The trajectory model input control file can be created using any text editor. However if the GUI is not being used, it would be easier to let the model create the initial file based upon standard output prompts. These are described in more detail below. When data entry is through the keyboard (a file named CONTROL is not found), a STARTUP file is created. This contains a copy of the input, and which later may be renamed to CONTROL to permit direct editing and model execution without data entry. If you are unsure as to a value required in an input field, just enter the forward slash (/) character, and the indicated default value will be used. This default procedure is valid for all input fields except directory and file names. An automatic default selection procedure is also available for certain input fields of the CONTROL file when they are set to zero. Those options are discussed in more detail below. Each input line is numbered (only in this text) according to the order it appears in the file. A number in parenthesis after the line number indicates that there is an input loop and multiple entry lines may be required depending upon the value of the previous entry.
1- Enter starting time (year, month, day, hour, {minutes optional})
Default: 00 00 00 00 {00}
Enter the two digit values for the UTC time that the calculation is to start. Use 0's to start at the beginning (or end) of the file according to the direction of the calculation. All zero values in this field will force the calculation to use the time of the first (or last) record of the meteorological data file. In the special case where year and month are zero, day and hour are treated as relative to the start or end of the file. For example, the first record of the meteorological data file usually starts at 0000 UTC. An entry of "00 00 01 12" would start the calculation 36 hours from the start of the data file. The minutes field is optional but should only be used when the start time is explicitly set to a value.
2- Enter number of starting locations
Default: 1
Simultaneous trajectories can be calculated at multiple levels or starting locations. Specification of additional locations for certain types of simulations can also be accomplished through the Special Simulations menu tab, or through manual editing of the CONTROL file and running the model outside of the GUI. When multiple starting locations are specified, all trajectories start at the same time. A multiple trajectory in time option is available through the Advanced menu through a namelist file parameter setting.
3(1)- Enter starting location (lat, lon, meters)
Default: 40.0 -90.0 50.0
Trajectory starting position in degrees and decimal (West and South are negative). Height is entered as meters above ground-level. An option to treat starting heights as relative to mean-sea-level is available through the Advanced menu through a namelist file parameter setting.
4- Enter total run time (hours)
Default: 48
Specifies the duration of the calculation in hours. Backward calculations are entered as negative hours. A backward trajectory starts from the trajectory termination point and proceeds upwind. Meteorological data are processed in reverse-time order.
5- Vertical motion option (0:data 1:isob 2:isen 3:dens 4:sigma 5:diverg 6:msl2agl 7:average 9: fix-up&down 10: fix-down)
Default: 0
Indicates the vertical motion calculation method. The default "data" selection will use the meteorological model's vertical velocity fields; other options include {isob}aric, {isen}tropic, constant {dens}ity, constant internal {sigma} coordinate, computed from the velocity {diverg}ence, vertical coordinate remapping from MSL to AGL, an option to spatially average the vertical velocity, and two options allowing user-specified fixed vertical velocities. In the averaging option (7), the averaging distance is automatically computed from the ratio of the temporal frequency of the data to the horizontal grid resolution.
While not yet available in the GUI, the user-specified fixed-velocity option with both up and down motion (9) requires the user to also set the rise (WBWR) and fall (WBWF) velocities (m/s) and the height at which the motion changes from up to down (WBBH) (m) in the SETUP.CFG file. This mode could be used to simulate a weather balloon with known upward and downward velocities and a known burst height. The downward velocity (WBWF) is specified as a positive number even though the motion is downward. The burst height (WBBH) is meters above ground level unless the advanced parameter KMSL is set to 1 to indicate meters above mean sea level. The top of the model domain (next parameter) must be greater than WBBH. In the fixed-downward- motion-only mode (10) (also not available yet in GUI), the user must simply specify the downward velocity (WBWF, m/s) in the SETUP.CFG file. In both of these trajectory-only "weather balloon" modes, the simulation stops once the trajectory hits the ground, even if the total run time is longer than this. Also, since a typical weather-balloon flight (e.g., with WBWR=4.0 m/s, WBWF=10.0 m/s, and WBBH=20000.0 m-agl) is only 1-2 hrs, it is recommended that the trajectory endpoint output frequency be set to 1 minute in the SETUP.CFG file (TOUT=1) to provide output information with sufficient time resolution.6- Top of model domain (internal coordinates m-agl)
Default: 10000.0
Sets the vertical limit of the internal meteorological grid. If calculations are not required above a certain level, fewer meteorological data are processed thus speeding up the computation. Trajectories will terminate when they reach this level. A secondary use of this parameter is to set the model's internal scaling height - the height at which the internal sigma surfaces go flat relative to terrain. The default internal scaling height is set to 25 km but it is set to the top of the model domain if the entry exceeds 25 km. Further, when meteorological data are provided on terrain sigma surfaces it is assumed that the input data were scaled to a height of 20 km (RAMS) or 34.8 km (COAMPS). If a different height is required to decode the input data, it should be entered on this line as the negative of the height. HYSPLIT's internal scaling height remains at 25 km unless the absolute value of the domain top exceeds 25 km.
7- Number of input data grids
Default: 1
Number of simultaneous input meteorological files. The following two entries (directory and name) will be repeated this number of times. A simulation will terminate when the computation is off all of the grids in either space or time. Trajectory calculations will check the grid each time step and use the finest resolution input data available at that location at that time. When multiple meteorological grids have different resolution, there is an additional restriction that there should be some overlap between the grids in time, otherwise it is not possible to transfer a trajectory position from one grid to another. If multiple grids are defined and the model has trouble automatically transferring the calculation from one grid to another, the sub-grid size may need to be increased to its maximum value.
While not available in the GUI, if the user is creating the CONTROL file themselves, two numbers can be specified here: the first being the number of unique grids and the second being the number of files in each grid. For example, an entry of 2 12 would mean that there are met files for 2 different grids (e.g., a regional and a global grid), and that there are 12 files being specified for each grid. The grids should be specified in order of resolution, with the highest resolution grids (i.e, the smallest horizontal spacing between grid points) being specified before lower resolution grids. The two entries for each file (directory and filename) are repeated for each file in the first grid, and then for each file in the second grid, and so on, for any subsequent grids. Note that the same number of files are required for each grid in this approach. Without the use of this approach (i.e., when only one number is specified) the maximum number of files that can be used in the simulation is relatively small, but with this second approach, a much larger number of files can be used in the simulation.
8(1)- Meteorological data grid # 1 directory
Default: ( \main\sub\data\ )
Directory location of the meteorological file on the grid specified. Always terminate with the appropriate slash (\ or /).
9(2)- Meteorological data grid # 1 file name
Default: file_name
Name of the file containing meteorological data. Located in the previous directory.
10- Directory of trajectory output file
Default: ( \main\trajectory\output\ )
Directory location to which the text trajectory end-points file will be written. Always terminate with the appropriate slash (\ or /).
11- Name of the trajectory endpoints file
Default: file_name
The trajectory end-points output file is named in this entry line.