TWP/SMET/C3 - Intermittent Pressure Sensor Failure

The Barometric Pressure sensor was intermittently failing at TWP site C3 Darwin.  At times 
there were large pressure fluctuations occurring on the order of 24 mb in a few minutes. 
 Times of large pressure fluctuations are readily apparent in the data.  At these times 
the data should be carefully analyzed before determining it's usefulness.  In between the 
periods of large fluctuations the readings appear to be stable.  It is still suggested 
that independent pressure data be obtained for comparison before use.

• Barometric Pressure(atmos_pressure)

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Rain blocked pressure port

Atmospheric pressure values were suspect due to anomolous readings during heavy rain 
events.  Suspect blockage of port due to rainfall.  New logger and enclosure corrected problem.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Negative rainfall rates

Due to limitations of the Zeno dataloggers all voltage measurements
from the optical rain gauge (ORG) were converted to rainfall rates. 
This resulted in negative values for rain rates.  Any value below
0.10 mm/hr should be considered to be 0 mm/hr.  New dataloggers 
alleviated this problem.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Instrument failure

A lightning strike caused a failure in the ORG.  Rainfall was being continually recorded.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - ORG data noisy due to degraded ground

SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse 
over time so that in February 2006 the ORG was reporting with a constant background value 
of around 0.10 mm/hr rain rate.  ORG voltage showed a near constant value above the 85mV 
threshold.  The ground for the ORG had become degraded and was lost due to corrosion.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)

TWP/SMET/C3 - Reprocess: Barometric pressure units change

Barometric pressure data during this time period is reported in hPa.  After this time, the 
data have been converted to kPa to standardize the measurement units among ARM sites and 
to conform to accepted standard units determined by the scientific community.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the SMET suite of instruments effective 20060926. 
 Two new variables (count and rain amount) were added at the end of the twpsmet60sC1.b1 
datastream.  When reprocessing of this datastream occurs these variables will be added 
with -9999 (missing) as the value for dates prior to gauge installation.

• base time(base_time)

TWP/SMET/C3 - Barometer Data Incorrect

The barometer data was incorrect or missing due to water intrusion.

• Barometric Pressure(atmos_pressure)

TWP/SMET/C3 - ORG overestimated rainfall

Optical rain gauge (ORG) measured approximately 10mm higher than two co-located tipping 
bucket rain gauges and a co-located disdrometer.  The ORG is typically higher but usually 
not by an order of magnitude.

• Precipitation mean(precip_mean)
• Precipitation maximum(precip_max)
• Precipitation standard deviation(precip_sd)
• precipitation minimum(precip_min)