Precipitation:

The highest time resolution available is 10 minutes.
Also included in daily files are time series of 
standard deviation, and percent time raining. 
Precipitation has units of millimeters per hour and 
is measured at a height of 3.5 meters above mean 
sea level. (Instrument height is shown as a negative 
depth in data files).

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...). For further 
information see 

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.

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

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

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

In ascii format files, you will find data quality and
source codes to the right of the data. In NetCDF format 
files, you will find quality and source variables with 
the same shape as the data. These codes are defined below.

Using the quality 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