NODC DOCUMENTATION FOR CTD DATASETS #documentation_file_name: t0205.csr.txt #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: * #submitter_email: omalley@coas.oregonstate.edu #collection_information: (i.e cruise dates, ports, cast numbers, time of cast, longitude and latitude of casts) Thomas G. Thompson cruise T0205 31 May to 17 June, 2002 Newport, Oregon to Newport, Oregon Seasoar sampling in 8 tows as follows: Tow no. Start date,time End date,time Parameters measured (2002) (UT) (2002) (UT) 1 01 Jun 2254 02 Jun 1817 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 2 03 Jun 0259 06 Jun 0344 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 3 06 Jun 2134 07 Jun 1901 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 4 08 Jun 1513 09 Jun 1930 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 5 10 Jun 1510 11 Jun 0402 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 6 12 Jun 1444 13 Jun 1654 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 7 13 Jun 2010 15 Jun 0841 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 8 16 Jun 0742 17 Jun 1539 P, T1, C1, T2, C2, PAR, FL1, FL2, FL3 Tows 1 - 3 composed the mesoscale-1 mapping survey, and were bounded to the north by 44.7 degrees N, to the south by 41.8 degrees N, to the west by 125.8 degrees W, and to the east by 124.1 degrees W. Tows 4 - 5 covered a finescale mapping survey to the north, bounded to the north by 44.7 degrees N, to the south by 43.7 degrees N, to the west by 125.2 degrees W, and to the east by 124.1 degree W. Tows 6 - 7 was a finescale survey to the south, bounded to the north by 43.3 degrees N, to the south by 41.8 degrees N, to the west by 125.5 degrees W, and to the east by 124.3 degrees W. Tow8 was the second mesoscale mapping (meso2), bounded to the north by 44.7 degrees N, to the south by 43.2 degrees N, to the west by 125.3 degrees W, and to the east by 124.1 degrees W. Maximum sampling depth of 225 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: * #pi_email: barth@coas.oregonstate.edu #project: The GLOBEC NEP Mesoscale Surveys #funding agency: NSF #grant/contract-no: OCE-0001035 #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 from the T-C pair indicated below; final data were from the following pairs of sensors: tow 1 preferred sensor pair: 1,2 tow 2 preferred sensor pair: 1 tow 3 preferred sensor pair: 1 tow 4 preferred sensor pair: 1 tow 5 preferred sensor pair: 1 tow 6 preferred sensor pair: 2 tow 7 preferred sensor pair: 2,1 tow 8 preferred sensor pair: 2,1 for tow 1 - 8: preferred sensor pair 1: SN 2127 and 1737 for T and C preferred sensor pair 2: SN 2128 and 1738 for T and C #analysis_methods: (i.e. how were the data processed, calibrated etc) Calibrations from SeaBird Electronic, Inc. (SBE) were used for the temperature, conductivity and pressure sensors. for tow 1: Dates of SBE CTD #428 calibrations as follows: P:(SN 64256) 28 March 2001 T1:(SN 2127) 26 March 2002 T2:(SN 2128) 26 March 2002 C1:(SN 1737) 26 March 2002 C2:(SN 1738) 26 March 2002 for tow 2-12: Dates of SBE CTD #258 calibrations as follows: P:(SN 50506) 10 February 1999 T1:(SN 2127) 26 March 2002 T2:(SN 2128) 26 March 2002 C1:(SN 1737) 26 March 2002 C2:(SN 1738) 26 March 2002 Data Processing: We compute lagged correlations between the temperature and conductivity time series for each sensor pair. In order to calculate the correlation between T and C, we work with the first-differences of those time series. We then find the maximum cross correlation, along with the values on each side of it, and fit a parabola to those three points. The maximum of the parabola gives the fractional scan offset to be used in shifting the conductivity time series to match up with the temperature time series. This is done for every up- and down- trace profile of seasoar data. The time series of up-trace lags and the time series of down-trace lags were then individualy cleaned by statistical methods. Each lag value is examined with its time series to see if it falls within three standard deviations of the mean of a centered, 101-point window. Those outside three sigma of the mean are then replaced with the window's average value, in an iterative process. To correct the 24-Hz conductivity data for the thermal mass of the conductivity cell, we allowed both the amplitude (alpha) and time constant (tau) of the thermal mass correction to be functions of the lag between T and C. These variable alpha and tau values can be obtained by minimizing the area in T-S space of selected test hours for each tow. These values then represent the optimal thermal mass correction for each tow. If the data were too noisy, or the tow too short, then the thermal mass values optimizations from the closest useful tow were used. Using the above method, the thermal mass variable alpha and tau can be calculated as functions of lag as: alpha = alpha.slope * lag + alpha.offset tau = tau.slope * lag**0.5 + tau.offset the slopes and offsets can be summarized for each tow as follows: sensor [--- alpha ---] [--- tau ---] tow pair slope offset slope offset 1 1 0.000000 0.01516 1.340 7.149 1 2 0.012552 0.00285 1.316 7.132 2 1 0.000000 0.01354 1.339 7.150 3 1 0.000009 0.01529 1.337 7.144 4 1 0.000000 0.01572 1.340 7.150 5 1 0.000000 0.01476 1.344 7.150 6 2 0.007712 0.00822 1.344 7.155 7 2 0.004097 0.00968 1.339 7.158 7 1 0.001292 0.00535 1.337 7.163 8 2 0.003343 0.01323 1.343 7.153 8 1 0.000345 0.00864 1.347 7.152 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. Three fluorometers were used on this survey; two from WetStar and one from SeaPoint. The SeaPoint fluorometer was tuned to detect fluoroscein tracers, and the two WetStar fluorometers were set from Chl and CDOM detection. Converting the 0-5 volt output of the chl fluorometer to chlorophyll-a was be done with the following calibration equations: Chla (ug/L) = 18.9316*Fl(V) - 4.3217 Successive hourly files of the reprocessed one-second average data were joined to yield a single data file for each tow of the survey. The single file for each tow was then broken into the different component lines. #instruments: tow 1: SBE 9/11 plus CTD SN 0428 with: SBE pressure sensor SN 64256 SBE temperature sensors SN 2127 and SN 2128 and SBE conductivity sensors SN 1737 and SN 1738 tow 2-12: SBE 9/11 plus CTD SN 0258 with: SBE pressure sensor SN 50506 SBE temperature sensors SN 2327 and SN 2329 and SBE conductivity sensors SN 1896 and SN 1898 #publications: * "SeaSoar Observation During the GLOBEC NEP California Current Survey III (T0205) 31 May - 17 June 2002" by R. O'Malley et al., Data Report 196, Reference 2004-4, December 2004 #associated_datasets: CTD data from T0205 #associated_versions: * #data_set_information: * #data_set_name: * #data_set_volume: 111,083 kbytes (894,547 records) #source_computer: Sun Sparc Ultra 10 #source_computer_operating_system: Sun OS 5.6 #source_language: Fortran, C #computer_code: ASCII #originator_dataset_identifier: T0205 #data_dates: 01 June - 17 June 2002 #left_geographic_upper_bound: 126W 45N #right_geographic_lower_bound: 124W 41N #geographic_region: Northeast Pacific #data_type: SEASOAR data #sphere: * #parameters: col 1: latitude (decimal degrees) col 2: longitude (decimal degrees) col 3: pressure (dbars) col 4: temperature (C) col 5: salinity (psu) col 6: Sigma-t (kg/cubic meter) col 7: potential temperature (C) col 8: sigma-theta (kg/cubic meter) col 9: time (decimal year-day of 2000) col 10: date and time (integral year, month, day, hour, minute, second) col 11: flag col 12: PAR (0-5 volts) col 13: FL1 (Chl) (volts) col 14: FL2 (CDOM) (volts) col 15: FL3 (flscn) (volts) col 16: chlorophyl-a (micro g/liter) #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), potential temperature (C), sigmat-theta (kg/cubic meter), decimal year-day (of 2000), integral year, month, day, hour, minute, second flag word (see format comments below for interpretation) PAR (volts), accurate to 0.001 volts fluorescence (Chl) (volts), accurate to 0.001 fluorescence (CDOM) (volts), accurate to 0.001 fluorescence (flscn) (volts), accurate to 0.001 (green filter) chlorophyll-a (micro g/liter), accurate to 0.01 The FORTRAN format for each record is: format (f10.5,f11.5,f6.1,5f8.4,f10.5,1x,6i2.2,1x,i4.4,4f6.3,f6.2) "no data" values are indicated by 9-filling: temperature, salinity, sigma-t, potential temerature, or sigma-theta all use 99.9999 to indicate "no data" present for that record; voltages uses 9.999 to indicate "no data" chlorophyll uses 999.99 to indicat "no data" #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: 1 indicates collection of water sample from the 5-m intake 0 indicates otherwise The files all have the extension of ".dat2c". All data are identified by their maps (meso1,north,south,meso2) and are separated into their E-W lines (line1 through line12 overall, with intermediate lines indicate by line1a (between line1 and line2, etc) or are identified as connecting lines (eg: north.line2a_3.dat2c goes from the end of line2a to the start of line3 for the north map). Partial coverage of a line is incremented alphabeticly (eg: south.line9.a.dat2c and south.line9.b.dat2c). Repeat coverage of the same line on the same map is given a decimal number (eg: line9.1 and line9.2) (none on this survey). #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