HFE/MWR/M1 - Insufficient calibration stability

The noise diode temperature suddenly jumped to > 60 C after a power outage. Following 
additional power problems the noise diode injection temperature drifted fast and the 
radiometer was not able to calibrate properly.

Data during the indicated time periods are poorly calibrated and sometimes erratic. Users 
should be aware that the accuracy of the measurements is dramatically degraded. 

Users can use the microwave profiler (MWRP) data to supplement the MWR data.

• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• MWR column precipitable water vapor(vap)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Mixer kinetic (physical) temperature(tkxc)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• (tknd)

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)

HFE/MWR/M1 - Missing data

Data are missing and unrecoverable.

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Time offset of tweaks from base_time(time_offset)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• (tknd)
• time(time)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• lon(lon)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• MWR column precipitable water vapor(vap)
• lat(lat)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Blackbody kinetic temperature(tkbb)
• 31.4 GHz sky signal(sky31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Ambient temperature(tkair)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz Blackbody signal(bb23)
• Dummy altitude for Zeb(alt)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz sky signal(sky23)
• base time(base_time)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)

• 31.4 GHz goodness-of-fit coefficient(r31)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• Ambient temperature(tkair)
• Time offset of tweaks from base_time(time_offset)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Actual Azimuth(actaz)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• time(time)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• base time(base_time)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• lon(lon)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.4 GHz blackbody(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Dummy altitude for Zeb(alt)
• (tknd)
• Actual elevation angle(actel)
• 23.8 GHz Blackbody signal(bb23)
• lat(lat)
• 23.8 GHz sky signal(tipsky23)