Home > Data Description > CTD Data
HOT CTD data are collected using a Sea-Bird
CTD 9/11 (9/11 Plus with dual sensors as of HOT-54) at the maximum
sampling rate of 24 samples per second (24 Hz). They are screened for
errors and processed to 2-dbar averages. Details on the CTD data acquisition
can be found in the HOT-WOCE Sampling Procedures
Manual, and details of the CTD processing for each year can be found
in the HOT Data Reports.
CTD data are written to files using formats specified by the WOCE Hydrographic Programme Office. These formats are based on NODC formats, and are detailed in the WHP Office Report WHPO 90-1, available from
Scripps Institution of Oceanography
9500 Gilman Drive
La Jolla CA 92093-0214
The files contain pressure, temperature and salinity profiles for all casts. Some casts also have dissolved oxygen, light transmission, and fluorescence. The data format consists of a self-documenting header followed by the data. The data records are written so that they can be read with a simple FORTRAN read statement. Details of this format can be found in the Readme.format file.
The first year's temperatures are reported in IPTS-68. Subsequent temperatures are reported in ITS-90 units. Since temperature sensor calibrations were done in IPTS-68 units, and the UNESCO routines require IPTS-68 temperature, all intermediate processing was done in IPTS-68. As a final step, temperature and potential temperature were converted to ITS-90 using
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t_90 = 0.99976 t_68.
A small, previously unaccounted for pressure effect on the temperature sensors that affected all of our measurements was identified at Sea-Bird Electronics Inc. in 1996. A correction for this effect (which is insignificant at levels other than in the deep and bottom waters) has been applied to all our CTD data. Another correction applied to our temperature measurements was due to viscous heating of the sensor tip due to the water flow around it (Larson and Pederson, 1996). Details on the nature of these corrections and their effect on our CTD data can be found in Temperature-Correction.
HOT
CTD data are available via this web site. Finalized
data are also available on soest.hawaii.edu's anonymous
FTP area.
-
ftp soest.hawaii.edu
Username: anonymous
Password: your e-mail address
cd hot
- in ASCII files, which can be read by all users
Subdirectories below /ctd contain the ASCII CTD data grouped according to cruise. Thus, /ctd/hot-1 contains all CTD data from HOT-1. File names are a combination of cruise, station, and cast numbers in the format hCCCaSSNN.ctd thus, h01a0205.ctd contains data from HOT-1, station 2, cast 5.
h12a0210.ctd contains data from HOT-12, station 2, cast 10.Subdirectory /aloha_mean contains cruise-averaged ASCII CTD data from the casts at station ALOHA. Files are called hotCCC.mn, where CCC is the cruise number. Files include the same variables as the CTD files, with an additional column indicating the number of casts included in each 2-dbar bin average
An additional ASCII file containing all the cruise-averaged CTD data is called year1_#ctd.dat, where # is the most recent year number. This file contains the cruise-averaged CTD temperature, salinity and dissolved oxygen from station ALOHA casts for all the cruises with finalized data. The first column in the file is Julian days since January 1st, 1988 (day 1), followed by pressure (negative dbar), sigma-theta (negative), temperature, salinity, and dissolved oxygen.
- as a Unix TAR files, which contains all CTD data from one year,
and also includes the summary files.
These files are called year#ctd.tar.Z, where the # is the year number. For instance the first year's data is in year1ctd.tar.Z. This file should be copied in binary mode, and then uncompressed with the command:
uncompress year1ctd.tar.ZThe data can then be extracted with:
tar xvf year1ctd.tarwhich will create twelve subdirectories, hot-1 to hot-12, each of which will contain the CTD data in the format described in 1. above. An additional directory cruise.summaries.1 will be created containing the summary files for these cruises.
Click on the filenames below to transfer yearly CTD data. The size of each tar file is 1.3MB-2.5MB.
Year # Cruises file to ftp 1 HOT 1-12 year1ctd.tar.Z 2 HOT 13-22 year2ctd.tar.Z 3 HOT 23-32 year3ctd.tar.Z 4 HOT 33-43 year4ctd.tar.Z 5 HOT 44-50 year5ctd.tar.Z 6 HOT 51-59 year6ctd.tar.Z 7 HOT 60-68 year7ctd.tar.Z 8 HOT 69-78 year8ctd.tar.Z 9 HOT 79-88 year9ctd.tar.Z 10 HOT 89-100 year10ctd.tar.Z 11 HOT 101-110 year11ctd.tar.Z 12 HOT 111-121 year12ctd.tar.Z 13 HOT 122-133 year13ctd.tar.Z 14 HOT 134-143 year14ctd.tar.Z 15 HOT 144-154 year15ctd.tar.Z 16 HOT 155-166 year16ctd.tar.Z 17 HOT 167-176 year17ctd.tar.Z 18 HOT 177-188 year18ctd.tar.Z 19 HOT 189-198 year19ctd.tar.Z 20 HOT 199-207 year20ctd.tar.Z 21 HOT 208-217 year21ctd.tar.Z 22 HOT 218-227 year22ctd.tar.Z 23 HOT 228-238 year23ctd.tar.Z 24 HOT 239-248 year24ctd.tar.Z 25 HOT 249-258 year25ctd.tar.Z 26 HOT 259-268 year26ctd.tar.Z 27 HOT 269-279 year27ctd.tar.Z
Download CTD data (via FTP)