#ACCESSION NUMBER:
0098789

#CONTRIBUTOR:
Fernando Santiago-Mandujano
Contact Information:
Work: 808 956 7000
mandujan@soest.hawaii.edu

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

#ORIGINATOR:
Dr. Roger Lukas
Contact Information:
Work: 808 956 4101
Fax: +1 808 956 9222
rlukas@hawaii.edu

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

#TITLE: 
Next generation vector averaging current meter data 
from the WHOI Hawaii Ocean Timeseries Site (WHOTS) program
in the North Pacific from 2004 to 2011

#PROJECT: 
The Woods Hole Oceanographic Institution (WHOI)
Hawaii Ocean Timeseries (HOT) Site (WHOTS)

Data available free of charge. User assumes all risk for use of data. 
User must display CITATION in any publication or product using data.

CITATION: "These data were collected and made freely available by 
Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries 
(HOT) Site (WHOTS), supported by the National Oceanic and Atmospheric 
Administration (NOAA) through the Cooperative Institute for Climate 
and Ocean Research (CICOR) under Grant No. NA17RJ1223 to the Woods 
Hole Oceanographic Institution, and via a subcontract from the UH NSF
project OCE03-27513."

#ABSTRACT:
The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries 
(HOT) Site (WHOTS) is a coordinated part of HOT, and consists of a mooring
that has been providing measurements of high-quality air-sea fluxes and the
associated upper ocean response at Station ALOHA, about 100 km north of Oahu,
Hawaii since August 2004. WHOTS is funded by NOAA and NSF and it is led by the
WHOI Upper Ocean Processes Group.

The WHOTS mooring is located at station ALOHA (a 6 nautical mile radius circle
centered at 22 45'N, 158 W) in the central subtropical gyre of the North
Pacific. The mooring has been in place for one-year periods since 2004 at a
location that has been alternating between the eastern and southern edges of
ALOHA.

This NODC accession contains Next Generation Vector Averaging Current Meter
(NGVM) measurements at 10 and 30 m depths for the first 7 WHOTS deployments
(2004-2011).  The northward and eastward current components are provided 
within NetCDF files (OceanSITES time-series Conventions 1.2).

NODC accession 0090188 holds temperature and conductivity (salinity) data
collected using SeaBird SBE-16 SeaCAT and SBE-37 MicroCAT instruments
for the first 7 WHOTS deployments (2004-2011).  Additional data for currents
from ADCPs will be provided for WHOTS deployments 1-7.

#PURPOSE: 
In 2003, Robert Weller (Woods Hole Oceanographic Institution [WHOI]), Albert
Plueddemann (WHOI) and Roger Lukas (University of Hawaii [UH]) proposed to
establish a long-term surface mooring at the Hawaii Ocean Time-series (HOT)
Station ALOHA (22 45N, 158W) to provide sustained, high-quality air-sea
fluxes and the associated upper ocean response as a coordinated part of the
HOT program, and as an element in the National Oceanic and Atmospheric
Administration’s (NOAA) array of global ocean reference stations.

With support from the NOAA and the National Science Foundation (NSF), the WHOI
HOT Site (WHOTS) surface mooring has been maintained at Station ALOHA since
August 2004. The objective of this project is to provide long-term,
high-quality air-sea fluxes as a coordinated part of the HOT program and
contribute to the goals of observing heat, fresh water and chemical fluxes at
a site representative of the oligotrophic North Pacific Ocean. The approach is
to maintain a surface mooring outfitted for meteorological and oceanographic
measurements at a site near Station ALOHA by successive mooring turnarounds.
These observations will be used to investigate air sea interaction processes
related to climate variability.

#LOCATION EXTREMES:
SOUTHERNMOST LATITUDE:  22.670167
SOUTHERNMOST LATITUDE HEMISPHERE: N
NORTHERNMOST LATITUDE:  22.766667
NORTHERNMOST LATITUDE HEMISPHERE: N
WESTERNMOST LONGITUDE: 157.95
WESTERNMOST LONGITUDE HEMISPHERE: W 
EASTERNMOST LONGITUDE: 157.89833
EASTERNMOST LONGITUDE HEMISPHERE: W  

#LOCATION KEYWORDS: 
North Pacific Ocean, Hawaii, Station ALOHA

#SAMPLING STATIONS:
The WHOTS mooring is located at station ALOHA (a 6 nautical mile radius circle
centered at 22 45'N, 158 W) in the central subtropical gyre of the North
Pacific. The mooring has been in place for one-year periods since 2004 at a
location that has been alternating between the eastern and southern edges of
ALOHA (22 46.00'N, 157 53.90'W (Station 50), and 22 40.21'N, 157 57.00'W
(Station 52) respectively).

#BEGIN AND END DATES: 
13 August 2004 - 11 July 2011

#SAMPLING PERIODS:
Deploy- Deployment-Recovery       Station Coordinates
ment       Date        Date       Number 
Number 
------- ---------------------------- --- ----------------------
WHOTS-1	12 August, 2004-25 July, 2005 50 22 46.00'N 157 53.90'W
WHOTS-2	28 July, 2005-26 June, 2006   50 22 46.00'N 157 53.91'W
WHOTS-3	26 June, 2006-28 June, 2007   50 22 45.99'N 157 53.99'W
WHOTS-4	25 June, 2007-6 June, 2008    52 22 40.21'N 157 57.00'W
WHOTS-5	5 June, 2008-16 July, 2009    50 22 46.01'N 157 53.83'W
WHOTS-6	10 July, 2009-3 August, 2010  52 22 39.91'N 157 56.66'W
WHOTS-7	27 July, 2010-11 July, 2011   50 22 39.91'N 157 56.66'W

Specifics for NGVM time series
Columns
1: WHn, where n is WHOTS deployment number
2: depth of current meter in meters
3: date of start
4: time of start (GMT)
5: date of end
6: time of end (GMT)

 1       2        3        4           5          6
WH1_NGVM_10  2004-08-13 03:41:00Z  2005-04-18 05:15:00Z
WH1_NGVM_30  2004-08-13 03:41:00Z  2005-07-25 17:14:00Z
WH2_NGVM_10  2005-07-28 03:42:00Z  2006-06-24 18:29:60Z
WH2_NGVM_30  2005-07-28 03:42:00Z  2006-06-24 18:29:60Z
WH3_NGVM_10  2006-06-27 01:47:00Z  2007-06-28 15:18:60Z
WH3_NGVM_30  2006-06-27 01:47:00Z  2007-06-28 15:18:60Z
WH4_NGVM_10  2007-06-26 01:50:00Z  2008-04-07 01:52:60Z
WH4_NGVM_30  2007-06-26 01:50:00Z  2008-06-06 17:17:60Z
WH5_NGVM_10  2008-06-05 04:25:00Z  2009-03-06 18:35:00Z
WH5_NGVM_30  2008-06-05 04:25:00Z  2009-04-16 18:20:00Z
WH6_NGVM_10  2009-07-11 02:21:00Z  2010-04-07 21:09:00Z
WH6_NGVM_30  2009-07-11 02:21:00Z  2010-08-02 17:08:60Z
WH7_NGVM_10  2010-07-29 04:01:00Z  2011-07-11 16:28:00Z
WH7_NGVM_30  2010-07-29 04:01:00Z  2011-07-11 16:28:00Z
*note series length truncated for some instruments such
as WH1 at 10m.

#PARAMETERS: 
northward and eastward current components

#METHODOLOGY:
NGVM data from the WHOTS deployments were processed at the University
of Hawaii.  The records were truncated to 2 hours after deployment 
allowing time for mooring motions associated with the sinking anchor 
to die out. Velocity data from the NGVM at 30 m was compared with the 
ADCP data from the equivalent depth cell.  Complete details of
post-deployment processing is summarized (Mandujano et. al., 2008).
Data were replaced by an interpolated value if a data point exceeded 
four times the standard deviation of the deployment mean.

Velocity differences between the NGVM and the ADCP were compared with wave
data from the Datawell directional buoy located approximately 5 miles 
offshore of Waimea Bay on the north of O’ahu.  A burst sampling scheme was 
utilized for the WHOTS-1 deployment in order to resolve orbital motions
due to large swell. However, the subsequent deployment, WHOTS-2, did not
utilize a burst sampling scheme and any influence due to swell might be 
reflected in a larger disparity with the NGVM data. Velocity differences 
greater than 0.1 m s-1 were identified, but do not seem to correlate with 
episodes of large swell for either deployment. We conclude that orbital 
wave motions from large swell do not adversely affect the velocity data 
and that there appears to be no bias from the different sampling schemes 
used for the two deployments.

#INSTRUMENT TYPES:
Next Generation Vector Averaging Current Meter (NGVM) 

#REFERENCES
Fernando Santiago-Mandujano, Paul Lethaby, Roger Lukas, Jefrey Snyder
Robert Weller, Albert Plueddemann, Jeffrey Lord, Sean Whelan, Paul Bouchard,
and Nan Galbraith, Hydrographic Observations at the Woods Hole Oceanographic 
Institution (WHOI) Hawaii Ocean Timeseries (HOT) Site (WHOTS): 2004 - 2006,
Data Report No. 1. School of Ocean and Earth Science and Technology, 
University of Hawaii, Honolulu, 2008. pp 229. 
http://www.soest.hawaii.edu/whots/docs/Whots_data_report_1.pdf

#SUBMITTING MEDIUM:
FTP

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

File Naming Convention and Format

filename: WHn_NGVM_dd.nc

where n: WHOTS deployment number
     dd: depth (meters) of current meter
    .nc: denotes NetCDF file 
         Conventions = OceanSITES 1.2
         Netcdf_version = 4.0.1 
         naming_authority = OceanSITES

/1-data           Files created by NODC

filename: WHn_NGVM_dd_metadata.txt where n and dd are defined above
content: these text files contain metadata associated with each
         NetCDF file created using NetCDF function ncdump.

#DATASET SIZE:
105,584 mbytes

#NUMBER OF DATA UNITS:
7 unique mooring deployments

#MISCELLANEOUS:
NODC accession 0090188 holds temperature and conductivity (salinity) data
collected using SeaBird SBE-16 SeaCAT and SBE-37 MicroCAT instruments
for the first 7 WHOTS deployments (2004-2011).
