HFE/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 arithmetic average(wind_spd_arith_avg)
• Wind speed arithmetic maximum(wind_spd_arith_max)
• Wind speed arithmetic minimum(wind_spd_arith_min)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Wind speed arithmetic standard deviation(wind_spd_arith_sd)

HFE/MET/M1 - Intermittent barometer failure

Intermittent barometer failure occurred throughout the deployment.  We were unable to 
pinpoint the cause of the failure.  Typically one or two minutes of missing data occurred 
every few days.

Since pressure data is typically invariant over 1 minute, linear interpolation should be 
fine to fill in missing data.

• Barometric Pressure(atmos_pressure)

HFE/MET/M1 - Intermittent PWD data

The Present Weather Detector had intermittent missing values throughout this deployment.  
Missing values occurred almost everyday, usually just one or two minutes per day.

• 1 minute average water intensity(pwd_avg_H2O_int_1_min)
• 15 min present weather code(pwd_pw_code_15_min)
• Average 10 min visibility(pwd_avg_vis_10_min)
• Average 1 min visibility(pwd_avg_vis_1_min)
• 1 hour present weather code(pwd_pw_code_1_hr)
• Instantaneous present weather code(pwd_pw_code_inst)
• Cumulative water(pwd_cumul_water)
• Present weather detector error code(pwd_err_code)
• Present weather detector ID(pwd_id)
• Cumulative snow(pwd_cumul_snow)

HFE/MET/M1 - ORG Measuring Ice Crystals or Fog

The ORG was measuring consistent values for long periods of time.  Typically this is 
indicative of fog, ice crystals in the air or poor performance of the lens heaters.

• Precipitation rate standard deviation(precip_rate_sd)
• Precipitation rate minimum(precip_rate_min)
• Precipitation rate mean(precip_rate_mean)
• Precipitation rate maximum(precip_rate_max)

HFE/MET/M1 - Induced voltage on wind speed sensor cable

The cable for the wind monitor is not a twisted pair shielded cable.  This caused an 
induced voltage on the wind sensor wires from the wind direction measurement excitation 
voltage.  A small offset is added into the wind speeds.  This value varies.  Most frequently 
the values of 0.49, 0.588 and 0.686 m/s were added into the wind speed.  On 11/27/2008 the 
value jumped to 0.98 m/s for most of the day.

• Wind speed arithmetic average(wind_spd_arith_avg)
• Wind speed arithmetic maximum(wind_spd_arith_max)
• Wind speed arithmetic minimum(wind_spd_arith_min)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Wind speed arithmetic standard deviation(wind_spd_arith_sd)