IO PAS CTD DATA FORMAT AND CONTENTS
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Project Description

Summer Arctic Experiment in 2002 aboard R/V Oceania was the fourteenth expedition of IO PAS in the European Arctic. The goal of this cruise was investigation of termohaline circulation, hydrography and pathways of Atlantic water in this region. The measurements described here were made with a Seabird SBE 911 plus.

Dataset Description

Data were collected north of Norwegian and south and west of Svalbard Archipelago from the continental slope to the area of sea ridges west of Spitsbergen  on Norwegian, Barents and Greenland Sea. Profiles were carried out on a grid of 205 stations. Profile data were gathered from surface to bottom. Data were obtained between 22 June and August 18, 2002.

Data collection and processing: The profiles were collected using Seabird SBE 911 plus. Data collection and processing software was SBE SEASOFT software package including:
 - SEASAVE for data acquisition
 - SEASOFT for data processing

Measured variables include pressure (db), temperature (deg C) and conductivity (S/m). The initial accuracy of the probe is 0.001 degrees C in temperature, 0.0003 S/m in conductivity and 0.015% of full scale range in pressure.

Derived variables contain potential temperature (deg C), salinity (PSU), potential density (kg/m^3), specific volume anomaly (10^-8 m^3/kg), stability (10^-8 rad^2/m) and buoyancy frequency (cycles/h).

Data Structure

Each station/cast is stored in a separate file in ASCII format. File names start with "Ar94_", indicating the cruise name (where 94 is 1994 year), and are followed by three digits indicating the cast number. The files have the extension ".cnv".

Each file contains header with detail information about measurement, names of measured and derived parameters and data processing techniques. Parameters are collected in columns with 5 db vertical resolution. All processing and post-processing operations were performed in Sea-Bird software dedicated for SBE CTD instrument.

The following significant information is included in the header:

----------- Date and time

* System UpLoad Time 

----------- Cruise and station information

** Ship:         
** Cruise:       
** Station:      
** Latitude:     
** Longitude:    
** Depth:       

----------- Measured and Derived Parameters (no.=column number - 1)

# name 0 = pr: pressure [db]
# name 1 = potemp090: potential temperature, ITS-90 [deg C]
# name 2 = sal00: salinity, PSS-78 [PSU]
# name 3 = sigma-00: density, sigma-theta [kg/m^3]
# name 4 = sva: specific volume anomaly [10^-8 m^3/kg]
# name 5 = E10^-8: stability, E [10^-8 rad^2/m]
# name 6 = N: buoyancy frequency, N [cycles/h]

-----------

Data processing sequence for SEASOFT is as follows;

        --------------------------------------------------------------------
        command   function
        --------  ----------------------------------------------------------
        datcnv    Convert raw data to engineering units, and store converted 
                  data in file.
        wildedit  Mark a data value with badflag to eliminate wild points.
        celltm    Perform conductivity thermal mass correction.
        filter    Low-pass filter columns of data.
        wfilter   Provides 4 types of window filters and a median filter
                  for data smoothing 
        loopedit  Mark a scan with badflag if scan fails pressure reversal 
                  or minimum velocity tests.
        binavg    Average data, basing bins on pressure, depth, scan number, 
                  or time range.
        derive    Calculate salinity, density, etc..
	buoyancy  Calculate buoyancy (Brunt-Vaisala) frequency and stability
        strip     Output selected columns of data from the input converted
                  data file
        --------------------------------------------------------------------

Supporting Information

For more information or assistance, please contact Institute of Oceanology
Polish Academy of Sciences at:

Powstancow Warszawy 55
81-712 Sopot, Poland
tel: (+48 58) 551 72 81 ext. 315
fax: (+48 58) 551 21 30
e-mail: ilona_g@iopan.gda.pl

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