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Workshop Agenda

Workshop Agenda. 4- 1. DISPERSION MODEL CONFIGURATION. 2-2. Dispersion Model Configuration.

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Workshop Agenda

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  1. Workshop Agenda PC-HYSPLIT WORKSHOP 4-1

  2. PC-HYSPLIT WORKSHOP DISPERSION MODEL CONFIGURATION 2-2

  3. 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. 3 4-3 PC-HYSPLIT WORKSHOP

  4. 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/m3.  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. 4 4-4 PC-HYSPLIT WORKSHOP

  5. 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. 5 4-5 PC-HYSPLIT WORKSHOP

  6. PC-HYSPLIT WORKSHOP EXAMPLE DISPERSION CALCULATION 2-2

  7. Example Dispersion Calculation • Run the dispersion model using these settings: • Source: St. Louis, MO, 38.75N, 90.37W @ 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) 7 4-7 PC-HYSPLIT WORKSHOP

  8. Example Dispersion Calculation • Results: • Change the map background file in the Concentration Display menu from arlmap to the map_countyfile in the \working 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. 8 4-8 PC-HYSPLIT WORKSHOP

  9. 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. 9 4-9 PC-HYSPLIT WORKSHOP

  10. PC-HYSPLIT WORKSHOP PUFFS VS. PARTICLES 2-2

  11. 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: Xfinal(t + Δt) = Xmean(t + Δt) + U'(t + Δt)Δt,where,U'(t + Δt) = R(Δt) U'(t) + U''(1 - R(Δt)2)0.5, (horiz. turbulent velocity) R(Δt) = exp(-Δt/TLu), (auto-correlation coefficient) TLu is the Lagrangian time scale, U'' = σuλ,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,        ______σ2 = (Xi-Xm)2 (Xi= position of particle I, Xm = 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.dσh/dt = √2 σuσu = (Ku / TLu)0.5 • These computations are set in the Advanced / Configuration Setup / Concentration menu, which modifies the SETUP.CFGfile. 11 4-11 PC-HYSPLIT WORKSHOP

  12. 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 Top-hat Puff Center Positions 12 4-12 PC-HYSPLIT WORKSHOP

  13. 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:      ΔC = q(Δx Δy Δz)-1 Top-Hat:           ΔC = q(Π r2 Δz)-1 Gaussian:        ΔC = q(2Π σh2 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:           ΔC = q(Π r2 Δzp)-1 Gaussian:        ΔC = q(2Π σh2 Δzp)-1 e- 0.5x2/σh2 13 4-13 PC-HYSPLIT WORKSHOP

  14. 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 Top-hat Puff Center Positions 14 4-14 PC-HYSPLIT WORKSHOP

  15. 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\shapefilessubdirectory. 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. 15 4-15 PC-HYSPLIT WORKSHOP

  16. PC-HYSPLIT WORKSHOP MULTIPLE SOURCES 2-2

  17. Defining Multiple Sources • Now run the dispersion model for 2 sources using these settings: • Click Reset from the main menu. • Source1: 38.75N, 90.37W @ 10 m • Source 2: 38.75N, 91.50W @ 10 m • Meteorology: hysplit.t12z.rucw • 6 hour run time • Emission: 6 hrs beginning 1200 UTC on 17 Feb 2009 • 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 17 4-17 PC-HYSPLIT WORKSHOP

  18. 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. 18 4-18 PC-HYSPLIT WORKSHOP

  19. 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%). 19 4-19 PC-HYSPLIT WORKSHOP

  20. Simulation using anEmission 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). 20 4-20 PC-HYSPLIT WORKSHOP

  21. 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). 21 4-21 PC-HYSPLIT WORKSHOP

  22. 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). 22 4-22 PC-HYSPLIT WORKSHOP

  23. 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. 23 4-23 PC-HYSPLIT WORKSHOP

  24. 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. 24 4-24 PC-HYSPLIT WORKSHOP

  25. 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. 25 4-25 PC-HYSPLIT WORKSHOP

  26. 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. 26 4-26 PC-HYSPLIT WORKSHOP

  27. PC-HYSPLIT WORKSHOP DISPLAY OPTIONS 2-2

  28. 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: 38.75N, 91.37W @ 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) 28 4-28 PC-HYSPLIT WORKSHOP

  29. 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. 29 4-29 PC-HYSPLIT WORKSHOP

  30. 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 50,000 Particles 30 4-30 PC-HYSPLIT WORKSHOP

  31. 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. 31 4-31 PC-HYSPLIT WORKSHOP

  32. 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). 4-32 PC-HYSPLIT WORKSHOP

  33. 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. 4-33 PC-HYSPLIT WORKSHOP

  34. 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. 4-34 PC-HYSPLIT WORKSHOP

  35. 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. 4-35 PC-HYSPLIT WORKSHOP

  36. 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 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 plot. • After displaying the Postscript output, create an animated gif image by using the Concentration / Utilities / Convert Postscript menu by checking the animate and crop boxes in the Postscript Conversion menu. • The plume moves north and decreases in concentration. 4-36 PC-HYSPLIT WORKSHOP

  37. 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. 4-37 PC-HYSPLIT WORKSHOP

  38. 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. 4-38 PC-HYSPLIT WORKSHOP

  39. Time of Arrival Graphic • 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. 4-39 PC-HYSPLIT WORKSHOP

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