Utilities: density and Brunt-Väisälä frequency

Graphing utility for CTD station data

This utility calculates and plots potential temperature, potential density and Brunt-Väisälä frequency as a function of depth from station data. See endd 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 scroll down for instructions.
Select the variables you wish to plot before transferring data to the applet.

Your data: depth d (m), temperature T (°C), salinity S Set the checkboxes before transferring data.

Your results: potential temperature Θ (°C) potential density (σ_Θ), Brunt-Väisälä frequency N (10^-4 s^-1)

dmin: Tmin: Smin: dmax: Tmax: Smax:

σ_Θmin: Nmin: σ_Θmax: Nmax:

Plot    T:     S:
0,13.001,35.105, 8,12.983,35.105, 10,13.002,35.108, 12,13.002,35.109, 14,13.001,35.108, 16,13.003,35.108, 18,13.002,35.108, 20,13.002,35.109, 22,13.002,35.108, 24,13.001,35.108, 26,13.002,35.108, 28,13.002,35.108, 30,13.001,35.108, 32,13.002,35.108, 34,13,35.107, 36,13.002,35.109, 38,13.002,35.108, 40,13.003,35.109, 42,13.002,35.109, 44,12.999,35.109, 46,13.002,35.109, 48,13.002,35.11, 50,13.003,35.111, 52,13.003,35.111, 54,13.004,35.111, 56,13.004,35.111, 58,13.004,35.111, 60,13.004,35.111, 62,13.003,35.111, 64,13.002,35.111, 66,13.001,35.111, 68,13.001,35.111, 70,13.002,35.11, 72,13.002,35.111, 74,13.004,35.111, 76,13.009,35.113, 78,13.004,35.111, 80,13.004,35.111, 82,13.008,35.112, 84,13.012,35.114, 86,13.016,35.115, 88,13.015,35.115, 90,13.01,35.114, 92,13.008,35.114, 94,13.011,35.114, 96,13.007,35.113, 98,13.008,35.113, 100,13.005,35.112, 102,13,35.112, 104,12.996,35.112, 106,12.981,35.109, 108,12.962,35.106, 110,12.9,35.099, 112,12.852,35.098, 114,12.816,35.094, 116,12.751,35.089, 118,12.595,35.081, 120,12.438,35.084, 122,12.389,35.084, 124,12.359,35.083, 126,12.328,35.081, 128,12.314,35.08, 130,12.287,35.077, 132,12.259,35.078, 134,12.25,35.078, 136,12.237,35.079, 138,12.22,35.078, 140,12.192,35.076, 142,12.178,35.075, 144,12.119,35.067, 146,12.08,35.063, 148,12.058,35.06, 150,12.039,35.057, 152,12.019,35.057, 154,11.993,35.054, 156,11.99,35.056, 158,11.985,35.056, 160,11.971,35.0551, 162,11.952,35.0551, 164,11.949,35.061, 166,11.954,35.066, 168,11.941,35.07, 170,11.938,35.07, 172,11.953,35.077, 174,11.975,35.083, 176,11.967,35.082, 178,11.946,35.078, 180,11.949,35.084, 182,11.938,35.085, 184,11.931,35.088, 186,11.94,35.09, 188,11.927,35.087, 190,11.909,35.083, 192,11.873,35.075, 194,11.833,35.067, 196,11.777,35.054, 198,11.65,35.031, 200,11.599,35.027, 202,11.549,35.017, 204,11.477,35.006, 206,11.438,34.997, 208,11.393,34.99, 210,11.351,34.982, 212,11.338,34.981, 214,11.312,34.976, 216,11.281,34.97, 218,11.217,34.961, 220,11.18,34.96, 222,11.16,34.96, 224,11.151,34.96, 226,11.14,34.959, 228,11.126,34.958, 230,11.111,34.957, 232,11.093,34.956, 234,11.078,34.954, 236,11.062,34.951, 238,11.046,34.948, 240,11,34.938, 242,10.962,34.933, 244,10.912,34.927, 246,10.855,34.918, 248,10.821,34.913, 250,10.791,34.908, 252,10.761,34.901, 254,10.715,34.897, 256,10.699,34.895, 258,10.679,34.892, 260,10.644,34.886, 262,10.633,34.884, 264,10.618,34.883, 266,10.655,34.898, 268,10.661,34.899, 270,10.618,34.891, 272,10.557,34.883, 274,10.527,34.878, 276,10.489,34.872, 278,10.45,34.864, 280,10.385,34.854, 282,10.313,34.842, 284,10.272,34.836, 286,10.258,34.836, 288,10.256,34.836, 290,10.257,34.836, 292,10.244,34.833, 294,10.186,34.822, 296,10.135,34.816, 298,10.077,34.806, 300,10.054,34.803,
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Θ:     σ_Θ:     N:

Verify your data against the graph.

Instructions: The utility comes with a demonstation data set as the default (the data shown in the window). To calculate density and Brunt-Väisälä frequency for the demonstration data set press SUBMIT & CALCULATE.

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 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 clears the entry field.

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

To plot the data displayed in the window select the check buttons for the variables you want to plot, press TRANSFER DATA TO APPLET and in the applet window press GRAPH.

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

Last updated 2 April 2000. Contact address: