
NODC DOCUMENTATION FOR CTD DATASETS

#documentation_file_name:            *     
#nodc_accession_number:              *
#nodc_reference_number:              * 
#nodc_documentation_date:            *
#nodc_documentor: 		     *                    
#distribution_restriction:           none
#date_received:                      *
#submission_medium: ftp tar file	
#submittor_name:  Robert O'Malley
#submittor_institution: College of Oceanic and Atmosperic Sciences,
			Oregon State University
#submitter_street_address: 104 Ocean Admin Bldg
#submitter_city: Corvallis 
#submitter_state: Oregon
#submitter_country: USA
#submitter_zip_code:  97331-5503
#sumitter_telephone_no: 541-737-2180
#submitter_internet: omalley@oce.orst.edu
#submitter_email:
#collection_information (i.e cruise dates, ports, cast numbers, 
 time of cast, longitude and latitude of casts):
 Wecoma cruise W9605A
 10 May to 15 May, 1996
 Newport to Newport, Oregon
 Seasoar sampling in six tows during W9605A (test cruise) as follows:

Tow no. Start date,time(UTC)  End date,time(UTC)      Parameters measured
  1       12 May 1028           12 May 1743            P, T1, C1, T2, C2
  2       12 May 1803           12 May 2211            P, T1, C1, T2, C2
  3       13 May 1219           13 May 1407            P, T1, C1, T2, C2
  4       14 May 0440           14 May 1703            P, T1, C1, T2, C2
  5       14 May 2059           14 May 2243            P, T1, C1, T2, C2
  6       15 May 0104           15 May 0919            P, T1, C1, T2, C2

 All observations were in the area between 42.5 degrees N. and 43.4
 degree N., and between 124.5 degrees W. and 125.2 degrees W.
 Maximum sampling depth usually less than 130 m for all tows.
#principal_investigator_name: John A. Barth
#pi_institution:College of Oceanic and Atmosperic Sciences, 
    	       	Oregon State University 
#pi_street-address:  104 Ocean Admin Bldg
#pi_city: Corvallis
#pi_state: Oregon
#pi_country: USA
#pi_zip_code: 97331-5503
#pi_telephone_no: 541-737-1607
#pi_internet: barth@oce.orst.edu
#pi_email:
#project: Coastal Jet Separation (CJS) and Coastal Mixing and Optics (CMO) 
          experiments
#funding agency: NSF (for CJS) and ONR (for CMO)
#grant/contract-no: NSF Grant OCE-9314370 and ONR Grant N00014-95-1-0382
#platform_type: research vessel
#platform_name: Wecoma
#collection_methods:  
 (i.e. how were the data obtained) 
 SeaBird 9/11 plus CTD inside Seasoar vehicle; with dual ducted SBE-3 and SBE-4
 temperature and conductivity sensors inside seasoar vehicle; flow through 
 sensor duct pumped by SBE-5 pumps; intake and outlet for each sensor pair was 
 directed forward through center of lower nose with intake and outlet 
 separated by about 2 cm, the T1-C1 pair were starboard of the centerline,
 and the T2-C2 pair were port of the centerline; final data were all from
 the T1-C1 pair with the exception of the last hour of tow 1 when the
 T1-C1 pair were clogged; final data were from the following pairs of 
 sensors:  

	Tows 1-2:  SN 1384 and 1538 for T and C
	           (SN 1008 and 1070 for T and C at end of Tow 1)

	Tows 3-6:  SN 2127 and 1737 for T and C
 
#analysis_methods:
 (i.e. how were the data processed, calibrated etc)
  - used SBE (SeaBird Electronic, Inc.) calibrations for temperature,
    conductivity and pressure sensors;
 
    dates of SBE calibrations as follows:
	(tows 1-2)
		P:(SN 50506) 23 April 1992 
                T1:(SN 1384) 28 March 1996
		T2:(SN 1008) 03 February 1996
                C1:(SN 1538) 15 September 1995
		C2:(SN 1070) 01 March 1996

	(tows 3-6)
		P:(SN 64256) 28 November 1995 
                T1:(SN 2127) 26 March 1996
                T2:(SN 2128) 26 March 1996
                C1:(SN 1737) 22 March 1996
                C2:(SN 1738) 22 March 1996


 Data Processing:
	We compute lagged correlations between temperature and 
	conductivity for each sensor pair, separately for ascending and
	descending profiles, and separately for two depth ranges: 10 to
	90 dbar, and deeper than 90 dbar, provided the segment contains  
	at least 180 scans. The fractional value of the lag at maximum 
	correlation was determined by fitting a parabola to the cross-
	correlation values. Outlying lag values (obtained occasionally 
	for data segments lasting <10 seconds or having relatively low 
	correlations between T and C) were not used in processing the data. 
	The edited values of the alignment offset were applied sequentially 
	in reprocessing the 24-Hz T/C data. To reprocess data from depths 
	shallower than 10 m, we used the value determined from the associated 
	(ascending or descending) shallowest layer. Outlying lag values 
	that were not used were replaced with local estimates of the lag 
	based on nearby values.

	To correct the 24-Hz conductivity data for the thermal mass of the
	conductivity cell, we used variable values for both the thermal
	amplitude and the thermal anomaly time constant depending on the 
	alignment offset:

	tows 1-2 (for T1-C1):
		alpha = 0.0185 + 0.0000(lag)
		tau   = 7.150  + 1.340 (lag**0.5)
			  
	tows 1-2 (for T2-C2 at end of tow 1):
		alpha = 0.0128 + 0.0000(lag)
		tau   = 7.148  + 1.329 (lag**0.5)
			  
	tows 3-6:
		alpha = 0.0127 + 0.0027(lag)
		tau   = 7.150  + 1.341 (lag**0.5)

	These variable alpha and tau values represent the optimal
	thermal mass correction based on minimizing the area in
	T-S space of selected test hours for each set of tows.
			  
	The corrected and realigned 24-Hz temperature and conductivity data are
	used to calculate 24-Hz salinity, and these are averaged to yield one-
	second averages stored in hourly files.

	Successive hourly files of the reprocessed one-second average data
	were joined to yield a single data file for each tow of the survey.
	
#instruments: 
	tow 1-2:  SBE 9/11 plus CTD SN 0258 with
	          temperature  sensors SN 1384 and SN 1008 and
	          conductivity sensors SN 1538 and SN 1070

	tow 3-6:  SBE 9/11 plus CTD SN 0428 with
	          temperature  sensors SN 2127 and SN 2128 and
	          conductivity sensors SN 1737 and SN 1738

#publications: 
#associated_datasets: CTD data from W9605A 
#associated_versions:		     *
#data_set_information:               *
#data_set_name:			     * 
#data_set_volume: 9,201 kbytes  (116,811 records)
#source_computer:  Sun Sparc 20
#source_computer_operating_system: Sun OS 4.1.3
#source_language: Fortran, C
#computer_code: ASCII
#originator_dataset_identifier: W9605A
#data_dates: 12 May - 15 May 1996 
#left_geographic_upper_bound:        126W  44N
#right_geographic_lower_bound:	     124W  42N
#geographic_region: 		     
 Northeast Pacific
#data_type: SEASOAR  data 
#sphere:                             * 
#parameters: latitude (decimal degrees), longitude (decimal degrees), pressure
 (dbars), temperature (C), salinity (psu), Sigma-t (kg/cubic meter), time
 (decimal year-day of 1996), date and time (integral year, month, day, 
 hour, minute, second), flag.
#format_description:
 (e.g. description of the header, data, record layouts. Include
 units, scales, resolution, accuracy)

 no header; each line contains:
  unfiltered GPS latitude
  unfiltered GPS longitude
  pressure (dbars), accurate to better than plus/minus 2 db
  temperature (C), accurate to plus/minus 0.01 C
  salinity (psu), accurate to plus/minus 0.01 psu
  sigma-t(kg/cubic meter),
  decimal year-day (of 1996),
  integral year, month, day, hour, minute, second 
  flag word (see format comments below for interpretation)

 The FORTRAN format for each record is:
 format(f10.5,f11.5,f6.1,3f8.4,f10.5,1x,6i2.2,1x,a4)

#format_publication: 
(a reference for any document which defines/describes the data format(s))
#format_comments: 
 (any information about the format that will be useful, but is not
 elsewhere on this form)
 
 The variable at the end of each line (the flag word) indicates
 different items:

	the ones place:  

		0 indicates use of sensor pair 1 (T1, C1)
		1 indicates use of sensor pair 2 (T2, C2)

	the tens place:
  
		0 indicates gps fix for location
		1 indicates linear interpolation between gps fixes

	the hundreds place:  

		2 indicates top or bottom of seasoar cycle
		0 indicates otherwise

	the thousands place:  

		not used
 
 The files are named tow1, tow2, ..., tow6 and all have the extension 
 of ".dat".

#misc_documentation:                *
#submittor_documentation:
 any textual information about the data, provided by the submitter,
 or investigator, (not NODC folks)  For example, in most cases this
 has been an ASCII text file accompanying the data on a DAT , diskette,
 or CDROM.  It may contain information which is redundant with other
 parts of this form.



 * leave blank

