
Surface Meteorological Data:

Surface met data are delivered in these files as a package 
for the period after 1989 when relative humidity first 
became available. Sea surface temperature, air temperature, 
and winds are available before 1989 at several sites, and since 
1980 at 0,110W. Winds use the oceanographic convention. A wind 
with zonal and meridional components of 1.0 and 1.0 is blowing 
toward the Northeast. Daily averaged wind speeds and directions
are based on daily averaged wind velocity components. Wind speed 
and wind components are in units of meters per second, direction 
is in degrees clockwise from true north, air temperature and sea 
surface temperature are in degrees centigrade, and relative 
humidity is in percent.

ATLAS buoys used in TAO and PIRATA measure meteorological and 
oceanographic data at the following heights and depths relative 
to mean sea level

     Winds: 4.0 meters height
     Relative Humidity: 3.0 meters height
     Air Temperature: 3.0 meters height
     Sea Surface Temperature: 1.0 meters depth

TRITON buoys replaced ATLAS buoys in the Pacific west of
160E beginning in 1999.  TRITON buoys measure meteorological
and oceanographic data at the following heights and depths
relative to mean sea level

     Winds: 3.5 meters height
     Relative Humidity: 2.2 meters height
     Air Temperature: 2.2 meters height
     Sea Surface Temperature: 1.5 meters depth

In ascii files organized by site, these depth and height
differences are explicitly distinguished. In files containing
both ATLAS and TRITON data, ATLAS heights and depths are used.
(Note that instrument heights are shown as negative depths 
in data files).

The study by Freitag et al ("Calibration procedures and instrumental 
accuracies for ATLAS wind measurements", NOAA. Tech. Memo. OAR 
PMEL-119, 2001) discovered a systematic error in standard and 
NextGeneration ATLAS wind directions of approximately 6.8 degrees 
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

  http://www.pmel.noaa.gov/tao/proj_over/vane_correct.html.

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 degrees (of which 6.8 degrees is a bias) 
while expected RMS error for NextGeneration ATLAS wind directions is 
about +/- 5 degrees with no appreciable bias.

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

   http://www.pmel.noaa.gov/tao/proj_over/sensors.shtml

   http://www.pmel.noaa.gov/tao/proj_over/sampling.html

For detailed information about the TAO array, see

McPhaden, M.J., A.J. Busalacchi, R. Cheney, J.R. Donguy,
K.S. Gage, D. Halpern, M. Ji, P. Julian, G. Meyers,
G.T. Mitchum, P.P. Niiler, J. Picaut, R.W. Reynolds,
N. Smith, K. Takeuchi, 1998: The Tropical Ocean-Global
Atmosphere (TOGA) observing system: A decade of
progress. J. Geophys. Res., 103, 14,169-14,240.
   http://www.pmel.noaa.gov/pubs/outstand/mcph1720/abstract.shtml

For general information about PIRATA, see

Servain, J., A.J. Busalacchi, M.J. McPhaden, A.D. Moura,
G. Reverdin, M. Vianna, and S.E. Zebiak, 1998: A Pilot
Research Moored Array in the Tropical Atlantic (PIRATA).
Bull. Am. Meteorol. Soc., 79, 2019-2031.

For information about the TAO/TRITON collaboration see
   http://www.pmel.noaa.gov/tao/proj_over/triton.html

If you selected daily data at 8n137e or 6s10w, you may
get more than one file per site. This is because the 
original deployments for these sites were at 7n137e and
5s10w, respectively, while present deployments are at 
8n136e and 6s10w. The file names will clearly indicate
which site the data come from. For more details about 
mooring locations, you can deliver daily average position 
data for most deployments under the data category of 
"Buoy Positions" on the delivery page.

If you selected high resolution data, you may find that 
you have several files, each with a different averaging
interval, for example, hourly, 15 minute, and 10 minute.
In addition, if you selected the site at 0n110w, you may
get data in separate files from several groups of deployments 
clustered around 0n110w since mooring locations have been 
in significantly different locations at different times.
The file names will clearly indicate the site locations.

In ascii format files, to the right of the data, you will 
find data quality codes for wind speed and direction, air
temperature, sea surface temperature and relative humidity. 
In 10-minute ascii files, you will also find source codes. 
Quality and source codes are defined below.

Similarly, in netcdf files you will find variables of
quality and source codes, with the same shape as the data.

Using these codes you can tune your analysis to trade-off 
between quality and temporal/spatial coverage. 


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 in an attempt to
reduce the 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

Source code definitions:

    0 - No Sensor, No Data 
    1 - Real Time (Telemetered Mode)
    2 - Derived from Real Time
    3 - Temporally Interpolated from Real Time
    4 - Source Code Inactive at Present
    5 - Recovered from Instrument RAM (Delayed Mode)
    6 - Derived from RAM
    7 - Temporally Interpolated from RAM

Dates and times are specified in ascii files as
two integers such as

   19920131 2350

which means 1992 January 31 at 11:50 pm GMT. High resolution
files may also specify seconds with two additional digits
on the 2nd integer, such as 235000.

Your data files will be deleted from our server at 
midnight Pacific time.

You can access your files using this relative web address,
i.e., you must insert the server name, which is most likely
www.pmel.noaa.gov:
/cache-tao/st1/deliv/data30779

If you use the data in publications, please acknowledge the TAO Project
Office, Dr. Michael J. McPhaden, Director.  Also, we would appreciate
receiving a preprint and/or reprint of those publications utilizing
the data for inclusion in the TAO Project bibliography.  Relevant
publications should be sent to:

The TAO Project Office
NOAA/Pacific Marine Environmental Laboratory
7600 Sand Point Way NE
Seattle, WA 98115

Please send comments, questions, or problems to "atlasrt@noaa.gov".

