README for the SHEBA daily averaged CTD timeseries.

Assoc. Research Professor Tim Stanton
Code OC/ST
Naval Postgraduate School
Monterey, CA 93943

Phone (831) 656 3144
FAX   (831) 656 2712
email: stanton@oc.nps.navy.mil

Overview:
     
     This CTD and microstructure profile timeseries was measured
during the SHEBA ice station field program by co-PI's Stanton,
Martinson, Morison and McPhee. An automated CTD winch repeatedly
lowered a dual sensor Sea Bird 911+ CTD from the ice depth to
150m with approximately a 10 minute cycle time. A thermal
dissipation measurement package designed by Stanton measured the
thermal dissipation rate, Chi, by measuring the microscale
thermal gradients with a pre-emphasized fp07 thermistors mounted
at the base of the CTD package sampled at 400 Hz. The
microstructure and full bandwidth CTD data stream were recorded
on a PC-based data acquisition system implemented by Jim Stockel
and Jake Yazzci of NPS, and daily summary files were forwarded by
satellite link to NPS for daily QC of all the sensors.   

     Data presented here represent daily (0000 to 23000 UT)
averages of Temperature (T) , Salinity (S), and Chi banned every
1m. These data represent a high quality first version of this
large profile timeseries, and use only pre-crusie instrument
calibrations. More comprehensive, higher resolution data sets
will be released to the web site when the full CTD and Chi
analysis has been completed. This data set does however provide a
complete view of the upper ocean structure and microstructure
during the ice station timeseries.

Location:
     The data have been placed in an anonymous ftp site on
nansen.apl.washington.edu.
Log on as anaonymous, and cd/pub/sheba/stanton/. The five ascii
files total about 2.5 Mbytes.  


Format:
     The data have been submitted to the archive as five ascii
files. While this is a bulky format, it is readily read. In these
files null values are entered as Not a Number (NaN) values, which
can be correctly read by loading into MATLAB.  The file contents
are described below.

1.)shebatime: A 351 element vector containing the day number
starting with yearday 280 in 1997. 

2.) shebadepth: A 151 element vector containing the depth for
each matrix entry in the shebaT, shebaS and shebachi files
described below.

3.) shebaT: An ascii matrix containing the temperature (degrees
C) profiles, with days in rows, and depths in columns - a 151 by
351 matrix.

4.) shebaS: An ascii matrix containing the salinity (psu)
profiles, with days in rows, and depths in columns - a 151 by 351
matrix.
5.) shebachi: An ascii matrix containing the thermal dissipation
rate (degrees C^2 / s) profiles, with days in rows, and depths in
columns - a 151 by 351 matrix.