Selected vertical sections and gridded data files in the Atlantic, Indian and Pacific Oceans

The WOCE hydrographic atlases are replacing much of this material.

Link to R. Schlitzer's eWOCE atlas

Link to WOCE Hydrographic Programme Atlas homepage (for all oceans)

Pacific Ocean

WOCE Hydrographic Programme Pacific Atlas - published 2007. Highly recommended above the sections included here.

Tables, data and section plots. All entries include gif and postscript plots of potential temperature, salinity, potential density, neutral density, and oxygen if available from the CTD data set. All entries include binary gridded files at 20km x 10 dbar resolution, and fortran programs to read the files, and to decimate or interpolate them to user-defined latitude/longitude grids.

Map of Pacific sections included here. WOCE Pacific Atlas sections are much better, but some pre-WOCE sections are shown here.

Atlantic Ocean

Map of Atlantic sections.
Map of WOCE combined A16 and A23 section.
Tables, data and section plots. Vertical section plots and bottle data files only for a large number of CTD sections and one bottle section. Mostly pre-WOCE.

Indian Ocean

WOCE Hydrographic Programme Indian Ocean Atlas (final version; under construction).

Map of Indian sections - Geosecs sections (1970s) and 32S.
Tables, data and section plots. Vertical section plots and bottle data files for one pre-WOCE CTD section, and for the Geosecs western, central and eastern sections.

Hydrographic data (CTD and discrete bottle data: oxygen, salinity and nutrients) from selected non-WOCE sections and publically available WOCE Hydrographic Program data were gridded using a modified version of Roemmich's (1983) application of objective mapping to hydrographic station data. The plots and gridded data files are a uniform set for the Pacific Ocean only. For the Atlantic and Indian, plots were made for my own use over about one year and so they are not computed uniformly; gridded data files are not available for all and so are not included yet. Prior to the end of 1996 all will be recomputed and placed online.

Downloading the postscript files: if your web browser attempts to plot the postscript files and you want to save them instead, instructions for netscape are: click with the 3rd right mouse button instead of the leftmost one and answer the dialog question.

Bottle data for each of the Atlantic and Indian sections is made available through this site, in NODC's format and in a straight ascii table which does not include all of the header information in the NODC files but which is easier to manipulate.

The public WHP data sets are available through the WHP Special Analysis Centre in Hamburg and at the WHP SAC mirror site at Scripps Institution of Oceanography.

The non-WHP CTD data sets are available in the program "ctdsearch" on the nemo data server at SIO through a public login with a menu.



The original station data were either CTD profiles, mostly at 2 dbar intervals, or discrete bottle data, with up to 36 bottles per station. The data were objectively mapped using Roemmich's (1983) method adapted for producing sections which subjectively were most like those which are hand contoured, and hence smoothed somewhat by eye.

It is assumed that the chief scientist chose appropriate horizontal sampling, with tighter spacing across regions of strong gradients.

CTD and discrete data are mapped differently to account for the sampling differences. The same decay scale and horizontal/vertical scale ratio are used for both.

CTD data: The 2 dbar profiles are first smoothed vertically with a Gaussian with half-width 10 dbar. Data are used from 6 stations at a time, and 6 depths. The mean which is removed is just that of this small rectangle.

Discrete bottle data: Data from 6 stations are used at one time. An Akima cubic spline is fit to the deepest station of the group, and this profile is removed from all stations in the group as a representation of the mean for the group. The residuals are then mapped and the mean added back in.

The programs for gridding the data are available from Lynne Talley (ltalley at ucsd edu).

Potential density calculations

The potential densities calculated relative to 0, 2000 and 4000 dbar use potential temperature referenced to these pressures and then density referenced to these pressures, respectively. The McDougall neutral density parameter is also used.


Jackett, D. R. and T. J. McDougall, 1997. A neutral density variable for the world's oceans. J. Phys. Oceanogr., 27, 237-263.
Roemmich, D., 1983. Optimal estimation of hydrographic station data and derived fields. J. Phys. Oceanogr., 13, 1544-1545.
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Lynne D. Talley, email ltalley at ucsd edu
Scripps Institution of Oceanography
University of California, San Diego
Content Last updated 21 October, 1996
Links and suggestions updated 1 October 2007