PCTides Lab Exercise

Objectives:

Procedures:

Note: Before you start this exercise, make sure you have a printed copy of these instructions available since the model interface takes over the entire pc screen.

Start up the PCTides program by either clicking on the desktop icon for pctides, or by clicking on your pc's "Start" button, and then selecting "relocatable model / PC Tides". You should now see the screen shot in Figure 1, with the menu bar across the top.

The general procedure in setting up and running PCTides is to work across the buttons at the top, from left to right. The instructions below are a quick guide to help you work through the model setup quickly.

For more detailed directions, please consult the User Manual for PCTides (Word doc). The words in bold blue refer to choices you should make through the drop-down menus. Choices that are made from a submenu are indented. The regular text refers to actions you need to take.

Set up domain (grid) and bathymetry:

Grid Setup
        Generate grid bathymetry
              Interactive rubberband
                  Zoom to area of interest (You may need to first "Unzoom all" under Zoom to get back to the global domain).

GEMS
        Create topography grid
        Click and drag over desired domain
        Enter grid file name
        Choose # of grid cells (<200) for spatial resolution about 10 km (~0.1o)
        OK
        Toggle between depths and cell in upper left corner
        Close grid generation program by clicking x on upper right
        Activate GCOMMENU.exe on bottom taskbar
        Type in name of grid file
        Hit escape - this creates topography and bathymetry file
        Check that the bathymetry looks okay. To do that, starting at the top menu level:

Output
        Bathymetry
           Use defaults
                Full grid
While you've got the bathymetry on the screen, note the coordinates for locations where you'd like to specify a station.
Hit Return to get back to the menu

Get Boundary Conditions for the open boundaries:

Grid Setup
        Get tides

Again, you can check to see that you got some tide data for the boundary conditions at this point: Output
        Tidal BC
            m2.dat
                Put observations - Y
                    Enter
                        Enter
                            Enter
                                Enter
                                    Enter

Wind forcing

We are not going to use the Winds part, but this is available if you want to use wind forcing.

Model Parameters and specifying Stations for output: (Tab to move between input boxes, Esc when finished):

Model Input
        Parameters:
            wind 0
            tide 2
            nesting 0
            screen 1
            inundation 0
           
            output time 3
            step
            max time 48
            Start time and time zone

        Stations:
            Enter latitude and longitude for station locations
            Output bathymetry plot again (optional) to view station locations on map

Run the Model

Model
        Tide Model

View the Output

Output
        Currents - lets you plot sea level and current maps
        Time series of height, speed, direction at specified stations
            Enter name of time series file (choose from displayed list)
            Meters or feet?
            Overlay plot? (no)
            Current speed time series
            Current direction time series

The output plots may be printed using PrtSc. Look at the time series plot of height. Using this plot, determine the tidal range for the location chosen (difference in height between min and max). What is the time predicted for the maximum height? Is the tidal signal at this location predominantly diurnal, semidiurnal, or mixed?

You have now successfully set up the domain, boundary conditions, forcing, and model parameters for the PCTides model. The model has additional capabilities such as importing more complicated bathymetry and winds. We encourage you to consult the User Manual (PDF file) to become more familiar with the model's capabilities if you are using PCTides operationally.

Next, you will have a chance to compare the tidal predictions at a single location using PCTides, ADCIRC, and GFMPL. Continue on to the Tides Exercise