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