Graphing utility for geostrophic currents

This utility calculates and plots the geostrophic current and volume transport between two hydrographic (CTD) stations, relative to the deepest observation, as a function of depth. See end of page for instructions.

This page combines JavaScipt with a Java applet. See the Utilities entry page for details on browser requirements.

To use the demonstration data press SUBMIT & CALCULATE.
To enter own data press ENTER OWN DATA and follow the instructions.

Station 1: latitude longitude       Station 2: latitude longitude
Your data: depth d (m),
station 1: temperature T (°C), salinity S
station 2: temperature T (°C), salinity S


Your result:
velocity vg(m s-1)
volume transport VT (Sv)
  dmin:  dmax:
 vgmin: vgmax:
VTmin: VTmax:

 back    forward

Verify your data
against the graph.

Instructions: The utility comes with a demonstation data set from the North Atlantic Ocean as the default (the data shown in the window). To calculate the geostrophic current and volume transport for the demonstration data set press SUBMIT & CALCULATE. The station positions are shown when the calculation is done.

To enter own data press ENTER OWN DATA and follow the instructions that will appear in the window. Select the entire window text and replace it with your data, either by typing the data directly into the window as depth (m), temperature (°C), salinity, temperature (°C), salinity for the two stations, separated by commas and one group per line, or by pasting data in from a spreadsheet or text processor. When all data in the window are complete press SUBMIT. This produces a display of the data as they are accepted by the programme. Press RESTORE DATA to return to the data in their original form if further editing is required. RESET returns to the default data set.

You can scroll through long data sets by pressing the > and < buttons.

To plot the data displayed in the window press TRANSFER and in the applet window press GRAPH. You can zoom in on parts of the graph by entering new depth, velocity and volume transport limits and pressing NEW SCALES, then GRAPH. Pressing DEFAULT SCALES resets the axes to 0 - 5000 m, -2 to +2 m/s and -50 to 50 Sv.

To edit a graph edit the data in the window on the left, press RESET in the applet (!) and repeat the plotting procedure.


© 2001 M. Tomczak
Graphing applet © 2000 Mariusz Bajger

Last updated 2 April 2001.

contact address: