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/MWRHF/M1 - Calibration updates

The MWRHF calibration algorithm updates the calibration parameters every time a new 
successful tip curve is acquired. 

This results in small jumps (1-2 K) in the brightness temperatures each time calibration 
is updated. During times of frequent calibrations the data appear discontinuous with short 
data segments interrupted by small jumps.

• Sky brightness temperature (150 GHz)(tbsky150)
• Sky brightness temperature (90 GHz)(tbsky90)

HFE/MWRHF/M1 - Rain sensor failure

The rain sensor failed and the rain flag was always on.  When the rain flag is on the 
radiometer does not perform tip curves. The rain sensor was replaced 8/4.

• Rain flag(rain_flag)

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 - 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/MWRP/M1 - Reprocess: Bias in LWP retrievals

Since local radiosondes were not available, radiosondes from a different site were used to 
develop retrieval coefficients. LWP retrievals are biased in the summer months 
(June-September).  Data in May and December are not affected.

Additional analysis will be conducted to derive new retrieval coefficients and the data 
will be reprocessed.

• Retrieved liquid water path(liquidWaterPath)
• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)

HFE/NFOV/M1 - Over-ranging data

The instrument was incorrectly installed with an incorrect range setting in the logger 
program.  The program for lamp calibrating the instrument was used, and not the operational 
program. The scale ranges are different, and this resulted in over-ranging conditions 
when the signal exceeded the upper end of the measurement scale.  Affected times are 
centered around solar noon, nominally +/- one-hour around solar noon.  This lasted until 
mid-Aug, when the highest signals were no longer exceeding the logger range.

• Raw counts from instrument before calibration, 870 nm(raw_counts_870nm)
• Calibrated Zenith Radiance, 870 nm(radiance_870nm)
• Raw counts from instrument before calibration, 673 nm(raw_counts_673nm)
• Calibrated Zenith Radiance, 673 nm(radiance_673nm)