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Tropical Atmosphere Ocean from Buoys (TAO)

Information updated on February 3, 2005, 3:19 pm GMT


General Data Description

These data files contain 2 minute average radiation and 10 minute average meteorology, precipitation, salinity and sea surface temperature data from the seven TAO buoys located on the 165E line (8n, 5n, 2n, 0n, 2s, 5s, 8s) of the TAO Buoy Array. The radiation data were obtained from TAO Array moorings through a collaborative effort between NOAA/PMEL/TAO and DOE/ARM.

Data from these buoys are stored in monthly netCDF files that are generated by PMEL.

For detailed information about sampling and sensors, see these two web pages:

sensor info
sampling infor

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Data Stream Names

Measurement Description

twp02taorad165eiiX1.a1.yyyymmdd.hhmmss.cdf

This file contains 2 minute averages of downwelling shortwave radiation in w/m**2 at 3 meters and a data quality flag.

twp10taoprecip165eiiX1.a1.yyyymmdd.hhmmss.cdf

This file contains 10 minute measurements of precipitation in mm/hr and a data quality flag.
To reduce instrumental noise, internally recorded 1-minute rain accumulation values are smoothed with a 16-minute Hanning filter upon recovery. These smoothed data are then differenced at 10-minute intervals and converted to rain rates in mm hr-1. The resultant rain rate values are centered at times coincident with other 10-minute data (0000, 0010, 0020...).

twp10taomet165eiiX1.a1.yyyymmdd.hhmmss.cdf

This file contains 10 minute averages of u and v component of the wind, and wind speed (all in m/sec), wind direction in degrees clockwise from true north, air temperature (C), sea surface temperature (C) and relative humidity (%). There are data quality flags for each of these measurements.
Winds use the oceanographic convention. A wind with zonal and meridional components of 1.0 and 1.0 is blowing toward the Northeast.

twp10taosalinity165eiiX1.a1.yyyymmdd.hhmmss.cdf

This file contains 10 minute averages of salinity (PSU) and data quality flags.

Quality Code Definitions:

0 = datum missing

1 = highest quality; Pre/post-deployment calibrations agree to within sensor specifications. In most cases only pre-deployment calibrations have been applied.

2 = default quality; Pre-deployment calibrations applied. Default value for sensors presently deployed and for sensors which were either not recovered or not calibratable when recovered.

3 = adjusted data; Pre/post calibrations differ, or original data do not agree with other data sources (e.g., other in situ data or climatology), or original data are noisy. Data have been adjusted to correct for error.

4 = lower quality; Pre/post calibrations differ, or data do not agree with other data sources (e.g., other in situ data or climatology), or data are noisy. Data could not be confidently adjusted to correct for error.

5 = sensor or tube failed

DEFINITION OF TIME:

The times within the files are stored as "true Julian day" (in the measurement named time) and milliseconds since 0:00 GMT (in the measurement named time2). The Julian day is assumed to start at 0000GMT. In order to give the netCDF files names that match other ARM names (dates as we know it), we do convert the internal start time of the file to a yyyymmdd.hhmmss date.

The "caldat" routine in IDL is used to do the time conversion. The excerpt from IDL explaining the routine states:

"The CALDAT procedure computes the month, day, year, hour, minute, or second corresponding to a given Julian date. The inverse of this procedure is JULDAY. Note The Julian calendar, established by Julius Caesar in the year 45 BCE, was corrected by Pope Gregory XIII in 1582, excising ten days from the calendar. The CALDAT procedure reflects the adjustment for dates after October 4, 1582. This routine is written in the IDL language. Its source code can be found in the file caldat.pro in the lib subdirectory of the IDL distribution."

The algorithm is more fully described here .

Temporal Coverage

The TAO Project Office provides near-real-time daily-averaged surface and subsurface data from ATLAS moorings as their standard product for climate research. Higher resolution data (which are available in these files) are recorded onboard the moorings and are made available after mooring recoveries, which are scheduled on an annual basis. Thus there may be a significant delay before data are available. Moreover, not all types of data are available for each month. The ARM XDC retrieves these data as monthly files. All available data since June 1997 are retrieved. The actual starting dates for each of the data streams are shown below.

Data StreamStart Date
twp02taorad165e0nX1.a1 01/08/1998
twp02taorad165e2nX1.a1 01/07/1998
twp02taorad165e2sX1.a1 06/15/1997
twp02taorad165e5nX1.a1 06/11/1997
twp02taorad165e5sX1.a1 01/11/1998
twp02taorad165e8nX1.a1 06/10/1997
twp02taorad165e8sX1.a1 06/17/1997
twp10taomet165e0nX1.a1 01/08/1998
twp10taomet165e2nX1.a1 02/01/1998
twp10taomet165e2sX1.a1 02/01/1998
twp10taomet165e5nX1.a1 02/01/1998
twp10taomet165e5sX1.a1 02/01/1998
twp10taomet165e8nX1.a1 02/01/1998
twp10taomet165e8sX1.a1 02/01/1998
twp10taoprecip165e0nX1.a1 01/08/1998
twp10taoprecip165e2nX1.a1 01/07/1998
twp10taoprecip165e2sX1.a1 06/15/1997
twp10taoprecip165e5nX1.a1 06/11/1997
twp10taoprecip165e5sX1.a1 01/11/1998
twp10taoprecip165e8nX1.a1 06/10/1997
twp10taoprecip165e8sX1.a1 06/17/1997
twp10taosalinity165e0nX1.a1 03/20/1999
twp10taosalinity165e2nX1.a1 03/21/1999
twp10taosalinity165e2sX1.a1 08/12/1999
twp10taosalinity165e5sX1.a1 03/14/1999

Area Covered

The area covered is the seven TAO buoys located on the 165E line (8n, 5n, 2n, 0n, 2s, 5s, 8s) of the TAO Buoy Array.

Data Stream Inputs

These data are provided by PMEL in netCDF format.

Notification Form Link

Notification form

Related Links

NOAA PMEL TAO Web site

Contacts

Data Source

Acronyms

NOAA	National Oceanic and Atmospheric Administration
PMEL	Pacific Marine Environmental Laboratory
PSU     Practical Salinity Units
TAO	Tropical Atmosphere Ocean

Citable References

"The Tropical Ocean-Global Atmosphere observing system: A decade of progress" McPhaden, M.J. et al. Journal of Geophysical Research, 103, 14,169-14,240 (1998)

"The Tropical Atmosphere Ocean (TAO) Array World Wide Web Site" Mangum, L.J. et al. Argos Newsletter, 53, 9-11 (1998)

"ATLAS Buoy -- Reengineered for the Next Decade" Milburn, H.B. et al. Proceedings of IEEE / MTS Oceans '96, 698-702 (1996)

"The Tropical Atmosphere Ocean (TAO) Array is Completed" McPhaden, M.J. Bul. of the American Meteorological Society, 76, 739-741(1995)

"TOGA-TAO Array Sampling Schemes and Sensor Evaluations" Mangum, L.J. Proceedings of the Oceans '94 OSATES, 2, 402-406 (1994) "Calibration Procedures and Instrumental Accuracy Estimates of TAO Temperature, Relative Humidity and Radiation Measurements", Freitag, H.P et al NOAA Tech. Report, (1994)