the highest vertical resolution and most rigorously
quality-controlled profiles available. The quality
control of the data occurs in two stages; the DACs
perform initial screenings and three Regional
Quality Control centres perform a more rigorous
scientific quality control. All these centres coordinate the collection and monitor data receipts to
ensure maximum data recovery to the WOCE Data
Resource.
Sea level
WOCE in-situ sea-level data are received from a
global network of tide gauges and the data are
treated in two different modes. The fast delivery
DAC obtains data in real time from over 100
stations globally and provides hourly, daily and
monthly data sets within a month of collection.
The delayed-mode centre assembles and quality
controls data from 160 stations, and provides
original resolution and hourly data, station metadata, summary statistics as well as plots of
low-frequency variations, and analysis of tidal
constants.
Floats
Prior to WOCE there was no mechanism to assemble or archive data from neutrally buoyant floats.
The WOCE DAC first assembled historical float
data and made this available on CD-ROM. The
WOCE float data are assembled by the WOCE
subsurface float DAC in Woods Hole. Visual
images of float tracks are made available as a
regular product.
Moored measurements
Moored current meter arrays have been deployed
for WOCE in narrow passages and in regions of
strong currents. The data set consists of velocity,
time and position for each current meter, and may
also include temperature, salinity and pressure.
The Current Meter DAC has generated mean flow
statistics for each array, and has acquired and
quality controlled a large set of relevant historical data. The QC system and product generation capabilities developed by the DAC provide
unprecedented ability for PIs to generate data
reports.
Surface meteorology/air–sea flux
During the WOCE observation period research
vessels and moored buoys collected high-frequency
marine meteorology data including surface winds,
air and sea temperature, humidity, atmospheric
pressure, precipitation and other variables. The
Surface Meteorology DAC assembles, extensively
quality controls and documents these data. Air–sea
flux values for momentum, turbulent heat and
moisture can be estimated from the data using
bulk formulae. The Air–Sea Fluxes SAC is one of a
number of groups that produce near-global fields
of atmospheric variables and fluxes as well as
uncertainties.
Surface salinity
Surface salinity data from bottle samples and from
thermosalinographs are assembled by IFREMER
in France.
Satellite measurements
Satellite altimetry data have been collected from
the ERS-1, ERS-2 and TOPEX/POSEIDON platforms, providing unprecedented observations of
sea level variability and wave height. Also of interest to WOCE are measurements of wind velocity
from scatterometers, as well as Sea Surface Temperature (SST) and water vapour content from
radiometers. The satellite agencies distribute data
and a variety of gridded fields and other products
from their online data centres. The global products resulting from ocean observation from low
earth orbit provide unprecedented information
for the analysis and synthesis of sparse in-situ
measurements.
Bathymetry
Bathymetric data from WOCE survey vessels are
assembled and archived by the National Geophysical Data Center (NGDC) in the USA. Here they
are merged into the central database of depth
information about the ocean. Data from WOCE
are separately recoverable from NGDC.
Acoustic Doppler current profiler
Direct current measurements are made by ADCPs
operated as hull-mounted instruments sampling
the upper 300 m and as lowered ADCPs sampling the full water column at stations. The ADCP
DAC at present assembles the shipboard data and
can provide the full resolution data set and an
averaged set with hourly time spans and 10 m
depth intervals. The DPC is working to ensure
lowered ADCP data will become a part of the final
SECTION 3 NEW WAYS OF OBSERVING THE OCEAN
188
quality-controlled profiles available. The quality
control of the data occurs in two stages; the DACs
perform initial screenings and three Regional
Quality Control centres perform a more rigorous
scientific quality control. All these centres coordinate the collection and monitor data receipts to
ensure maximum data recovery to the WOCE Data
Resource.
Sea level
WOCE in-situ sea-level data are received from a
global network of tide gauges and the data are
treated in two different modes. The fast delivery
DAC obtains data in real time from over 100
stations globally and provides hourly, daily and
monthly data sets within a month of collection.
The delayed-mode centre assembles and quality
controls data from 160 stations, and provides
original resolution and hourly data, station metadata, summary statistics as well as plots of
low-frequency variations, and analysis of tidal
constants.
Floats
Prior to WOCE there was no mechanism to assemble or archive data from neutrally buoyant floats.
The WOCE DAC first assembled historical float
data and made this available on CD-ROM. The
WOCE float data are assembled by the WOCE
subsurface float DAC in Woods Hole. Visual
images of float tracks are made available as a
regular product.
Moored measurements
Moored current meter arrays have been deployed
for WOCE in narrow passages and in regions of
strong currents. The data set consists of velocity,
time and position for each current meter, and may
also include temperature, salinity and pressure.
The Current Meter DAC has generated mean flow
statistics for each array, and has acquired and
quality controlled a large set of relevant historical data. The QC system and product generation capabilities developed by the DAC provide
unprecedented ability for PIs to generate data
reports.
Surface meteorology/air–sea flux
During the WOCE observation period research
vessels and moored buoys collected high-frequency
marine meteorology data including surface winds,
air and sea temperature, humidity, atmospheric
pressure, precipitation and other variables. The
Surface Meteorology DAC assembles, extensively
quality controls and documents these data. Air–sea
flux values for momentum, turbulent heat and
moisture can be estimated from the data using
bulk formulae. The Air–Sea Fluxes SAC is one of a
number of groups that produce near-global fields
of atmospheric variables and fluxes as well as
uncertainties.
Surface salinity
Surface salinity data from bottle samples and from
thermosalinographs are assembled by IFREMER
in France.
Satellite measurements
Satellite altimetry data have been collected from
the ERS-1, ERS-2 and TOPEX/POSEIDON platforms, providing unprecedented observations of
sea level variability and wave height. Also of interest to WOCE are measurements of wind velocity
from scatterometers, as well as Sea Surface Temperature (SST) and water vapour content from
radiometers. The satellite agencies distribute data
and a variety of gridded fields and other products
from their online data centres. The global products resulting from ocean observation from low
earth orbit provide unprecedented information
for the analysis and synthesis of sparse in-situ
measurements.
Bathymetry
Bathymetric data from WOCE survey vessels are
assembled and archived by the National Geophysical Data Center (NGDC) in the USA. Here they
are merged into the central database of depth
information about the ocean. Data from WOCE
are separately recoverable from NGDC.
Acoustic Doppler current profiler
Direct current measurements are made by ADCPs
operated as hull-mounted instruments sampling
the upper 300 m and as lowered ADCPs sampling the full water column at stations. The ADCP
DAC at present assembles the shipboard data and
can provide the full resolution data set and an
averaged set with hourly time spans and 10 m
depth intervals. The DPC is working to ensure
lowered ADCP data will become a part of the final
SECTION 3 NEW WAYS OF OBSERVING THE OCEAN
188