TAO Refresh
Mooring Sensors
The TAO Refreshed System transitioned to a commercial off the shelf sensor and a satellite system (Iridium), already proven within NDBC's coastal and offshore weather and oceanographic buoy systems, that will allow the Array to meet requirements for hourly resolution time series data and high-frequency weather phenomena. The new data collection and communications systems will provide in real-time the comprehensive data that was normally only-available once the sensors are recovered every 12 months. The most cost-effective approach for sensor replacement was to use sensors time-tested and proven in the Triangle Trans-Ocean Buoy Network (TRITON) Array developed and operated by the Japan Marine Science and Technology Center (JAMSTEC).
Sensor | PMEL TAO Legacy | JAMSTEC TRITON | NDBC TAO Refresh |
Wind Sensor | RM Young 05103 | RM Young 05103 w/ WHOI 7050-A | RM Young 05103 |
Compass | EG&G 63764 or KVH LP101-5 | N/A | Sparton SP3003D |
Air Temperature/Relative Humidity | Rotronic MP-101A | Rotronic MP-101A w/ WHOI 7030-A | Rotronic MP-101A |
Sea Surface Temperature/Sea Surface Conductivity | PMEL ATLAS Module | Seabird SBE 37-IM MicroCAT | Seabird SBE 37-SM MicroCAT |
Sea Temperature/Pressure | PMEL ATLAS Module | Seabird SBE 37-IM MicroCAT | Seabird SBE 39-IM |
Point Source Current Speed and Direction | SonTek Argonaut-MD | SonTek Argonaut-MD | SonTek Argonaut-MD |
Short Wave Solar Radiation | Eppley PSP-TAO w/ PMEL Interface | Eppley PSP w/ WHOI 7070-A | Eppley PSP w/ PSI Interface |
Long Wave Solar Radiation | Eppley PIR-TAO w/ PMEL Interface | N/A | Eppley PIR /w PSI Interface |
Rain Gauge | RM Young 50203-34 w/ PMEL Interface | Scientific Technology ORG-115 | RM Young 50203-34 |
Barometer | Paroscientific MET 1-2 | Paroscientific MET 1-485 | Paroscientific MET1 |
The instrumental accuracies listed below are based on pre-deployment calibrations. The post deployment calibrations and the root mean square drift of a group of sensors is still being determined for Refresh Ocean Temperature Sensors (SBE39). Manufacture and initial tests indicate the drift to be small. The Wind sensors, Air Temperature\Relative Humidity (AT\RH) sensor, Sea Surface Temperature\Conductivity (SSC) sensors, Long Wave Radiations (LWR), and Short Wave Radiation sensor (SWR) and Point Source Current Sensors are the same sensors used on the TAO Legacy buoys. Determinations of instrumental accuracies conducted by PMEL are used for Refresh. The accuracies listed are based on pre-deployment and post-recovery calibrations and are the root mean square drift of a group of sensors.
Measurement | Sensor Type | Manufacture/Model | Resolution | Range | Accuracy | Notes |
Wind Speed | Propeller | RM Young/05103 | 0.2 m s-1 | 0 to 35 m s-1 | 0.3 m s-1 or 3% | 8 |
Wind Direction | Vane | RM Young/05103 | 1.4 ° | 0 to 359 ° | 5 ° | 8 |
Air Temperature | Pt100 RTD | Rotronics/MP101A | 0.01 °C | -40 to +60 °C | 0.2 °C | 8 |
Relative Humidity | Hygromer C94 | Rotronics/MP101A | 0.4% | 0 to 100% | 2% | 8 |
Precipitation | Capacitance | RM Young/50203 | 0.2 mm | 0 to 50 mm | 1 mm | 3,4,10 |
Downwelling Shortwave Radiation | Pyranometer | Eppley Laboratory/PSP | 0.4 W m-2 | 0 to 1600 W m-2 | ±1% | 3 |
Downwelling Longwave Radiation | Pyranometer | Eppley Laboratory/PIR | 0.1 W m-2 | 0 to 500 W m-2 | ±1% | 3,4 |
Surface Air Pressure | Pressure Transducer | Paroscientific/MET1-2 | 0.1 hPa | 800 to 1100 hPa | 0.1 hPa or 0.01% | 3 |
Sea Surface Temperature | Thermistor | Seabird/SBE 37 | 0.001 °C | -5 to +35 °C | 0.01 °C | 5,8 |
Salinity | Internal field conductivity cell | Seabird/SBE 37 | 0.00001 S m-1 | 0 to 7 S m-1 | 0.02 psu | 1,8,9 |
Temperature (Ocean) | Thermistor | Seabird/SBE 39IM | 0.001 °C | -5 to +35 °C | 0.01 °C | 5,6 |
Pressure (hydrostatic) | Strain element within silicon diaphragm | Seabird/SBE 39IM (Druck sensor) | 0.002% full scale | 0 to 600 dBar | 0.1% full scale | 7 |
Ocean Current Speed | Doppler Current Meter | SonTek/Argonaut MD | 0.1 cm s-1 | 0 to 600 cm s-1 | 5 cm s-1 | 2 |
Ocean Current Direction | Doppler Current Meter | SonTek/Argonaut MD | 0.1 ° | 0 to 359 ° | ±5 ° | 2 |
Compass Heading | 3-axis, tilt-compensated digital compass | Spartan 3000 | 0.1 ° | 0 to 359 ° | 0.8 ° | |
Notes:
1 Surface salinity measured at all sites. Subsurface capability available at selected sites at depths 10, 20, 40, 60, 80 or 10, 25, 75, 100, 125 m.
2 For point velocity measurements, current meters shall be placed at 1 to 5 depths in the upper 200 m with at least one within 10 m of the surface. Current should be measured at all flux reference sites and at other selected sites.
3 At flux reference sites only.
4 Required only if an outside agency provides longwave radiation and rain sensors.
5 SBE 37 Micro CAT and SBE 39’s thermistor accuracy and stability (typical drift is less than 0.002 °C per year).
6 Subsurface temperature available at 10 depths on mooring.
7 The SBE 39’s optional pressure sensor, developed by Druck, Inc., Compensation of the temperature influence on pressure offset and scale is performed by the SBE 39’s CPU.
8 Sensor in use on Legacy ATLAS moorings.
9 Salinity is computed from measurements of temperature, pressure, and conductivity using the Practical Salinity Scale (PSS-78) and therefore salinity error is a function of the errors in the measurement of temperature, pressure and conductivity. For NDBC TAO Refresh, conductivity and temperature are measured on TAO refresh buoys near the ocean surface and salinity is computed using an assumed pressure at nominal depth, with pressure error assumed to be zero. Conductivity and temperature accuracies are as stated for the SBE-37 Conductivity-Depth Sensor. In computing salinity using PSS-78, temperature must first be converted to temperatures based on the International Practical Temperature Scale (IPTS-68) on which the PSS-78 is based. The TAO Refresh Conductivity-Temperature sensor measures temperature in the International Temperature Scale (ITS-90) and is reported in ITS-90. In computing salinity, temperature is converted from the ITS-90 to IPTS-68 prior to the salinity computation.
10 Accuracy to be determined.
NextGeneration ATLAS
Mooring Sensors
The table below identifies the types of sensors
used on NextGeneration ATLAS moorings and lists their accuracies. Most
instrumental accuracies listed are based on
pre-deployment and post-recovery calibrations and are
the root mean square drift of a group of sensors.
Mechanical current meters and current profilers
accuracies are based on intercomparisons between
co-located instruments. References where available
are indicated by [#] in the comments column and
listed at the end of the tables. Accuracies of
sensors which are new to ATLAS moorings (longwave
radiation, barometric pressure) or which have not yet
been evaluated (water pressure) are those
specified by the manufacturer and are indicated by
[M].
In cases where sensors are paired with PMEL
supplied electronics (e.g., analog to digital boards)
calibrations include both the sensor and PMEL
electronics. Accuracies listed here (with the
exception of currents) do not include environmental
factors such as wind (on rainfall) or buoy motion (on
radiation). Measurement ranges listed are generally
those over which the sensors are calibrated. The
ranges over which a sensor will operate (determined
by the sensor and/or PMEL electronics) are listed in
parenthesis if they significantly exceed the
calibration range.
The array is presently maintained with
NextGeneration ATLAS moorings, sensors for which are
shown in the top (blue shaded) table. Sensor
specifications for standard ATLAS and early current
meter moorings (both of which are no longer in use)
are shown in the bottom table.
A comparison of ATLAS, TRITON, and Improved
METeorological (IMET) mooring meteorological sensors
from a land-based intercomparison study at the Woods
Hole Oceanographic Institution in May-June 2000 shows
that in general the three systems measure to
equivalent standards of accuracy. The full report of
this intercomparison is contained in footnote [13]
below.
Measurement |
Sensor
type |
Manufacturer:
Model # |
Resolution |
Range |
Accuracy |
Comments |
Wind
speed |
Propeller |
R. M. Young:
05103 |
0.2 m
s-1 |
1-20 m s-1
(0.4 - 36 m
s-1)
|
±0.3 m
s-1 or 3% |
[7] |
Wind direction |
Vane |
R. M. Young:
05103 |
1.4° |
0-355° |
5° - 7.8° |
[7]
See also footnote to
[7] |
Fluxgate
compass |
E.G.and G. or
KVH: 63764 or LP101-5 |
1.4° |
0-359° |
Air
temperature |
Pt-100 RTD
(Resistance Temperature Recorder) |
Rotronic Instrument Corp.:
MP-100 |
0.01°C
|
14-32°C
(0-40°C)
|
±0.2°C |
[12] |
Relative
humidity |
Capacitance |
0.4 %RH
realtime
0.02 %RH delay mode |
55-95 %RH
(0-100 %RH)
|
±2.7
%RH |
[12] |
Rainfall |
Capacitance |
R. M. Young:
50203-34 |
0.2 mm
hr-1 |
0-50
mm |
±0.4 mm
hr-1 on 10 min filtered
data |
[6] |
Downwelling
shortwave radiation
|
Pyranometer |
Eppley
Laboratory: PSP-TAO, Delrin case |
0.4 W
m-2 |
200-1000 W
m-2
(0-1600 W
m-2)
|
±1% |
[M] Evaluation
underway |
Downwelling
longwave radiation |
Pyrgeometer |
Eppley
Laboratory: PIR-TAO, Delrin case, 3-output
(1) |
0.1 W m-2
0.03°C
|
200 W m-2
@ 20°C (thermopile
only)
|
±1% |
[M] Nominal
calibration values used for case and dome
thermistors |
Barometric
pressure |
Pressure
transducer |
Paroscientific:
MET1-2 |
0.1
hPa |
800-1100
hPa |
±0.01%
of reading |
[M] |
Sea surface
and subsurface temperature |
Thermistor |
PMEL: NX ATLAS
using YSI (Yellow Springs Instruments)
thermistor 46006 |
0.001°C |
6-32°C
(0-40°C)
|
±0.02°C |
[9]
Evaluation of accuracy underway |
Sea surface
and subsurface temperature |
Thermistor |
Sea Bird
Electronics: SBE16, SBE37 |
0.001°C |
1-31°C
(-5-35°C)
|
±0.003°C |
[3] |
Salinity |
Internal field conductivity
cell |
Sea
Bird Electronics: SBE16 (Seacat) |
0.0001 S m-1 |
3-6 S m-1
(0-6 S
m-1)
|
±0.02 psu |
[3]
Based on SBE16 only. SBE37 assumed
comparable.
Accuracy of ATLAS module under
evaluation |
SBE37
(Microcat) |
0.00001 S
m-1 |
Sea Bird cell
with ATLAS module |
0.002 S
m-1 |
Water
pressure |
Transducer |
Paine:
211-30-660-01 |
0.03
psi |
400-800 psi
(0-1000 psi)
|
±0.25%
full scale (1000psi) |
[M] |
Ocean current
(profile) |
Acoustic
Doppler Current Profiler |
RD Instruments:
Narrow band, 150 kHz |
0.1 cm s-1
0.006
|
(0-256 cm
s-1) |
±5 cm
s-1,
±2.5°
|
[5]
[11] |
Ocean
current (single
point) |
Dopper Current
Meter |
SonTek:
Argonaut |
0.1 cm s-1
0.1°
|
(0-600 cm
s-1) |
±5 cm
s-1,
±5°
|
[10] |
Standard ATLAS and Early
Current Meter Mooring Sensors
Measurement |
Sensor
type |
Manufacturer:
Model # |
Resolution |
Range |
Accuracy |
Comments |
Wind
speed |
Propeller |
R. M. Young:
05103 |
0.2 m
s-1 |
1-20 m s-1
(0.4 - 36 m
s-1)
|
±0.3 m
s-1 or 3% |
[7] |
Wind direction |
Vane |
R. M. Young:
05103 |
1.4° |
0-355° |
5° - 7.8° |
[7]
See also footnote to
[7] |
Fluxgate compass |
E.G.and G. or KVH: 63764 or
LP101-5 |
1.4° |
0-359° |
Air
temperature |
Pt-100 RTD
(Resistance Temperature Detector) |
Rotronic Instrument Corp.:
MP-100 |
0.04°C
|
14-32°C
(0-40°C)
|
±0.2°C |
[2] |
Relative
humidity |
Capacitance |
0.4 %RH
realtime
0.02 %RH delay mode |
55-95 %RH
(0-100 %RH)
|
±2.7
%RH |
[2] |
Downwelling
shortwave radiation
(Current Meter Moorings) |
Pyranometer |
Eppley
Laboratory: PSP |
1.3 W
m-2 |
700 W m-2
(0-1600 W
m-2)
|
±2% |
[2] |
Sea surface
temperature |
Thermistor |
PMEL: Standard
ATLAS SST sensor using YSI (Yellow Springs
Instruments) thermistor 46006 |
0.001°C |
14-32°C |
±0.03°C |
[2] |
Sea surface
temperature |
Thermistor |
PMEL: Current
meter mooring SST sensor using YSI thermistor
46006 |
0.001°C |
14-32°C |
±0.01°C |
[2] |
Subsurface
temperature |
Thermistor
|
PMEL: Standard
ATLAS sensor using YSI thermistor 46006
|
0.001°C |
6-32°C
(2-35°C)
|
±0.09°C |
[2] |
Subsurface
temperature |
Thermistor |
PMEL: Mini
Temperature Recorder (MTR) using YSI thermistor
46006 |
0.001°C |
6-29°C
(-2-34°C)
|
±0.01°C |
Accuracy based
on unpublished PMEL calibrations |
Subsurface
temperature |
Thermistor |
EG&G
VACM |
0.001°C |
1-31°C |
±0.05°C |
[8]
|
Subsurface
temperature |
Thermistor |
EG&G
VMCM |
0.006°C |
1-31°C |
±0.05°C |
[8] |
Subsurface
temperature |
Thermistor |
Sea Data TR-2,
TDR-2 |
0.01°C |
1-31°C
(-5-35°C)
|
±0.05°C |
[8]
|
Sea surface
and subsurface temperature |
Thermistor |
Sea Bird
Electronics: SBE16, SBE37 |
0.001°C |
1-31°C
(-5-35°C)
|
±0.003°C |
[3] |
Salinity |
Internal field
conductivity cell |
Sea Bird
Electronics: SBE16 (Seacat) |
0.0001 S
m-1 |
3-6 S m-1
(0-6 S
m-1)
|
±0.02
psu |
[3] |
Water
pressure |
Transducer |
Paine:
211-30-660-01 |
0.03
psi |
400-800 psi
(0-1000 psi)
|
±0.25%
full scale (1000psi) |
[M] |
Ocean
current (single
point) |
Savonious rotor
and vane |
EG&G
VACM |
0.005 cm
s-1
2.8°
|
(2-300 cm
s-1) |
±3-7 cm
s-1,
±5.6°
|
[4] |
Ocean
current
(single point)
|
Orthogonal
Propellers |
EG&G
VMCM |
0.01 cm s-1
1.4°
|
(0.9 - 340 cm
s-1) |
±3-7 cm
s-1,
±2.5°
|
[4]
|
Ocean current
(profile) |
Acoustic
Doppler Current Profiler |
RD Instruments:
Narrow band, 150 kHz |
0.1 cm s-1
0.006
|
(0-256 cm
s-1) |
±5 cm
s-1,
±2.5°
|
[5] |
References:
[1] Fairall, C. W., P. O. G. Persson, E.F.
Bradley, R. E. Payne and S. P. Anderson, 1998: A new
look at calibration and use of Eppley Precision
Radiometers. Part I: Theory and Application. J.
Atmos. Ocean. Tech., 15, 1229-1242.
[2]
Freitag, H.P., Y. Feng, L.J. Mangum, M.P. McPhaden,
J. Neander, and L.D. Stratton, 1994: Calibration
procedures and instrumental accuracy estimates of TAO
temperature, relative humidity and radiation
measurements. NOAA Tech. Memo. ERL PMEL-104,
32 pp.
[3]
Freitag, H.P., M.E. McCarty, C. Nosse, R. Lukas, M.J.
McPhaden, and M.F. Cronin, 1999: COARE Seacat data:
Calibrations and quality control procedures. NOAA
Tech. Memo. ERL PMEL-115, 89 pp.
[4] Halpern, D., 1987: Comparison of upper
ocean VACM and VMCM observations in the equatorial
Pacific. J. Atmos. Ocean. Tech., 4,
84-93.
[5] Plimpton, P.E., H.P. Freitag, and M.J.
McPhaden, 1995: Correcting moored ADCP data for
fish-bias errors at 0°,110°W and
0°,140°W from 1990 to 1993. NOAA Tech.
Memo. ERL PMEL-107, 49 pp.
[6]
Serra, Y.L., P.A'Hearn, H.P. Freitag, and M.J.
McPhaden, 2001: ATLAS self-siphoning rain gauge error
estimates. J. Atmos. Ocean. Tech.,18,
1989-2002.
[7]
Freitag, H.P., M. O'Haleck, G.C. Thomas, and M.J.
McPhaden, 2001: Calibration procedures and
instrumental accuracies for ATLAS wind measurements.
NOAA. Tech. Memo. OAR PMEL-119, NOAA/Pacific Marine
Environmental Laboratory, Seattle, Washington, 20
pp.
Footnote: This study
discovered a systematic error in standard and
NextGeneration ATLAS wind directions of
approximately 6.8° in the counterclockwise
direction. This error was present possibly as
far back as 1984. Modifications were made to
the NextGeneration ATLAS system in 2000 to
correct this error in subsequent deployments,
and archived NextGeneration ATLAS wind
directions were corrected (both daily averages
and high resolution datasets) on 28 March 2002.
See Corrected
NextGeneration Atlas Wind Directions. .
Standard ATLAS wind directions have not been
corrected in the archives since the exact time
when the error began to affect the measurements
is unknown. Standard ATLAS were used
exclusively between 1984 and 1996 when
NextGeneration ATLAS moorings began to replace
them. By November 2001, the standard ATLAS had
been phased out and the array was comprised
entirely of NextGeneration systems. Expected
RMS error for standard ATLAS wind direction is
7.8° (of which 6.8° is a bias) while
expected RMS error for NextGeneration ATLAS
wind directions is about ±5° with no appreciable
bias. |
[8] McCarty, M.E., and M.J. McPhaden, 1993:
Mean seasonal cycles and interannual variations at 0,
165E during 1986-1992. NOAA Tech. Memo. ERL PMEL-98,
64pp.
[9] A'Hearn,
P.N., H.P. Freitag, and M.J. McPhaden, 2002: ATLAS
module temperature bias due to solar heating. NOAA
Tech. Memo OAR PMEL-121, NOAA/Pacific Marine
Environmental Laboratory, Seattle, WA, 24
pp.
[10]
Freitag, H.P., M.J. McPhaden, C.Meinig, and
P.Plimpton, 2003: Mooring motion bias of point
Doppler current meter measurements. In: Proceedings
of the IEEE Seventh Working Conference on Current
Measurement Technology, San Diego, CA, 13-15 March
2003, IEEE, Piscataway, NJ, 155-160.
[11]
Plimpton, P.E., H.P. Freitag, and M.J. McPhaden,
2004: Processing of subsurface ADCP data in the
equatorial Pacific. NOAA Tech. Memo OAR PMEL-125,
NOAA/Pacific Marine Environmental Laboratory,
Seattle, WA. 41pp.
[12]
Lake, B.J., S.M. Noor, H.P. Freitag, and M.J.
McPhaden, 2003: Calibration procedures and
instrumental accuracy estimates of ATLAS air
temperature and relative humidity measurements. NOAA
Tech. Memo. OAR PMEL-123, NOAA/Pacific Marine
Environmental Laboratory, Seattle, WA, 23
pp.
[13]
Payne, R.E., K. Huang, R.A. Weller, H.P. Freitag,
M.F. Cronin, M.J. McPhaden, C. Meinig, Y. Kuroda, N.
Ushijima, R.M. Reynolds, 2002: A comparison of buoy
meteorological systems. WHOI Technical Report
WHOI-2002-10. Woods Hole Oceanographic Institution,
67 pp.
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