#TEMPORARY ACCESSION NUMBER:


#ACCESSION NUMBER:


#CONTRIBUTOR:
Dr. Roger Lukas

#CONTRIBUTOR INSTITUTION:
University of Hawaii
Dept. of Oceanography
1000 Pope Road
Honolulu, HI 96822

#ORIGINATOR:
same

#ORIGINATOR INSTITUTION:
same

#TITLE: 
CTD Data of the Hawaii Ocean Time-series (HOT) program in the 
North Pacific 100 Miles North of Oahu, Hawaii for Cruises 
HOT208-217 during 2009

#PROJECT: 
Hawaii Ocean Time-series (HOT)

HOT was initiated and funded through grants from the National Science
Foundation under the auspices of the Joint Global Ocean Flux Study
(JGOFS) and the World Ocean Circulation Experiment (WOCE). The
field phase of these programs has ended, but support from the Ocean
Sciences Division of NSF has enabled continuation of our basic HOT
measurement program. The physical oceanographic component contributes to
the objectives of the World Climate Research Programme (WCRP)
Climate Variability and Predictability (CLIVAR) Programme by providing
information on interannual to decadal variability of the North Pacific Ocean.
The US CLIVAR Office funded the physical oceanographic data during
2009.

#ABSTRACT:
The HOT program makes repeated observations of the physics, biology and 
chemistry at a site approximately 100 km north of Oahu, Hawaii. Two stations 
are visited about once a month: Kahe Point (Station 1:  21.34N, 158.27W) and 
Station ALOHA (Station 2: 22.75N, 158W).  Various other stations are made
intermittently in support of similar research objectives or mooring 
deployments.  

HOT CTD data are collected using a SeaBird CTD 9-11 Plus 
with dual sensors at the maximum sampling rate of 24 samples per second 
(24 Hz). They are screened for errors and processed to 2-dbar averages.  
Starting in 2006, the percent transmission field was replaced with
a nitrate in the dataset.

In separate NODC Accessions, Niskin bottle and thermosalinograph data
from these same cruises are available.

HOT 207 cruise was cut short due to a problem with the winch.  No
data are available.

#PURPOSE: 

The objective of the physical component of HOT is to describe and understand 
the ocean climate and variability at a deep-water site in the North Pacific 
subtropical gyre near Hawaii. This requires a long time series of physical 
oceanographic variables, including water mass properties and currents, 
supporting and complementing the objectives of the biogeochemical component 
of HOT.

#LOCATION EXTREMES:
SOUTHERNMOST LATITUDE:  21.34
SOUTHERNMOST LATITUDE HEMISPHERE: N
NORTHERNMOST LATITUDE:  22.75
NORTHERNMOST LATITUDE HEMISPHERE: N
WESTERNMOST LONGITUDE: 158.27
WESTERNMOST LONGITUDE HEMISPHERE: W 
EASTERNMOST LONGITUDE: 158.00 
EASTERNMOST LONGITUDE HEMISPHERE: W  

#LOCATION KEYWORDS: Hawaii, North Pacific Ocean

#SAMPLING STATIONS:

  Station     Coordinates   Approximate              Comments
                              Depth (m)

 1 (Kahe)    21 20.6'N, 158     1,500    HOT Program coastal station
             16.4'W

 2 (ALOHA)   22 45.0'N, 158     4,800    HOT Program open ocean station
             00.0'W

 3           23 25.0'N, 158     4,800    Established and ended in 1993
             00.0'W

 4           21 57.8'N, 158     4,000    Established and ended in 1993
             00.0'W

 5           21 46.6'N, 158      450     Established and ended in 1993
             00.0'W
 6 Kaena     21.85N,158.36W     2,500    Not taken on every cruise
   Point
 7 (Kauai    22 30.8'N, 158
 Basin)      10.0'W             4,800     Established in 1996
 8 (HALE     22 27.5'N, 158
 ALOHA)      7.9'W              4,800     Established in 1997

Casts have been obtained at station HALE-ALOHA during cruises
conducted for retrieval and/or re-deployment of the bottom-moored buoy.

#BEGIN AND END DATES: 

19 January 2009 - 12 December 2009

#SAMPLING PERIODS:

Year    Crs#         Start & End Dates       Ship            Chief Scientist
  ------------------------------------------------------------------------
2009    208          19 Jan - 23 Jan 09      R/V Kilo-Moana       Mandujano
        209          16 Feb - 20 Feb 09      R/V Kilo-Moana       Lethaby
        210          27 Apr -  1 May 09      R/V Knorr            Grabowski
        211/ST-15A   26 May - 30 May 09      R/V K-O-K            Mandujano
        212           2 Jul -  6 Jul 09      R/V Kilo-Moana       Curless
        213          23 Jul - 27 Jul 09      R/V Kilo-Moana       Curless
        214          17 Aug - 21 Aug 09      R/V Kilo-Moana       Lethaby
        215          23 Sep - 27 Sep 09      R/V K-O-K            Curless
        216           2 Nov -  6 Nov 09      R/V K-O-K            Lethaby
        217           8 Dec - 12 Dec 09      R/V K-O-K            Mandujano

  ------------------------------------------------------------------------

#PARAMETERS: 
CTD:
Pressure (Decibars)
Temperature (Degrees Celsius,
   International Temperature Scale of 1990)
Salinity (1978 International Practical Salinity Scale)
Oxygen (micromoles per kilogram)
Chloraphyll, Pigment (uG/L)
Nitrate (uMOL/KG)

#METHODOLOGY:

Generalities are given below.  Please see REFERENCES for additional
information.  

Each of the (approximately monthly) HOT cruises follows the same basic
pattern with some flexibility for ancillary projects to be done after the
core sampling has been completed. During transit from Honolulu to the
time-series station ALOHA (A Long-term Oligotrophic Habitat Assessment) one
weight test is done to between 700 and 1000 m at station 1 off Kahe Point
(16 km offshore from the western tip of Oahu, 21 20.6' N, 158 16.4' W,
1500 m water depth). Following the successful winch test, a CTD/rosette cast
to 1000 m is conducted. This cast serves as a "shakedown" for the remainder
of the cruise, and the functioning of the components of the CTD/rosette
system as well as coordination between winch, deck and console operators can
be tested. The training of new personnel in activities such as taking
meteorological observations, and sampling salinities is also done in this
station. The data taken at Kahe Point (station 1) represent an additional
time-series of water properties at a near-shore site.
 
Upon arrival at ALOHA (station 2), operations commence with a deep cast
(maximum depth approximately 4750 m), 36-hour burst sampling3 of the upper
1000 m at the same location, plus CTD casts to support ancillary JGOFS work
of about an extra 12 hours duration. Time permitting, the last CTD cast of
the cruise will be a deep cast. On occasion, one cast will be done at
station 3 (40 miles north of ALOHA at 23 25' N, 158 W).

The second and following casts at station ALOHA are sampled to at least 1000
m depth. Cast 2 is called a "density cast" because water samples are taken
at a number of specified density values ranging from [sigma-theta]= 27.37 to
the surface with the intent to resolve the profiles of salinity, dissolved
oxygen, and nutrients in potential density coordinates Depths sampled during 
the following casts within the 36-hour burst sampling period are chosen both 
by the science teams, who have to ensure that at least one 
water sample each is taken within the mixed layer, the shallow salinity 
maximum, the intermediate salinity minimum and the deepest position of 
the rosette for calibration of the CTD conductivity sensor. If oxygen 
bottles will be taken from the cast, then the sampling should include 
at least the mixed layer, oxygen maximum, oxygen minimum and the deepest 
rosette position for calibration of the CTD oxygen sensor. The second 
deep cast of the cruise (if there is one) should include sampling of 
oxygen bottles in at least seven levels appropriate for calibration of 
the CTD oxygen sensor, i.e. in the oxycline and two more levels below 
the oxygen minimum, in addition to the four levels mentioned before.

The primary objective of the HOT program is to assess variability in the
central Pacific Ocean on annual and interannual time scales. One of our most
important concerns, therefore, is to ensure that the highest possible
precision and accuracy is consistently maintained for all water column
chemical measurements. In order to achieve the highest possible data
quality, we have instituted a quality-assurance/quality-control program,
and have attempted to collect all ancillary information necessary to
ensure that our data are not biased by sampling artifacts.

Because sampling is over 36 hours, one can average out the effects
short-term changes of the depth of density surfaces and the magnitude of
hydrographic and nutrient variables (inertial, tidal, and shorter periods).

CTD data were acquired at a rate of 24 samples per second. Digital 
data were stored on a laptop personal computer and, for redundancy, the 
analog signal was recorded on VHS videotapes. Backups of CTD data were 
made onto Zip disks and later onto compact disks. The raw CTD data were 
quality controlled and screened for spikes as described in Winn et al. 
(1993).  Data alignment, averaging, correction and reporting were done 
as described in Tupas et al.  (1993). Salinity spike rejection parameters 
were modified for some cruises in 2004 because of rough sea conditions. 
Spikes occur when the CTD samples the disturbed water of its wake;
therefore, samples from the downcast are rejected when the CTD is moving
upward or when its acceleration exceeds 0.5 m s-2 in magnitude. Cruises 155, 
156, and 157 were conducted under 19 relatively rough conditions. The CTD 
acceleration cutoff value had to be increased to between 0.55 and 0.65 m s-2 
for some of the casts to relax the data rejection criteria and avoid 
eliminating an excessive number of points.  The data were additionally 
screened by comparing the temperature and conductivity sensor pairs. These 
differences permitted identification of problems in the sensors. Only the 
data from one set of T-C sensors and one oxygen sensor, whichever was 
deemed most reliable, is reported here.

#INSTRUMENT TYPES:

Sea-Bird CTD SBE-9/llPlus

Continuous measurements of temperature, salinity, oxygen and 
fluorescence are made with a Sea-Bird SBE-9/11Plus CTD package 
with dual temperature, salinity and oxygen sensors and fluorometer 
described in Fujieki (2004). CTD underwater unit No.91361
was used during 2006.

Starting HOT-177 (2006), the Transmissometer (XMISS) data that was
once included in the CTD files have been replaced by continuous Nitrate
measured using Satlantic's InSitu Underwater Spectrometer (ISUS V2).
Satlantic's ISUS V2 is a chemical free sensor that uses UV absorption
technology to provide accurate nitrate concentration measurements in
real-time.

Temperature is reported in the ITS-90 scale. Salinity and all derived 
units were calculated using the UNESCO (1981) routines; salinity is 
reported in the practical salinity scale (PSS-78).  Oxygen is reported in 
µmol kg-1 and Chloropigment (Fluorescence) in µg/l.
 
#REFERENCES
1990 Chiswell, S., E. Firing, D. Karl, R.  Lukas and C. Winn. Hawaii
   Ocean Time-series Program Data Report 1, 1988-1989. SOEST Tech. Rept.
   1, School of Ocean and Earth Science and Technology, Univ. of Hawaii,
   Honolulu, HI, 269 pp.
                                                                                       
2007 Fujieki, L.A., F. Santiago-Mandujano, P. Lethaby, 
   R.  Lukas, and D. Karl. Hawaii Ocean Time-series Program Data
   Report 19, 2007.  School of Ocean and Earth Science and Technology,
   Univ. of Hawaii, Honolulu, HI, June 2010. 403 pp.

#SUBMITTING MEDIUM:
FTP

#FILE FORMATS: 

Directories and files:
/data             root data directory
/0-data           Files as received by NODC from the originator
  /woce_sum       WOCE-type sum file which gives details on
                  position and parameters taken of each cast and
                  station of each cruise.  Filenaming convention:

                  hotccc.sum      where ccc is cruise number

  /ctd            CTD data.  Filenaming convention:

                  hcccasstt.ctd   where ccc is cruise number
                                        a   is constant
                                        ss  is station number
                                        tt  is cast number

CTD Data Format Document, January 13, 1992

    CTD data are distributed in a format specified by the international
WOCE Hydrographic Programme Office (WHPO).  This document describes 
that format.

    Each station/cast is stored in a separate file.  A file's name can be
determined by the concatenation of 'h', 2 digit cruise number, 'a', a 2 digit
station number, a 2 digit cast number and a file extension of ctd.  For ex-
ample, HOT-1, station 2, cast 3, would be found in h01a0203.ctd.

    The cruise and position information for each cast is in the cruise
summary file (*.sum).  The EXPOCODE, station number and cast number
can be used to cross-reference the CTD data files with the cruise
summary file.  This code allows for the identification of the cruise.
It consists of a 4 character NODC country-ship code, a maximum of 8
character cruise number followed by a "/" and leg number.  For example,
the EXPOCODE for HOT-13 on the R/V Moana Wave would be 31MW013/1.

    The CTD data file has a fixed record length of 65 characters / record. 
The first six records of a CTD file contain header information:

    Record 1:
       Column  Format	Item
         9-22     a14   EXPOCODE (KA=Kaimalino,WE=Wecoma,MW=Moana Wave)
        31-34     a4    WHP station identification
        41-42     i2	Month
        43-44     i2	Day
        45-46     i2	Year
        FORTRAN FORMAT  (8x,a14,8x,a4,6x,3i2)
        C               "%*s %s %*s %s %*s %2d%2d%2d"

    Record 2:
         7-12     a6	Station number
        20-22     i3	Cast number
        36-40     i5	Number of data records in the file
        FORTRAN FORMAT  (6x,a6,7x,i3,13x,i5)
        C               "%*s %d %*s %d %*s %d"

    Record 3:
        16-21     i6    Instrument number
        37-41    f5.2	Sampling rate (hz)
        FORTRAN FORMAT  (15x,i6,15x,f5.2)
        C               "%*s %d %*s %f"

    Record 4:
        Headers for data columns (variable labels).
        
    Record 5:
        Unit header for data columns.
        
    Record 6:
        Quality byte designators.  All columns requiring a quality
        byte are underscored by seven asterisks.
                

     The remaining records contain CTD data. The order of variables in a
record are as follows: pressure, temperature, salinity, oxygen, nitrate,
fluorescence and quality.  Missing values are flagged with -99.0.

   Data Record Format:

        Column	Format	Item
	 1-8	f8.1 	Pressure (Decibars)
	 9-16	f8.4 	Temperature (Degrees Celsius,
                           International Temperature Scale of 1990)
	17-25	f9.4	Salinity (1978 International Practical Salinity Scale)
	26-33	f8.1	Oxygen (micromoles per kilogram)
        34-41   f8.3    Nitrate (micro Moles per Kilogram)
	42-49   f8.3    CHLPIG (uG/L)
	50-57    i8     Number of observations averaged at this pressure level
	58-65	 i8     Quality (defined by investigator) **
	FORTRAN FORMAT  (f8.1, f8.4, f9.4, f8.1, 2f8.3, i8, i8)
	C               "%f %f %f %f %f %f %d %d"


**  The quality word is the left-to-right concatenation of required qualityi
 bytes for the variables measured.  They are defined as follows:

 byte value  Definition
     1       Not calibrated with water samples.
     2       Acceptable measurement.
     3       Questionable measurement.
     4       Bad measurement.
     5       Not reported.
     6       Interpolated value.
     7       Not assigned for CTD data
     8       Not assigned for CTD data
     9       Not sampled

#DATASET SIZE:
8,544 kbytes; 214 files

#NUMBER OF DATA UNITS:
10 unique cruises

#MISCELLANEOUS:
Previous HOTs Bottle submissions to NODC:
NODC Accession                 Contents
9900208                        HOTs 1988-1998
0000639                        HOTs 1999-2000
0001707                        HOTs 2001-2003
0010624                        HOTs 2004-2005
0041594                        HOTs 2006
0048660                        HOTs 2007
0055936                        HOTs 2008

Previous HOTs CTD submissions to NODC:
NODC Accession                 Contents
9900206                        HOTs 1988-1998
0000640                        HOTs 1999-2000
0001704                        HOTs 2001-2003
0010740                        HOTs 2004-2005
0042029                        HOTs 2006
0048725                        HOTs 2007
0059842                        HOTs 2008

Previous HOTs thermosalinograph submissions to NODC:
NODC Accession                 Contents
9900213                        HOTs 1988-1998
0000641                        HOTs 1999-2000
0001710                        HOTs 2001-2003
0011142                        HOTs 2004-2005
0041849                        HOTs 2006
0048896                        HOTs 2007
0055943                        HOTs 2008
