#ACCESSION NUMBER:
0125579


#CONTRIBUTOR:
Fernando Santiago-Mandujano
Data Manager
Physical Oceanographic Component of the 
Hawaii Ocean Time-series (HOT) Program

#CONTRIBUTOR INSTITUTION:
University of Hawaii
Dept. of Oceanography
1000 Pope Road
Honolulu, HI 96822
(808) 956-7000
Email: santiago@soest.hawaii.edu

#ORIGINATOR:
Dr. Roger Lukas

#ORIGINATOR INSTITUTION:
University of Hawaii
Dept. of Oceanography
1000 Pope Road
Honolulu, HI 96822
(808) 956-7896 (phone)
(808) 956-9222 (fax)
rlukas@hawaii.edu

#TITLE: 
Niskin bottle data of the Hawaii Ocean Time-series (HOT) program 
in the North Pacific 100 miles north of Oahu, Hawaii for cruises 
HOT249-258 during 2013 (NODC Accession 0125579)

#PROJECT: 
Hawaii Ocean Time-series (HOT) Program

In 1987, the National Science Foundation established a special-focus research
initiative termed 'The Global Geosciences Program'. This program is intended
to support studies of the earth as the system of interrelated physical,
chemical, and biological processes that act together to regulate the
habitability of our planet. Two of the components of the Global Geosciences
Program are the World Ocean Circulation Experiment (WOCE) and the Joint Global
Ocean Flux Study (JGOFS) programs. The former is focused on physical
oceanographic processes and the latter on biogeochemical processes.

HOT was initially funded in 1988 as a 5-year program under WOCE and 
JGOFS to make repeated observations of the physics, biology and
chemistry of the water column at a site north of Hawaii. A second 5-years of
funding were approved in 1994, 3 years more in 1998, and 3 years more in 2001.
In 2003 HOT was renewed for 5 more years, and in 2008 it was extended until
2010, and again in 2009 it was extended until 2013 (this last extension was
funded by the American Recovery and Reinvestment Act). In 2013 the project was
renewed 5 more years until 2018.

HOT is part of the ALOHA Observatory, which is being developed at HOT's 
station ALOHA.  Measurements at the HOT site contribute to the global 
description of heat, fresh water and chemical fluxes at a site 
representative of the oligotrophic North Pacific Ocean. The PO 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.

#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.  

Samples of water column chemical analyses were collected
mostly in the upper 1000m using Niskin bottles mounted on a rosette.
The strategy was to sample at density horizons within the main thermocline
at pressure horizons above and below this region (i.e., <150 dbar
and >2000 dbar).  Care was applied to ensure the highest possible
accuracy and precision.

This NODC accession contains Niskin Bottle data for HOT cruises 249-258
during 2013.  CTD and thermosalinograph data from the same cruises
are available in separate NODC accessions. Historic data for HOT
have also been archived at NODC.

#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:  21.32533
SOUTHERNMOST LATITUDE HEMISPHERE: N
NORTHERNMOST LATITUDE:  22.81083
NORTHERNMOST LATITUDE HEMISPHERE: N
WESTERNMOST LONGITUDE: 158.36484
WESTERNMOST LONGITUDE HEMISPHERE: W 
EASTERNMOST LONGITUDE: 157.89317 
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: 

2013-02-11 to 2013-12-23

#SAMPLING PERIODS:

Year    Crs#         Start & End Dates       Ship            Chief Scientist
  ------------------------------------------------------------------------
        249          11 Feb - 15 Feb 13      R/V Kilo-Moana       Curless
        250           5 Mar -  9 Mar 13      R/V Kilo-Moana       Mandujano
        251           4 Apr -  8 Apr 13      R/V Thompson         Curless
        252          16 May - 20 May 13      R/V Kilo-Moana       Updyke
        253          24 Jun - 28 Jun 13      R/V Kilo-Moana       Curless
        254          10 Sep - 14 Sep 13      R/V Kilo-Moana       Curless
        255          30 Sep -  4 Oct 13      R/V Kilo-Moana       Updyke 
        256          26 Oct - 30 Oct 13      R/V Kilo-Moana       Mandujano
        257          25 Nov - 29 Nov 13      R/V Kilo-Moana       Mandujano
        258          19 Dec - 23 Dec 13      R/V Kilo-Moana       Updyke 

#PARAMETERS: 
Bottle:
CTD Pressure (Decibars)
CTD Temperature (ITS-90)
CTD Salinity (PSU-78)
CTD Oxygen (umol/kg)
Potential Temperature (ITC-90)
Potential Density (kg/m3)
Bottle Salinity (PSS-78)
Bottle Oxygen (umol/kg)
Phosphate (PO4) (umol/kg)
Nitrate + Nitrite (NO2+NO3) (umol/kg) 
Silicate (SiO4) (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 JGOFS group and the WOCE team, 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.

Water samples are collected during HOT cruises using a 24 place
rosette. Samples of salinity, oxygen, phosphate, nitrate and
silicate are regularly taken from both shallow and deep water casts.
Salinity samples are taken back to the University of Hawaii where
they are measured using an Autosal salinometer . Phosphate, nitrate
and silicate samples are also measured at the University of Hawaii
while oxygen measurements are conducted aboard ship during the
cruises.

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).

#INSTRUMENT TYPES:
i) CTD

The underwater CTD hardware consists of a main pressure housing containing
power supplies, acquisition electronics, telemetry circuitry, and a pressure
transducer. This system has the ability to acquire various channels of data
at the rate of 24 scans per second. It has five frequency encoded channels
for two temperature, two conductivity and one pressure sensors, and eight
A/D channels for oxygen sensors, fluorometer and altimeter. The suite of
modular sensors is attached externally. The three primary sensors used
during WOCE/JGOFS work are a temperature sensor, a conductivity sensor for
measuring salinity, and a dissolved oxygen sensor. An underwater pump is
connected to the temperature sensor and conductivity cell via a tc-duct,
which then connects to the oxygen sensor to provide rapid and constant flow
of water past the sensors. The Sea-Bird 9/11 Plus system provides us with a
redundant set of temperature, conductivity and oxygen sensors connected to
another pump. In addition we have the ability to measure natural
fluorescence using a Sea-Tech Flash Fluorometer. For deep casts a Datasonics
programmable sonar altimeter (Model PSA-900) is connected to the CTD. 

ii) SeaBird Carousel
 
The SeaBird carousel is an electro-mechanical device that uses a magnetic
trigger to trip Niskin bottles upon command. This is accomplished when the
release device inside the carousel housing receives a signal from the
SeaBird deck box, which causes it to advance one position per command. This
in turn releases the lanyard for a specific Niskin bottle, assuming the
bottles were cocked beforehand.
 
iii) Niskin bottles
 
It is part of the pre-cruise preparations to log the rosette configuration
which matches Niskin bottles with rosette position. An update of this
information should be done in the Science Log if the Niskin bottles are
changed for any reason. Note that the rigging of Niskin lanyards and
inspection of Niskin bottles requires considerable experience to be done
properly.

Water samples were collected using a 24-place aluminum rosette manufactured
by Scripps Institution of Oceanography's Oceanographic Data Facility (ODF).
Twelve-liter polyvinylchloride sampling bottles, also made by ODF, were used
on this rosette. These sample bottles were equipped with Buna-N rubber
O-rings, teflon-coated steel springs and standard General Oceanics samping
valves.

#REFERENCES: 
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.

Fujieki, L.A., F. Santiago-Mandujano, C. Fumar,   
   R.  Lukas, and M. Church. Hawaii Ocean Time-series Data
   Report 24: 2012.  School of Ocean and Earth Science and Technology,
   Univ. of Hawaii, Honolulu, HI, December 2014. 394 pp.

#SUBMITTING MEDIUM:
FTP

#FILE FORMATS: 

Directories and files:
/data             root data directory
/0-data           Files as received by NODC from the originator

  /bottle         Bottle data.  Filenaming convention:

                  hotccc.sea      where ccc is cruise number

  /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


BOTTLE FORMAT:
Format for *.sea files:
-----------------------

        Welcome to the HOT Water Sample Data Base

Water sample data from HOT are written according to the *.sea
files specified by the WOCE Hydrographic Programme Office, for
submission of these data to the WHP. One file is written for
each HOT cruise (e.g., hot1.sea contains the data from HOT-1).
Files from the ALOHA-Climax (AC) cruises have the prefix ac
(e.g., ac1.sea contains the data from AC-1).

Formats for these files are detailed in the WHP Office Report
WHPO 90-1, available from Steve Diggs, WHPO Data Manager, 
Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, 
CA 92093-0214.

The files are self-explanatory, one column is written for each
measured parameter.  Missing data are filled with -9.  A 5-line
heading labels each column. 

The first year's temperatures are reported in IPTS-68.  Subsequent
temperature are reported in ITS-90 units. Since temperature
sensor calibrations were done in IPTS-68 units, and the UNESCO
routines require IPTS-68 temperature, all intermediate
processing was done in IPTS-68. As a final step, temperature and
potential temperature were converted to ITS-90 using
t_90 = 0.99976 t_68.

Variables having 7 asterisks on the 4th heading line have a quality
flag associated with them.  These 1-digit quality flags are concate-
nated to form quality word which is listed as the last variable in 
each row.  The values each digit can assume and their meanings are
listed below:

Bottle quality flag definitions:

 Byte Value  Definition
     1       Not assigned.
     2       No problems noted.
     3       Leaking.
     4       Did not trip correctly.
    5-8      Not assigned.
     9       Samples not drawn from this bottle.
 
     
Water sample quality flag definitions:    

 Byte Value  Definition
     1       Sample for this measurement was drawn from water bottle
             but analysis not received.
     2       Acceptable measurement.
     3       Questionable measurement.
     4       Bad measurement.
     5       Not reported.
     6       Mean of replicate measurements.
     7       Manual chromatographic peak integration.
     8       Irregular digital chromatographic peak integration.
     9       Sample not drawn for this measurement from this bottle.


#DATASET SIZE:
547 Kbytes

#NUMBER OF DATA UNITS:
10 unique cruises

#MISCELLANEOUS:
Previous HOT Bottle submissions to NODC:
NODC Accession                     Cruises  Years
9900208*                            1-100   1988-1998
0000639                             101-121 1999-2000
0001707                             122-154 2001-2003
0010624                             155-176 2004-2005
0041594                             177-188 2006
0048660                             189-198 2007
0055936                             199-206 2008
0069177                             208-217 2009
0087596                             218-227 2010
0101146                             228-238 2011
0119430                             239-248 2012
*includes JGOFS bio-chem parameters

Previous HOT CTD submissions to NODC:
NODC Accession                     Cruises  Years
9900206                             1-100   1988-1998
0000640                             101-121 1999-2000
0001704                             122-154 2001-2003
0010740                             155-176 2004-2005
0042029                             177-188 2006
0048725                             189-198 2007
0059482                             199-206 2008
0068957                             208-217 2009
0087584                             218-227 2010
0101727                             228-238 2011
0119895                             239-248 2012

Previous HOT thermosalinograph submissions to NODC:
NODC Accession                     Cruises  Years
9900213                             1-100   1988-1998
0000641                             101-121 1999-2000
0001710                             122-154 2001-2003
0011142                             155-176 2004-2005
0041849                             177-188 2006
0048896                             189-198 2007
0055943                             199-206 2008
0069501                             208-217 2009
0087988                             218-227 2010
0103907                             228-238 2011
0120323                             239-248 2012

Previous HOT/JGOFS Bio-Geo-Chem submissions to NODC:
NODC Accession                     Cruises  Years
0046427    *.gof                    1-198    1988-2007
0088839    *.gof                    199-227  2008-2010
0089168    *.flux, *.pp             1-227    1988-2010
