CTD, Current and bottom pressure data from the Santa Barbara Channel Study

The Santa Barbara Channel study (SBC) is a closely articulated
program involving both observational and computational techniques
to obtain the best estimate of the physical oceanographic
conditions in the Santa Barbara Channel. A comprehensive
observational data set was acquired and a numerical simulation
driven by the observational data was performed. The results yield
detailed information on the Channel circulation and hydrography.

The funding agency was MMS (Department of Interior, Minerals
Management Service); the contractors, Dyanlysis of Princeton and
Science Applications International Corporation.

Regional Coverage

The CTD surveys were made within the Santa Barbara Channel and the
Santa Maria Basin, primarily along cross-shelf
transects. These transects were marked on either end by
mooring locations. The moorings have four-letter names, in
which the first two letters represent a nearby
geographical landmark (eg. "GO" for the town of Goleta),
and the last two letters indicate whether the mooring is
inshore ("IN"), offshore ("OFF"), or in the middle
("MI"). The CTD transect names are taken from the first
two letters of the appropriate moorings. See the table
below for a list of CTD transects and the associated
moorings.

Not all of the CTD casts were taken along these transects,
particularly in the early days of the project. In
addition, not all of the transects were occupied all of
the time. The AN and SM transects were occupied most
often. The transects in the Santa Maria Basin (AB, SA, and
AR) were not occupied at all until later in the Study.

Data collection
There are typically seven or eight casts per
transect, with a spacing of about 3 to 5 km per cast. The
casts go down to a maximum of about 500 m in the deepest
part of the channel. Usually all of the transects in one
particular cruise are traversed as close in time as
possible, to preserve the synoptic nature of the dataset.

CTD Cast Data

CTD cast data available from this FTP site are organized by cruise and
stored in CSA format. The cruise code is a four-digit
number where the first two digits are year, and the last
two digits are month. CSA format is an ASCII format in
which the first five lines of the file contain the header
information. Lines 1 through 3 contain the static variable
names, units, and values; lines 4 and 5 contain the
dynamic variable names and units. The rest of the file
contains the dynamic variables in columns. The filenames
use the following convention: the first four digits
represent the cruise; the next letter distinguishes
between the Neil Brown ("n") or the Ocean Sensors ("o")
CTD instrument; and the last three digits represent the
station number. For example, CTD cast #1 from Cruise 7
(cruise code 9408), taken with the Ocean Sensors CTD,
would be called 9408o001.csa.

Towed CTD Data

The towed CTD data are also organized by cruise, and are in the "tow"
subdirectories. These files are in CSA format, as
described above, but the columns and variables contained
in the files are different from the casts. The file naming
conventions are also a bit different. The first four
digits of the filename are again the cruise code, but the
next set of letters represent the transect as discussed in
the CTD introduction page. So a transect taken during
cruise 9408 along the CA transect would be called
9408ca.csa. However, if the ship was steaming from one
transect to another while the towed CTD data was being
collected, that data filename will have four letters: two
for the first transect, and two for the second. For
example, a transect between the CA and AN lines would be
called 9408caan.csa. Also, if data were taken on a
particular transect more than once, it will have a
sequence number (eg. 9408pa1.csa and 9408pa2.csa). As
mentioned on the towed CTD info page, towed data are only
available for cruises 9408, 9501, 9508, 9601, and 9603.

The Data Zoo

The Center for Coastal Studies (CCS) of the Scripps Institution of
Oceanography, University of California, San Diego, has developed an
on-line database of physical oceanographic data organized by
experiment, and referred to as the 'Data Zoo.' The animals in this
'zoo' are the individual data sets, one of which is described
above. The zoo is funded by the Mineral Management Service, Bureau
of Land Management, Department of the Interior.

Proceed to the CTD FTP Directory: "http://ccs.ucsd.edu/zoo/sbcsmb/ctd/"