMS. Sources are defined as:

Lagrangian (particles) Eulerian (gridded concentrations) Hybrid (particles converted to concentrations)

Numerous source configurations: point, line, area, volume rectangular, ellipictal, triangular, or polygonal shapes

Gravitational settling Current version is v1.2 (v1.5 for RAMS v6.0) New version v2.0 soon. Will include history restarts and dry

deposition in standard code.

Tracer dispersion in the Lagrangian part of the HYPACT is simulated by tracking a large set of particles. Subsequent positions of each particle are computed from the relations

where u, v, and w are the resolvable scale wind components, which are obtained directly from the mesoscale meteorological model, u’, v’, and w’ are the turbulent wind components, and wp is the vertical velocity resulting from external forces.

HYPACT - Lagrangian

tuutXttX

tvvtYttY

twwwtZttZ p

HYPACT - Lagrangian

Each particle represents a discrete element of tracer mass, mp, which can vary in time due to: wet and dry deposition processes fallout (precipitation) chemical or radiological decay evaporation if droplets are considered

HYPACT - Lagrangian

Turbulent velocity components of particles representing passive tracer are derived from a first order Markov chain scheme under the following assumptions (consistent with the second-order turbulence closure in RAMS): particles are assumed to take up the same distribution of

velocities as the air; turbulence is nonhomogeneous in the vertical but is locally

homogeneous in the horizontal; turbulence is Gaussian: turbulent components of wind have

normal distributions with zero mean values and variances , and particles are assumed to move independently (one-particle

model), so the results are applicable only to ensemble-averaged diffusion.

The Markov chain scheme is defined by

where ru, rv, and rw are purely random uncorrelated components, Ru, Rv, and Rw are Lagrangian autocorrelations of wind velocity components for lag time assumed to be simple exponential functions (see tech manual).

HYPACT - Lagrangian

uuu rRttuRtu 21

vvv rRttvRtv 21

www rRttwRtw 21

HYPACT - Lagrangian

The following variables are required as an input by the above formulated Lagrangian part of the HYPACT: u, v, w - resolvable wind velocity components; σu, σv, σw - variances of wind components;

TLu, TLv, TLw - Lagrangian time scales.

Computed from TKE input from RAMS simulation

HYPACT - Eulerian

Sources defined same as for Lagrangian source, but mass contribution is given to grid cell

Advection by RAMS forward-in-time schemes Diffusion uses eddy viscosity coefficients from

RAMS simulation

HYPACT - Hybrid

Used for cases where point sources are unresolved on a grid, but the plume needs to be tracked for long distances

Reduces number of particles and numerical operations At some distance downwind from source, groups of particles

will be converted to a gridded concentration when they can be adequately resolved on the grid.

User-specified controls of the conversion process: Cluster size Horizontal and vertical dimensions

HYPACT – The H grid

HYPACT Lagrangian mode executes relative to the H grid, a single grid incorporating all RAMS nested grids.

RAMS i, j, k, and grid number defined on H grid

Provides a very efficient way to access RAMS variables.

HYPACT – The H grid

RAMS grids denoted by darker lines

HYPACT – Namelist variables

Following description is for v1.5 Similar to v1.2

HYPACT - $GENERAL

$GENERAL ihyprun=2, ! 1 = source analysis (run is stopped before the first timestep) ! 2 = dispersion run - initial start ! 3 = backward run - initial start - only lag sources metpref='./anal/a.a', ! met file location and prefix

dtpart=30., ! HYPACT timestep

maxpart=500000, ! Max total particles in run

freqavg=100., ! Interp met data time step (<=met anal freq, >=dtpart) (s)

ihturb=1, ! 1 = turb component to diffusion used, = 0 not used

iadvord=2, ! Eulerian conc advection order = 2 or 6

HYPACT - $GENERAL

! Hybrid mode control hybfreq=300., ! Cluster check time freq (s) ihybpart=40, ! Particles per cluster per source ihybmin=5, ! Min parts per cluster (below which parts are converted) hybhoriz=2., ! Horizontal length scale (fraction of horizontal grid spacing) hybvert=2., ! Vertical length scale (frac vert grid spacing, or in m if < 0) $END

HYPACT - $OUTPUT$OUTPUT hyppref='./hyt/a', ! HYPACT filename prefix

hypfreq=7200., ! Frequency of HYPACT analysis file output (s) ipartout=1, ! 1 = 0utput particle files

ieulout=1, ! Output concentrations 0 = none 1 = current 2 = average 3 = both ilagout=1, imetout=1, ! Output the meteorology 0 = no 1= yes

avgtime=900., ! Averaging time (s) (must be <= hypfreq)

ioutfmt=1, ! 1 = vfile

irgrid=0, ! r-grid concentration outputs (must be <= ihgrid) ! if irgrid > 0, specified grid ! if irgrid = 0, all grids ! if irgrid < 0, grids from abs(irgrid)

$END

HYPACT - $SPECIES$SPECIES ! Species database path/filenames (='none' no file read) ! If a species file is used, this namelist does not need to contain any further namelist ! variables. It may contain ioutspec which will otherwise default to 1 (other variables will be ! overwritten by the file values). specfile='none', ! Species name specname='TRS',':N:CO:B:2:N:','XXT', ! Molecular weight (g/mole) wgtmol=60.,44.,98., ! Mass units applied to the emission rate and ratio

units='ug','ug','ug',

HYPACT - $SPECIES

! Particle settlement 1=yes, 0=no ihfall=0,0,0,

! Particle settlement rates

szpwr=1.,1.,1., szmin=1.,1.,1., szmax=1.,1.,1., ! Include species in output 1=yes, 0=no ioutspec=1,1,1,

$END

HYPACT - $SOURCES

$SOURCES ! Source database path/filenames (='none' no file read) ! If a source file is used this namelist does not need to contain any further namelist ! variables (they will be overwritten by the file values) srcfile='none',

! Source name

srcname='Mill_1', 'Power_1', 'Power_2', 'Ponds', 'Mill_2',

! Area shape - point (poi), rectangular (rec), triangular (tri), ! irregular polygon (pol) or elliptical (ell)

shape='rec', 'tri', 'poly', 'ell', 'poi',

HYPACT - $SOURCES

! Positions of source centers (srcx=longitude, srcy=latitude)

srcy= 40.2,0.,39.7,40., 40.2, srcx= -104.2,0.,-82.7,-105.,-105.2,

! Height above ground for the center of each source (m)

srcz=50.,100.,100.,5.,50.,

HYPACT - $SOURCES

! Either: Coords of corners and height for irregular polygon shaped sources ! Or: Size dimensions of rectangular and elliptical sources (m) ! (note that the indices are important)

xsize(1)=1., ysize(1)=1., zsize(1)=1.,

polylat(1,2)=40.075,40.076,40.071, polylon(1,2)=-104.721,-104.723,-104.722, zsize(2)=10., polylat(1,3)=40.075,40.075,40.071,40.071, polylon(1,3)=-104.721,-104.723,-104.724,-104.720, zsize(3)=100.,

xsize(4)=8000., ysize(4)=8000., zsize(4)=10., ! Rotation about vert axis of rect or ellip source (deg) [+ = clockwise rot]

rotation=45.,0.,0.,30.,0.

$END

HYPACT - $EMISSIONS

!------------------- Emission Specifications -----------------------------

$EMISSIONS ! Emissions database path/filenames (='none' no file read) ! If an emissions file is used this namelist need only contain the variables iemit, isimend ! and ienddays (other variables will be overwritten by the file values). If the namelist does ! not contain these variables, all emissions will be run, and the run will go to the completion ! of the RAMS run. emfile='none', iemit=1,1,0,0,0, ! Emission scenarios: =1 run emissions ( =0 do not)

isource=2,5,1,4,3, ! Source - must be <= nsources

ispecies=2,2,2,2,2, ! Species - must be <= nspecies

HYPACT - $EMISSIONS

! Start of emission (yyyy-mm-dd-hh:mm:ss UTC)

crelstrt(1)='2000-07-30-18:00:00', crelstrt(2)='2000-07-31-00:00:00',

! Duration of emission (yyyy-mm-dd-hh:mm:ss UTC)

crelend(1) ='2000-07-30-13:00:00', crelend(2) ='2000-07-30-15:00:00',

! End of run (yyyy-mm-dd-hh:mm:ss UTC)

csimend ='2000-07-31-12:00:00', ! Source type - Lagrangian (lag), Eulerian (eul), Hybrid (hyb) or both (both)

type='both','lag','lag','both','both',

HYPACT - $EMISSIONS

! Scaling - rate (rat), total (tot), specific (spe) or absolute (abs)

scaling='rat','spe','rat','tot','tot',

! No. of particles emitted per dtpart

numparts=20,10,5,10000,1000,

! Emission rate

rate=20.,2.,1.,20.,20.,

! Mass to particle ratio ratio=1.e9,0.,0.,1.e9,1.e9,

$END

HYPACT – Output Files

All files will be prefixed with namelist variable “hyppref”. So if we assume our namelist has hyppref=‘a’,

a-spec.txt – contains source/species information for each emissions scenario (used by REVU)

a-hgrid.txt – contains grid coordinate information (used by REVU)

a-P-* (e.g., a-P-2005-08-01-121000-g0.txt) – particle output files containing locations, mass, turbulent velocities, etc.

a-C-* (e.g., a-C-2005-08-01-121000-g1.vfm) – concentration output files in same format as RAMS analysis files.

HYPACT - Execution

1. Make RAMS run

2. Prepare HYPACT namelist

3. Execute: From command line:

hypact.exe –f namelist-file HYPACT does not run in parallel Integrated RAMS-HYPACT under development

HYPACT - Visualization

REVU: NCAR Graphics plots of particles All capabilities available for concentration fields For all cases in REVU_IN:

ANPREF=‘a-C-’, CFRAME_A(1)=‘/conc_eul:1/’, ! Species number CFRAME_A(1)=‘/conc_lag:1/’, ! Species number CFRAME_A(1)=‘/part_lag:1:0/’, ! Species : source