NIM/MET/M1 - ORG Data Underestimated Precipitation

The ORG underestimated precipitation by about 38% during the entire NIM deployment.  No 
troubleshooting technique or replacement of gage was successful in correcting the problem.

• precip_rate_min
• org_carrier_mean
• Rain, surface, 1-min avg(precip_rate_mean)
• precip_rate_max
• precip_rate_sd

NIM/MET/M1 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we
   continuously collect data even when no rain is occurring.  We also capture
   small events such as leaves, large bugs, dust, etc blowing through the
   measurement path.  Because this discrete event occurs quickly the value is
   usually captured for 1 or 2 seconds.  This value is then averaged to the
   minute producing rainrate on the order of .009 mm/hr or less.  These values
   are not indicative of rain and should be removed from the record or summing
   over long periods can bias the climate record.  We are reprocessing the data
   to remove these small values and are adjusting the collection program to
   remove them before ingest.

• precip_rate_min
• Rain, surface, 1-min avg(precip_rate_mean)
• precip_rate_max
• precip_rate_sd

NIM/MET/M1 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• Wind speed, lower, 1-min avg(wind_spd_arith_avg)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• wind_spd_arith_min
• wind_spd_arith_max
• wind_spd_arith_sd

NIM/MET/M1 - Present Weather Detector Cumulative Precipitation in Error

The Present weather detector is a serial sensor.  The MET system datalogger reads in the 
data from this sensor.  During the time in question serial comms problems were causing the 
data from the sensor to be read incorrectly.  The data for one variable showed up in 
data for another variable or not at all.  We reprocessed the data to correct as much of this 
error as we could.  The cumulative rainfall variable was calculated from the 
instantaneous rainfall variable during reprocessing.  Since we cannot be entirely sure all 
cumulative rainfall values are correct or were completely captured the cumulative rainfall data is 
considered to be unreliable.  This issue shows up when comparing the cumulative rainfall 
data at the end of the day 07/31/2006 (79.08) and the beginning of the next day 
08/01/2006 (3.17).  Clearly we were either under or over-estimating the cumulative rainfall.

• pwd_cumul_water

NIM/MET/M1 - Present Weather Detector 1 Minute Rainfall Data Suspect

The Present weather detector is a serial sensor.  The MET system datalogger reads in the 
data from this sensor.  During the time in question serial comms problems were causing 
the data from the sensor to be read incorrectly.  The data for one variable showed up in 
data for another variable or not at all.  We reprocessed the data to correct as much of 
this error as we could. We cannot be entirely certain that all rainfall values are correct 
or were captured properly.  It is possible that some values were missed completely.

• pwd_avg_H2O_int_1_min