IRV
Irvine PAMS Site Surface Data Notes

Data collection started:  October 4, 2007

Inception to September 26, 2008 -- The temperature/relative humidity aspirator had 
a flow blockage preventing adequate ventilation of the sensors.  Data prior to this 
date should be used with care as it will be subject to solar radiation effects.

Sonic wind data at this site are from a 2-D instrument.  This particular instrument 
has known issues with periodic spikes in the wind speed data that affects both the 
calculated wind speed and wind direction data.  Audits performed at other stations 
have shown the data to be accurate when the spikes are not present.  However, it is 
not always apparent when the data may have been affected.

September 17, 2008 -- The sonic wind sensor failed and is no longer functional.

The data validation performed in August 2009 noted that the K&Z sensor has some
slightly positive nighttime values.  These values are less than 1% of the operating
range of the sensor.

The wind speed propeller was noted to be damaged during the maintenance on 
January 2, 2010.  The wind sensor was ultimately replaced on June 9, 2010.  A review
of the data during the period did show slightly reduced wind speeds relative to the 
prior data that could be due to the damaged propeller.  The wind speed values were
left in the data base but any user should be aware of the potential for the data to
be biased low.  The new sensor was operational starting at 10:30 PST.

September 3, 2010 -- Updated information on the wind speed analysis does show that
that the winds are biased slightly low during the period when the propeller was
damaged.  The imbalance of the prop also increased the frequency of the reported
calm winds.  Care should be exercised in the use of the winds for wind speed
sensitive applications.

September 3, 2010 -- A review of the Licor solar radiation data shows that the
sensor is likely shaded during the 1600 to 1800 hour.  The readings systematically
drop relative to the K&Z readings during this period, with specific hours depending
on the season.

December 21, 2010 -- A review of the K&Z solar radiation data shows that this 
sensor is now affected by a shadow during the month of August.  The issue affects
the data from the 1100 and 1200 hours.

January 31, 2011 -- A review of past RH data has shown the response to be dropping
with few values at or above 90%.  The sensor may need replacement.

April 14, 2011 -- Aspirator monitoring modules have been installed and as of this
date it was noted that the aspirator was not functioning.  Servicing will be
performed soon, but this may account for the RH values not going above 90%.  This
would also put a question on the temperature and RH data.

May 3, 2011 -- The 2011 data file now includes the last field for the aspirator
current.  In the months prior to the data logger program uploading an empty field
will be in the file (only a comma).  During the installation month the values for
aspirator current will appear.  The aspirator was not repaired until April 21, 2011.