Mooring Information
TAO REFRESH MOORINGS
The Tropical Atmosphere Ocean (TAO) Array has transitioned from the National Oceanic and Atmospheric Administration's (NOAA) research arm (Pacific Marine Environmental Laboratory, PMEL) to its operational arm within the National Weather Service at the National Data Buoy Center (NDBC). NDBC's transition strategy had two motives: First, to maintain continuity of the existing observations for the climate record and, second (but equally as important) to ensure its future contributions and survival which will be accomplished by a comprehensive equipment upgrade, known as the TAO Technology Refresh (TAO Refresh). TAO Refresh was always an important component of NDBC's transition of the Array. Presently, the Array uses the NextGeneration Autonomous Temperature Line Acquisition System (ATLAS) mooring system, designed in the 1990s and the deployments completed in 2001, now termed TAO Legacy.
|
|
As part of a comprehensive test plan to ensure continuity of the climate records, NDBC conducted laboratory tests and several prototype TAO Refresh systems deployed in the Gulf of Mexico and the Pacific TAO array. Currently eight (8) TAO Refreshed buoys are deployed in the Pacific for in-situ testing with TAO Legacy. The intention is to reduce to 5 TAO Refreshed buoys for extended testing. Initial evaluations indicate good agreement between TAO Legacy and TAO Refresh. These refresh buoys are deployed adjacent to legacy buoys, which are considered a co-located buoy. The refresh buoy data will be available via the Global Telecommunication System (GTS) under the SXPA01 KWNB header in World Meteorological Organization (WMO) FM-18 BUOY alphanumeric formats. The Refreshed buoy is designed to meet requirements for National Weather Service, climate research, and international Global Ocean Observing System (GOOS, http://www.ioc-goos.org/) and Global Climate Observing System (GCOS, http://www.wmo.int/pages/prog/gcos/) purposes while increasing the real-time data available for climate analysis, forecasts, and numerical model predictions.
|
|
The WMO station index numbers for the Refresh buoys are as of 25 June 2010:
|
WMO ID | LOCATION |
51350 | 0N140W |
52112 | 2S165E |
51365 | 2S170W |
51348 | 5N140W |
51352 | 5S140W |
51366 | 5S170W |
51353 | 8N155W |
52114 | 8S165E |
|
LEGACY ATLAS
MOORINGS
|
Design of the relatively inexpensive ATLAS
(Autonomous Temperature Line Acquisition System)
mooring was initiated by PMEL's Engineering
Development Division (EDD) in 1984 (see Standard ATLAS Moorings, below).
By the mid-1990's, a reengineering effort was
underway to modernize the ATLAS mooring with emphasis
on:
- improving data quality
- adding new sensors
- increasing temporal resolution of
internally recorded data
- improving reliability to extend system
life
- simplifing fabrication
procedures
- reducing costs
|
This effort used as many of the components
and procedures of the existing system as possible,
thereby minimizing the impact on the infrastructure
that supported the array.The first Generation
systems were deployed in the array in May 1996. The
transition to the NextGeneration ATLAS throughout the
array was completed in November 2001.
|
A significant NextGeneration ATLAS
improvement over the Standard ATLAS is the
incorporation of inductively coupled sensors for
subsurface data. The sensors clamp onto the wire rope
strength member that serves as one of the inductive
elements. This simplifies fabrication, eliminating the
themistor cable with its labor-intensive assembly and
deployment procedures. Addressable modules on the cable
allow the system to be expanded for new sensors by
adding the appropriate hardware and software
interfaces. |
|
Flexibility in the design also allows the
interface of additional sensors including rainfall,
short-wave and long-wave radiation, barometric
pressure, ocean salinity and currents. Most
measurements are made at a sample rate of 10 minutes,
with the exception of barometric pressure (1 hour),
short-wave and long-wave radiation (2 minutes), and
rainfall (1 minute). These high temporal resolution
data are recorded internally and available after
mooring recovery as delayed mode data. |
HISTORICAL STANDARD ATLAS
MOORINGS
|
After
testing and deployment of prototype ATLAS moorings, the
first elements of the large scale monitoring TAO array
were deployed in the eastern Pacific in November 1984.
The full TAO array was eventually completed in December
1994. The standard ATLAS mooring had a design lifetime
of one year and the system proved to be robust and
reliable. Over 500 Standard ATLAS moorings were
deployed between 1984 and 2001. The final standard
ATLAS was recovered in November 2001 and the NextGeneration
ATLAS moorings are now used exclusively in the TAO
array. |
Standard ATLAS moorings measured surface
winds, air temperature, relative humidity, sea
surface temperature, and ten subsurface temperatures
from a 500 m long thermistor cable. Daily-mean data
were telemetered to shore in near real-time via
NOAA's polar-oribiting satellites and Service Argos.
A small subset of hourly values (2-3 per day)
coinciding with satellite passes were also
transmitted in real time. Hourly values of surface
data were internally recorded and available after
mooring recovery.
|
CURRENT METER MOORINGS
|
Subsurface
Acoustic Doppler Current Profiler (ADCP) moorings are
deployed at a few equatorial sites (0-147E, 0-165E,
0-170W, 0-140W and 0-110W). These data are available
only after the subsurface moorings are recovered. On
nearby ATLAS moorings at 0-165E, 0-140W and 0-110W,
upper ocean currents are also measured at 4 to 5
discrete depths in the upper 300 m using point Doppler
current meters. Real-time telemetry of these currents
is under development. |
In the
past, older style current meter moorings have been
deployed at a few equatorial sites (0-156E, 0-165E,
0-140W and 0-110W). Upper ocean currents were measured
at 4 to 7 discrete depths in the upper 300 m using
vector-averaging mechanical current meters. In general,
these moorings differed from ATLAS moorings in that no
subsurface data were telemetered in real time and in
that subsurface data were internally recorded at higher
sample rates than Standard ATLAS systems. Between 1990
and 1995, current meter moorings were referred to as
PROTEUS (PRofile TElemetry of Upper ocean currentS)
moorings and included downward looking ADCP mounted in
the surface toroidal float. PROTEUS mooring deployments
stopped in 1995 because fish backscatter interfered
with the acoustic signals and seriously contaminated
the velocity measurements. |
TAO
SURFACE MOORING HARDWARE
The TAO surface buoy is a 2.3 m diameter
fiberglass-over-foam toroid, with an aluminum tower and
a stainless steel bridle. When completely rigged, the
system has an air weight of approximately 660 kg, a net
buoyancy of nearly 2300 kg, and an overall height of
4.9 m. The electronics tube is approximately 1.5 m
long, 0.18 m diameter, and weighs 27 kg. The buoy can
be seen on radar from 4-8 miles depending on sea
conditions.
|
|
Non-rotating 3/8" (0.92 cm) diameter wire
rope jacketed to 1/2" (1.27 cm) is used in the upper
700 meters to guard against damage from fish bite.
Standard ATLAS thermistor cables are fixed to the
mooring wire with wire rope clamps. Plaited 8-strand
3/4" (1.9 cm) diameter nylon line is used for the
remainder of the mooring. Anchors are fabricated from
scrap railroad wheels, and typically weight 1900-2000
kg. All hardware is standard equipment as used in
other PMEL taut-line moorings and deployments follow
the traditional anchor last routine.
|
Moorings are deployed in water depths
between 1500 and 6000m. To ensure that the upper
section of the mooring is nearly vertical a nominal
scope of 0.985 (ratio of mooring length to water
depth) is employed on the moorings in water depths of
1800m or more. At a few sites, slack moorings with
scope 1.35 have been deployed due to either shallow
bathymetry or severe current regimes. In these cases,
the upper portion of the mooring is keep fairly
vertical (but less so than taut-line moorings) by
using a reverse catenary design.
|
NOMINAL HEIGHTS AND DEPTHS OF TAO
SENSORS
Standard instrument heights for TAO
sites: LWR is Long Wave Radiation sensor,
SWR is Short Wave Radiation sensor,
Rain is rain gauge, ATRH is
air/relative humidity sensor, BP is Barometric
Pressure sensor
All TAO sites |
Wind
|
LWR
|
SWR
|
Rain
|
ATRH
|
BP
|
Height (m) |
4 m
|
3.5 m
|
3.5 m
|
3.5 m
|
3 m
|
3 m
|
Standard instrument depths for TAO
sites are listed below: SST is Sea Surface
Temperature sensor. SSC is Sea Surface
Conductiviy and temperature. T1, T2, ...., T10
are subsurface thermistors. TP9 and
TP10 are subsurface temperature and pressure
sensors. TC1,...,TC6 are subsurface
temperature and conductivity sensors.
Pacific
Ocean |
SST
|
T1 |
T2 |
T3 |
T4 |
T5 |
T6 |
T7 |
T8 |
TP9 |
TP10 |
Depths (m) east of
155°W
|
1
|
20 |
40 |
60 |
80 |
100 |
120 |
140 |
180 |
300 |
500 |
Depths (m) at and west of
155°W
|
1
|
25 |
50 |
75 |
100 |
125 |
150 |
200 |
250 |
300 |
500 |
Atlantic Ocean |
SSC
|
TC1
|
TC2
|
T3
|
T4
|
T5
|
TC6
|
T7
|
T8
|
TP9
|
TP10
|
Depths (m), all sites |
1 |
20 |
40 |
60 |
80 |
100 |
120 |
140 |
180 |
300 |
500 |
Instrument depths for older current-meter
sites on the equator at 156°E, 165°E,
140°W, 110°W were different from the above,
and varied over time. Present NextGeneration ATLAS
moorings at current meter sites measure temperatures
at the standard depths above, plus a few additional
depths. For graphical info on instrument depths, see
the TAO data
availability page. In NetCDF files used for web
displays, temperatures have been regridded to the
above standard depths.
|
TRITON
MOORINGS
In October 1999, responsibility for moorings
along and to the west of 156E was assumed by the Japan
Agency for Marine-Earth Science and Technology
(JAMSTEC) which has deployed Triangle Trans-Ocean Buoy
Network (TRITON) buoys at those locations. Data from
both ATLAS and TRITON moorings are merged in a common
data base and available from both PMEL and
JAMSTEC. |
|