TWP/SMET/C3 - Data non-representative

Tower mast was lowered for inspection.  Data during this time is non-representative.

• Lower sensor, wind speed minimum(lo_spd_min)
• Precipitation maximum(precip_max)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• precipitation minimum(precip_min)
• Upper sensor, wind speed maximum(up_spd_max)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Vapor pressure mean(vappress_mean)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Barometric Pressure(atmos_pressure)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Vapor pressure standard deviation(vappress_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation mean(precip_mean)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Precipitation standard deviation(precip_sd)
• Upper sensor, wind speed minimum(up_spd_min)
• Tipping bucket raingauge count total(tbrg_count_total)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)

TWP/SMET/C3 - Lower wind direction sensor failure

The lower wind direction sensor failed on 4/14 and disagrees significantly with the upper 
wind direction sensor.  The lower wind sensor reports a constant value around 0-15 
degrees since it failed.  Testing showed that excitation channel two on the logger was the 
problem.  Logger was replaced by spare.

• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Lower sensor, wind direction standard deviation(lo_dir_sd)

TWP/SMET/C3 - Data not representative

Tower was lowered for radiometer change and characterization. Data are not representative 
of local conditions.

• Lower sensor, wind speed minimum(lo_spd_min)
• Precipitation maximum(precip_max)
• Lower sensor, wind direction standard deviation(lo_dir_sd)
• precipitation minimum(precip_min)
• Upper sensor, wind speed maximum(up_spd_max)
• Tipping bucket raingauge total(tbrg_total)
• Mean Air Temperature or Hardware Error(temp_mean)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Vapor pressure mean(vappress_mean)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Barometric Pressure(atmos_pressure)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Vapor pressure standard deviation(vappress_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Mean Relative Humidity(relh_mean)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Precipitation mean(precip_mean)
• Lower sensor, wind direction vector average(lo_dir_vec_avg)
• Precipitation standard deviation(precip_sd)
• Upper sensor, wind speed minimum(up_spd_min)
• Tipping bucket raingauge count total(tbrg_count_total)
• Upper sensor, wind speed standard deviation(up_spd_sd)
• Std Dev of Air Temperature(temp_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)

TWP/SMET/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

• Upper sensor, wind speed maximum(up_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Upper sensor, wind direction vector average(up_dir_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Upper sensor, wind direction standard deviation(up_dir_sd)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - RH Values Artificially High

Lightning strike caused RH readings to be higher than reasonable (130%).

• Vapor pressure standard deviation(vappress_sd)
• Mean Relative Humidity(relh_mean)
• Vapor pressure mean(vappress_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)

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: 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 - 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.

• Upper sensor, wind speed maximum(up_spd_max)
• Lower sensor, wind speed minimum(lo_spd_min)
• Lower sensor, wind speed standard deviation(lo_spd_sd)
• Lower sensor, wind speed maximum(lo_spd_max)
• Upper sensor, wind speed arithmetic average(up_spd_arith_avg)
• Lower sensor, wind speed vector average(lo_spd_vec_avg)
• Upper sensor, wind speed minimum(up_spd_min)
• Lower sensor, wind speed arithmetic average(lo_spd_arith_avg)
• Upper sensor, wind speed vector average(up_spd_vec_avg)
• Upper sensor, wind speed standard deviation(up_spd_sd)

TWP/SMET/C3 - Reprocess: Temperature data biased low

Due to a datalogger problem, the temperature data were biased low by 2.13 degrees C.

The data will be reprocessed.

• Mean Air Temperature or Hardware Error(temp_mean)
• Std Dev of Air Temperature(temp_sd)

TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees

The temperature of the SMET system was biased low by 1.06 Deg C due to a non-precision 
resistor being used int he measurement circuit.  The data will be reprocessed.  Saturation 
Vapor pressure and Vapor pressure will have to be reprocessed also.

Add 1.06 degrees to the temperature data.  

Correct Sat Vap Press using the Buck approximation:
   Es = 6.1121exp((17.502*T)/(240.97 + T) 
where T is the temperature in C.  

Correct Vapor pressure using: E = (RH*Es)/100

• Vapor pressure standard deviation(vappress_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Vapor pressure mean(vappress_mean)
• Std Dev of Air Temperature(temp_sd)