Transcript Workshop Agenda Introduction to HYSPLIT Model Overview Special Topics
Workshop Agenda
Introduction to HYSPLIT
Introduction.ppt
Model Overview
Model_Overview.ppt
Meteorological Data
Meteorological_Data.ppt
ERA_Example.ppt
hands-on_part1.ppt
Particle Trajectory Methods
Trajectory_Methods.ppt
Real World Example – Balloon_flights.ppt
hands-on_part2.ppt
Pollutant Plume Simulations
Pollutant_Plumes.ppt
hands-on_part3.ppt
hands-on_part4.ppt
Real World Example – Arsenic.ppt
Special Topics
Special_topics.ppt
Real World Example – Volcanic_ash.ppt
hands-on_part5.ppt
Real World Example – Mercury.ppt
Extra Topics
Extra_Topics.ppt
PC-HYSPLIT WORKSHOP
PC-HYSPLIT WORKSHOP
DISPERSION MODEL CONFIGURATION
The control file (
CONTROL
) for dispersion simulations is configured from the
Concentration / Setup Run
menu tab. The concentration setup layout is identical to the trajectory menu with the exception of an additional button to set the emissions, deposition, and concentration grid (top right). The
Pollutant, Deposition and Grids setup
button will bring up a submenu (lower right) with three options (
Pollutant
,
Grids
,
Deposition
). To make modifications, enter the number of pollutants to define in the
Num
box and then click on the word
Specie #
or word
Grid #
to access the next menu.
The pollutant emission rate and deposition must be set for each pollutant.
Several independent concentration grids may be defined for each simulation. They may also be nested in space or time, if desired. Concentrations for each pollutant species are output on all grids. PC-HYSPLIT WORKSHOP
Dispersion Model Configuration
Definition of Pollutant
An arbitrary 4-character field identifies each pollutant.
The
Emission rate
is defined in mass units per hour. The actual mass unit is not specified, so for instance, if the units are kg, then concentration output will be in kg/m 3 . Any unit is acceptable, however some chemical conversion modules require specific units.
The
Hours of emission
may be defined in fractional hours.
The pollutant
Release start
can be set to any time at or after the start of the simulation. As is true for all time units, zero’s default to the simulation start time in the main menu. Zero for the month and non zero values for day and hour cause those values to be treated as relative to the simulation start time. PC-HYSPLIT WORKSHOP
Dispersion Model Configuration
Definition of Concentration Grid
Each concentration grid must be defined.
Zeros for the
grid center
default to the source location.
The
grid spacing
is especially important in concentration computations in determining the cell size (particles) or sampling resolution (puffs).
When
multiple levels
are defined, each height represents the top of the cell (particles) or actual height (puffs).
The averaging time (
Avg
) starts at the
sampling start time
for the hours/minutes specified in the output interval.
Snapshot concentrations (
Now
) are defined as the average over one time-step at the time interval specified.
Max
will save the maximum concentration at each grid point over the duration of the output interval. PC-HYSPLIT WORKSHOP
Dispersion Model Configuration
EXAMPLE DISPERSION CALCULATION
PC-HYSPLIT WORKSHOP 2-2
Run the dispersion model using these settings:
Source: St. Louis, MO,
38.75
N,
90.37
W @
10
m Meteorology:
hysplit.t12z.rucw
Emission:
6
hrs beginning
1200
UTC on
17 Feb 2009
Grid spacing
0.01
deg. lat/lon Grid span
20.0
deg. lat/lon
6
hour run time Output:
6
hr average between the ground and
100
m-agl Run Model (without SETUP) PC-HYSPLIT WORKSHOP
Example Dispersion Calculation
Results:
Change the map background file in the Concentration Display menu from
arlmap
file in the to the
\working
map_county
directory that was distributed with the workshop meteorology. Set the contours to be
UserSet
and the interval:
1.0E-10+1.0E-12+1.0E-14+1.0E-16
Set the zoom to
90
% and then display the results.
The resulting graphic should be the same as that shown (right). The noisy appearance downwind indicates that not enough particles (2500 by default) were generated to adequately represent the dispersion at later times.
PC-HYSPLIT WORKSHOP
Example Dispersion Calculation
Example Dispersion Calculation
All HYSPLIT simulations generate a text MESSAGE file, which contains diagnostic information about the calculation. Use the
Advanced/View MESSAGES
menu to view the last
MESSAGE
file. In this case (below), at the end of the simulation, 5.9999892 units of mass were still on the domain. The vertical mass distribution showed more than 80% of the mass to be within 400 m of the ground. The vertical mass distribution is computed independently of the vertical concentration grid.
PC-HYSPLIT WORKSHOP
PUFFS VS. PARTICLES
PC-HYSPLIT WORKSHOP 2-2
Modeling Particle Motion or Particle Distributions (Puffs)
To compute air concentrations it is necessary to follow all the particles needed to adequately represent the pollutant distribution in space and time. This can be done explicitly by following the trajectory of each particle, where a random component is added to the mean velocity (from the meteorological model), to define the dispersion of the pollutant cloud.
In the horizontal, the computations can be represented by the following equations:
where, X final (t + Δt) = X mean (t + Δt) + U'(t + Δt)Δt
,
U'(t + Δt) = R(Δt) U'(t) + U''(1 - R(Δt) 2 ) 0.5
, (horiz. turbulent velocity) R(Δt) = exp(-Δt/T Lu )
,
(auto-correlation coefficient) T Lu is the Lagrangian time scale, U'' = σ u λ, where λ is a random number with mean of 0 and σ of 1.
The computations can be simplified, if instead of modeling the motion of each particle, we compute the trajectory of the mean particle position and the particle distribution. The standard deviation of the particle distribution can be computed from all the particles, ______
σ 2 = (X i -X m ) 2
(
X i
= position of particle I,
X m
= mean position) or it can be computed without following individual particles by assuming a distribution shape (puff) and relationship to the local turbulence. Many different formulations can be found in the literature.
dσ h /dt = √2 σ u σ u = (K u / T Lu ) 0.5
These computations are set in the
Advanced / Configuration Setup / Concentration
menu, which modifies the
SETUP.CFG
file. PC-HYSPLIT WORKSHOP
Modeling Particle Motion or Particle Distributions (Puffs)
Note below the initial differences between the simulation using the 3D particle distribution (left) and the top-hat puff center position method (right). Without the random motion component, the top-hat puff positions follow a straight line until vertical motions or horizontal divergence begins to act on the particles. In this particular case the primary reason for the expansion of the puff-particles is that they mixed up to near 500 meters where the winds were from the south-southwest and we are seeing the differential horizontal advection acting upon the particles. 3D Particle Distribution PC-HYSPLIT WORKSHOP Top-hat Puff Center Positions
Modeling Particle Motion or Particle Distributions (Puffs)
The previous example showed a snapshot of the particle or puff center positions after 6 hours.
Air concentrations are computed by summing each particle’s mass as it passes over the concentration grid.
In the particle model mode, the concentration grid is treated as a matrix of cells, each with a volume defined by the grid dimensions. Therefore, the concentration is just the particle mass divided by the cell volume:
3D Particle: Top-Hat: Gaussian: ΔC = q(Δx Δy Δz) -1 ΔC = q(Π r 2 Δz) -1 ΔC = q(2Π σ h 2 Δz) -1 e 0.5x2/σh2
In the puff model mode, the concentration grid is considered as a matrix of sampling points, such that the puff only contributes to the concentration if it passes over the sampling point. In the puff calculation mode it is possible for a puff to pass between points and not be shown on the display:
Top-Hat: Gaussian: ΔC = q(Π r 2 Δz p ) -1 ΔC = q(2Π σ h 2 Δz p ) -1 e 0.5x2/σh2
PC-HYSPLIT WORKSHOP
Modeling Particle Motion or Particle Distributions (Puffs)
Shown below are the concentration patterns associated with the particle (left) and puff (right) distributions from the previous example. Note that the puff distribution is smoother but also initially somewhat broader. In this particular case, the horizontal puff growth equations give larger values than the particle expansion. The noisy particle distribution indicates that more than the 5000 particles used here are needed to adequately represent the horizontal distribution. 3D Particle Distribution PC-HYSPLIT WORKSHOP Top-hat Puff Center Positions
Map Background Files
Map Background Files
The
map_county
file and other high resolution map backgrounds are ASCII files containing latitude and longitude locations of map boundaries. These files can be downloaded from the NOAA ARL website at: http://ready.arl.noaa.gov/HYSPLIT_util.php
Beginning with version 4.9, many of the Postscript based plotting programs have a new option to display map backgrounds from ESRI formatted shapefiles. Multiple shapefiles can be overlaid, each with its own color and line characteristics. This shapefile option is invoked by replacing the
arlmap
field with a file called
shapefiles.txt
. This file defines the characteristics of each map shapefile to be plotted. A sample
shapefiles.txt
file and a shapefile conversion of
arlmap
is given in the
\graphics\shapefiles
subdirectory. These files should be copied to the
\hysplit4\working
directory before they are used. The color and line parameters defined in
shapefiles.txt
will give a plot comparable to the default procedure using
arlmap
.
More information can be found in the help document.
PC-HYSPLIT WORKSHOP
PC-HYSPLIT WORKSHOP
MULTIPLE SOURCES
2-2
Defining Multiple Sources
Now run the dispersion model for 2 sources using these settings:
Click
Reset
from the main menu.
Source1:
38.75
N,
90.37
W @
10
m Source 2:
38.75
N,
91.50
W @
10
m Meteorology:
hysplit.t12z.rucw
6
hour run time Emission:
6
hrs beginning
1200
on
17 Feb 2009
UTC Output:
6
hr average concentration between the ground and
100
m-agl Grid spacing
0.01
deg. lat/lon Grid span
20.0
deg. Lat/lon Run Model PC-HYSPLIT WORKSHOP
Defining Multiple Sources
Set the zoom to
70
% and display the results.
A second source added at location 38.75N and 91.50W results in two adjacent, similar plumes.
Note that the emission rate of 1 unit per hour over 6 hours is applied to each source individually and therefore the concentrations are similar to the last case.
You can view the contents of the concentration file (
cdump
) by running
Advanced / Utilities / Simple Listing
.
PC-HYSPLIT WORKSHOP
Defining Multiple Sources
An emission rate can be set for each source by including that information after the release height in the
Starting Location Setup
menu. (A fifth field can be added that sets an initial plume area in square-meters, but is only valid for “puff” simulations.) In the example shown here (top right), the emission rate of the second source has been increased to
10
units/hr To display the same concentration levels as the last graphic, make sure the
UserSet
is set to
1.0E 10+1.0E-12+1.0E-14+1.0E-16
The concentrations in the second western plume (right) have increased by the same amount as the emission increase (10%).
PC-HYSPLIT WORKSHOP
Simulation using an Emission Matrix
Emission Matrix
An emission matrix is defined using three locations; the first two locations represent the lower left and upper right grid corners, respectively, and the third location, one grid point from the lower left corner, represents the grid spacing.
Hands-on example (below): Start sources every 1 degree between the grid corners (
38.0, -92.0
) and (
41.0, -89.0
). Configure the model to run with
25000
particles per emission cycle (option 4) and increase the maximum number of particles to at least
50000
in the
Advanced / Configuration Setup / Concentration
menu.
Leave all other parameters the same as the last St. Louis example, and run the model from the
Concentration / Special Runs / Matrix
menu option (
Run using SETUP file
). Click
Continue
when asked to run the matrix. Prior to running the model, the
CONTROL
file is redefined with 16 starting locations (upper-right).
PC-HYSPLIT WORKSHOP
Simulation using an Emission Matrix
The result (top right) shows 16 plumes over a uniform 1.0 degree grid.
To make the graphic less noisy, from the
Concentration Display
menu, turn off the source location labeling and remove the black contour lines from the graphic by setting the contour outlines to
none
(see below). Execute the display to create a considerably simplified graphic (bottom right).
PC-HYSPLIT WORKSHOP
Simulation using an Emissions File
Emissions File (time-varying emissions)
In this approach, a file called
EMITIMES
is used to configure more complex point source emissions scenarios. In the standard model simulation, the
CONTROL
file can only be used to define one pollutant release cycle which applies equally to all source locations. Although multiple release cycles can be defined, they must all be at the same starting interval. With the most recent HYSPLIT update to the point source emissions file structure, multiple release locations can each have their own emission characteristics, each with different pollutants, if desired. Furthermore, multiple emission cycles, at non-regular intervals can also be defined. By appropriately locating multiple sources in space and time, line-source as well as other non-regular emissions configurations can be created. Information on the format of the emissions file and the emission text file can be found in the HYSPLIT User's Guide under
Advanced / Configuration Setup / Emissions File
(S417).
PC-HYSPLIT WORKSHOP
Simulation using an Emissions File
We will run this simulation with the 3 sources we just defined for the matrix in the
Concentration Setup
menu. (The number of source locations defined in the Setup menu must match the number of sources in the EMITIMES setup, but the location of each is overridden by the
EMITIMES
file).
From the
Advanced / Configuration Setup / Emissions File
menu enter the number of sources to define and click “
Configure Locations
.” In this case,
3
.
Next, click on the Location number to open a menu to define each source.
PC-HYSPLIT WORKSHOP
Simulation using an Emissions File
For this example, we will define 3 sources with varying emission release rates and durations (all starting at 1200 UTC February 17, 2009, which must be explicitly set as the relative convention does not apply): Source 1: 38.0 -92.0 10 m, 6 hour emission, 1000 units/hour Source 2: 39.5 -90.5 10 m, 3 hour emission, 100 unts/hour Source 3: 41.0 -89.0 10 m, 1 hour emission, 1 unit/hour Note, the GUI menu only supports the creation of an
EMITIMES
file for one pollutant for one emission cycle. If multiple pollutants are defined, or multiple cycles are required, then the file must be edited manually by duplicating the emission record at each location for all pollutants in the order they are defined in the
CONTROL
file.
PC-HYSPLIT WORKSHOP
Simulations using an Emissions File
Next, the
EMITIMES
file must be defined in the namelist (
SETUP.CFG
) file. From the
Advanced / Configuration Setup / Concentration
, select
Define EMISSION CYCLING or input file (6)
. Click on the
Default Name
button under
Optional Point Source Emission File
to set the emission file name to
EMITTIMES
. Click
Save
and
Save
again.
Run the model using SETUP file (keep all other parameters the same as the previous Matrix and St. Louis [slide 4-7] calculations).
The
EMITIMES
file (below) created in the
\hysplit4\working
directory contains information on the 3 sources just defined.
PC-HYSPLIT WORKSHOP
Simulations using an Emissions File
Before displaying the results, turn off the
Label Source
since the 3 sources defined initially in
Concentration Setup
were not the same 3 sources we defined in the
EMITIMES
file, otherwise a star will be indicated at a non-source location. Also, to reduce the clutter, set the
Contour drawing options
to
None,
set the Zoom to
100
%, and set the contour intervals to
Dyn-Exp
. The result (right) shows 3 sources with the northern-most source having the lowest concentration and the southern-most source having the largest concentration, as expected.
PC-HYSPLIT WORKSHOP
PC-HYSPLIT WORKSHOP
DISPLAY OPTIONS
2-2
Concentration and Particle Display Options • Now, we will look at the resulting particle distributions for the St. Louis Source 2 location using various source terms.
Setup the following run
:
Delete the
EMITIMES
,
emission.txt
, and
emission.asc
files from the
\hysplit4\working
directory if they exist.
Source:
38.75
N,
91.37
W @
10.0
m Meteorology:
hysplit.t12z.rucw
Emission:
6
hrs beginning
1200
UTC on
17 Feb 2009
Output: snapshot at
6
hours between the ground and
100
m-agl 3-D particle horizontal and vertical
500
particles released per cycle Dump the particles to a file called
PARDUMP
after
6
hours (menu option 9, right) Run Model (using SETUP) PC-HYSPLIT WORKSHOP
Concentration and Particle Display Options
Results:
Turn
source labeling
back on and the zoom to
80
% in the
Concentration Display
menu and execute the display.
The resulting graphic should be the same as that shown (right).
The concentration output clearly shows a noisy pattern indicating too few particles were defined to adequately represent the plume.
PC-HYSPLIT WORKSHOP
Concentration and Particle Display Options
Now, setup the following 2 runs:
Rerun the last case, but use
5000
and
50000
particles.
Make sure the maximum number of particles is >
50000
.
Although this is a snapshot (not an average over time), the particles are beginning to better define the plume, but at the expense of longer computational time.
Another option is to increase the size of the concentration grid
5,000 Particles
PC-HYSPLIT WORKSHOP
50,000 Particles
Concentration and Particle Display Options
Results:
To speed up the run without loosing the plume structure, change the type of run from a
3-D particle
to a
Top-Hat horizontal particle-vertical
and reduce the number of particles to
500
.
Turn the
contour drawing option
back to
color
from the
Concentration Display
menu.
The resulting plume (right) covers most of the footprint as the 50,000 3D particle run.
PC-HYSPLIT WORKSHOP
Concentration and Particle Display Options
Particle Display
In addition to the standard display of particle concentrations, individual particle positions can also be displayed on a map.
The
Concentration / Display / Particle
menu (right) has options to show snapshot particle distributions, assuming that the particle dump option was set in the
Advanced / Configuration Setup / Concentration
menu before running the particle simulation. Horizontal, vertical, and cross-sectional views are available.
Other options include color-coding the particles by mass size (
Mass Sizing
), by height (
Color Scale
) or output as a shapefile (
GIS
).
PC-HYSPLIT WORKSHOP 4-32
Concentration and Particle Display Options
Particle Display
Set the model configuration back to a
3 D particle
simulation with
5000
particles released, set the first output of particle dump to
6
hours (option 9), and output a 6 hour average instead of a snapshot. Run the model using SETUP file to produce a
PARDUMP
binary particle dump file in the
\hysplit4\working
directory.
Then, from the
Particle Display
menu, select the
View Type
to be
Cross section
, check the
Color Scale
option, and set the
Zoom
to
80
%.
As seen in the graphic (right), the center line of the vertical cross-section is drawn automatically based upon the particle distribution.
The particles toward the northeast are at a higher level than those closer to the source.
PC-HYSPLIT WORKSHOP 4-33
Concentration and Particle Display Options
Pointer Select Concentration Display
Another available display option is to view the concentration values directly on the grid without any interpolation through the
Concentration / Display / Concentration / Pointer Select
menu (upper right).
This option will draw the entire concentration domain as defined in the concentration grid setup menu. The
grid span
would need to be reduced to zoom in on the area of interest.
Click on the initial map domain image with the right mouse button to display the concentrations (right). In this case the full 20 x 20 degree concentration grid defined previously covers an area much larger than the plume.
Right click again to exit the display.
PC-HYSPLIT WORKSHOP 4-34
Concentration and Particle Display Options
Color Fill of the Concentration Grid
A generic PostScript equivalent to the
Pointer Select
is the
Grid Values
display option.
Grid values
runs the
gridplot
program to view the concentration values directly on the grid without any interpolation.
Gridplot was designed to plot global sized concentration grids, although any sized grid can be displayed.
The entire concentration domain will be drawn as defined in the concentration grid setup menu and there are no zoom options. The
grid span
can be reduced to zoom in on an area of interest.
Options are available to set the lowest concentration level and the contour interval.
For this example, set the
Contour base
(minimum) to
1.0E-16
with a
Contour delta
of
10.0
.
PC-HYSPLIT WORKSHOP 4-35
Converting Concentration Data to Text Files
The concentration output file is in a binary format, however there are several options available through the
Concentration / Utilities
menu that can be used to convert the concentration data to other formats.
First, prepare a multi-time period output file by setting up a simulation as in the previous example, but with the following changes:
Top-hat-horizontal particle-vertical, 500
particles,
No
particle dump interval (0),
6 hour
simulation,
1 hour
release at 1200 UTC 17 Feb 2009, and
1 hour
average concentrations.
Run with Setup.
Check the plot.
Fix-Exp
box in the
Display
menu to keep the contours constant and you may need to change the name of the output file from partplot to concplot if you last ran the particle After displaying the Postscript output, create an animated gif image by using the
Concentration / Utilities / Convert Postscript
menu by checking the
animate
and
Postscript Conversion crop
menu.
boxes in the The plume moves north and decreases in concentration. PC-HYSPLIT WORKSHOP 4-36
Converting Concentration Data to Text Files
Time Series Data Extraction
Next, select the
Concentration / Utilities / Grid to Station
menu (lower left).
Select a point downwind in the plume (
39.1N, 91.4W
), Give it a unique
Integer ID (for example 3991),
Set the
Concentration Multiplier
to
1.0
, and choose a
Log Ordinate scale
. Click
Extract Data
and an ASCII
con2stn.txt file
will be created in the
\hysplit4\working
directory with the concentration values interpolated to that location. (An input file with the station locations must be created to do multiple locations). Selecting the
Display Time Series Yes
button results in the creation of a time series plot (below right) in the
\hysplit4\working
directory called
timeplot.ps
. In this case the peak concentration occurred at 1300 UTC on 17 February 2009.
PC-HYSPLIT WORKSHOP 4-37
Converting Concentration Data to Text Files
The
Concentration / Utilities / Convert to ASCII
menu will convert every non zero grid point value to its ASCII equivalent, writing the output to one file per time period unless you specify
Single File
.
Files are labeled according to the name of the binary file, Julian day, and hour of the sampling period.
If you click
Execute Conversion
several files should be created in the
\hysplit4\working
directory. View the contents of this file for the output from the first time period (1300 UTC). This file can useful when importing the data into other mapping applications. The concentrations and depositions can be multiplied by a conversion factor with the
Conversion Options
.
PC-HYSPLIT WORKSHOP 4-38
The
Concentration / Display / Arrival
menu will plot a map of the time of arrival of the plume.
In this case, since we ran a 6 hour simulation, the
Number of contours
is set to
6
(hours). Leaving the
Time difference
as
-1
, indicates that the program will use the concentration averaging time as the default contour interval.
A
Threshold value
can also be set.
The resulting graphic shows the location of the plume at hourly intervals indicated by blue to green shading.
Time of Arrival Graphic
PC-HYSPLIT WORKSHOP 4-39