NABOS 2002 Conductivity, Temperature, and Depth Data

Project Description
The 2002 Nansen and Amundsen Basins Observational System (NABOS) cruise aboard Russian 
conventional icebreaker Kapitan Dranitsyn was the first expedition under the NABOS framework.  The 
overarching goal is to characterize the thermohaline conditions within the continental slope of the Laptev 
Sea along with first NABOS mooring deployment. The measurements described here were made with a 
Seabird SBE-19 Plus from the. 

Data set title:	NABOS 2002 CTD profiles

PI and Data Contact:  Igor Polyakov (igor@iarc.uaf.edu), International Arctic Research Center, University 
of Alaska Fairbanks

NSF Grant: # 0327664        

Data Set Description

Data coverage:  Data were collected over a continental slope of the Laptev Sea and adjacent Arctic Ocean 
basin.  Profiles were carried out on one transect across the continental slope in the central Laptev Sea and 
on another two transects approximately orientated along the continental slope. The survey within the 
Russian Exclusive Economical Zone was conducted in accordance with authorization from the Russian 
Ministry for Industry and Science. Profile data were generally collected to a depth of 2000 m at 0.25 m 
intervals in the vertical.  Data were obtained between August 31 and September 10, 2002.

Data collection and processing: The profiles were collected using Seabird SBE-19 Plus. The winch site 
was situated at the bow of icebreaker where the influence of rotating propellers is relatively small. The 
draft of icebreaker at the position of CTD winch varies between 4 and 5 m. During CTD sounding the 
propellers were not switched off to keep the right ship position respective of the ice floes.       

Data collection and processing software was SBE SEASOFT software package for Windows. Derived 
variables include pressure (in db), temperature (in ?C) and conductivity (S/m). The design accuracy of the 
probe is 0.005 degrees C in temperature, 0.0005 S/m in conductivity and 0.1% of full scale range in 
pressure. The alignment of conductivity with respect to temperature was applied to minimize salinity spikes 
that coincide with sharp temperature steps. The empirically determined advance was –0.4 s.  The aligned 
data (pressure, temperature and salinity) from the downcasts are presented.     



Data collection problems:  Portions of the data, which were considered poor quality from the upper water 
layer, were removed. Poor quality was mainly determined by higher than normal noise levels, spikes or 
jumps in the data due to the strong impact from icebreaker in the upper water layer. Although in some cases 
the data were considered reliable lower than 4 m depth one should take into account that the noise from 
propellers and ship draft can affect the data within the upper 20-m layer. The ocean depth was reliably 
measured only within the range of 2000 m. Otherwise the depth information was obtained from the 
navigation charts. 



Data Structure

Profile Data:  The data set consists of a single ASCII character file in columnar format, containing 
multiple profiles.  Data are preceded by a fore lines file header, which identifies the data set, total number 
of casts in file, area of activity, missing value identification, year, CTD type, data source and comments. 
The following two lines after the blank describe the variables in the cast header - which are the cast 
number, latitude, and longitude of the cast, the year, Julian date, and station depth, number of points 
collected and total observed ice concentration. The next line describes the variables for the data columns - 
which are pressure (db), temperature (?C) and salinity (psu).  The data columns are followed by the cast 
header.


Supporting Information

For more information or assistance, please contact International Arctic Research Center, University of 
Alaska Fairbanks at:

930 Koyukuk Drive  
P.O.Box 757335  
Fairbanks, Alaska 99775-7335 USA 
(907) 474-2686 PHONE  
(907) 474-2643 FAX
e-mail:nabos@iarc.uaf.edu

Use of this data should be coordinated with the above PI and data contact and should reference the NABOS 
Program and PI as a data source.

To read this archive you can use the following Fortran cods:

c
c   This Fortran program reads data from NABOS
c                ctd archive.
c 
c   num    is the number of records
c   len    is the length of ctd cast
c   lat    is latitude  (degrees)
c   lon    is longitude (degrees)
c   yr     is year
c   mo     is month
c   da     is day
c   z      is level (hPa)
c   t      is water temperature (degC)
c   s      is salinity (psu)
c
c
      integer len, yr, mo, da
      real lat, lon, depth, time
      character*10 name, source
      character*180 file_in

      data file_in /'nabos03'/

      open(1,file=file_in,status='unknown')
      read(1,1) name, num
      read(1,1)
      read(1,1)
      read(1,1) source
      do lst = 1,num
       read(1,1)
       read(1,2) lat, lon, yr, mo, da
       read(1,3) len
       read(1,1)
       do i=1,len
        read(1,4) z, t, s
       enddo
      enddo 
      close(1)
 1    format(13x,a10,27x,i4)
 2    format(23x,f6.3,9x,f7.3,10x,i4,1x,i2,1x,i2)
 3    format(18x,i5)
 4    format(f7.2,2f8.3)
      end