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/MPL/M1 - Frosting/Condensation

On various days during the China deployment, condensation accumulated on the view port 
window of the MPL and compromised its capability to detect clouds.  This problem most often 
occurred during nighttime hours from May through early September.  

During the listed times, cloud retrievals and aerosol profiles should be considered 
doubtful or in error.

The dates/times of occurrence are:
16:00-23:59 GMT on 05/18
17:00-22:00 GMT on 05/23
20:00-22:00 GMT on 05/25
15:00-23:59 GMT on 06/07
17:00-23:59 GMT on 06/08
15:00-23:00 GMT on 06/09
14:00-18:00 GMT on 06/18
18:00-21:00 GMT on 06/21
14:00-16:00 GMT on 06/23
16:00-21:00 GMT on 06/27
17:00-20:00 GMT on 06/28
      22:00 GMT on 06/29
19:00-23:00 GMT on 06/30
13:30-22:30 GMT on 07/02
16:00-17:30 GMT on 07/03 
20:30-22:00 GMT on 07/03
21:30-22:30 GMT on 07/05
13:00-22:00 GMT on 07/06
17:00-18:00 GMT on 07/07
21:00-22:30 GMT on 07/07
16:00-23:59 GMT on 07/10
11:00-23:00 GMT on 07/11
18:00-23:00 GMT on 07/12
15:00-16:00 GMT on 07/13
18:00-23:59 GMT on 07/14
18:00-21:00 GMT on 07/15
17:30-23:00 GMT on 07/16
17:00-23:00 GMT on 07/17
13:00-23:30 GMT on 07/20
18:00-23:00 GMT on 07/24
21:00-23:00 GMT on 07/25
21:00-22:30 GMT on 07/27
12:00-23:59 GMT on 08/02
16:00-21:30 GMT on 08/03
16:00-23:00 GMT on 08/04
14:00-22:30 GMT on 08/05
19:00-23:00 GMT on 08/07
19:00-21:30 GMT on 08/08
15:00-23:30 GMT on 08/10
17:30-23:30 GMT on 08/12
14:00-15:00 GMT on 08/14
16:30-22:30 GMT on 08/14
21:30-22:30 GMT on 08/17
12:00-23:59 GMT on 08/18
12:00-13:30 GMT on 08/19
20:00-23:30 GMT on 08/19
15:00-23:59 GMT on 08/20
11:00-23:59 GMT on 08/22
11:00-23:30 GMT on 08/23
12:00-23:30 GMT on 08/25
13:00-23:30 GMT on 08/26
16:30-23:59 GMT on 08/27
17:00-23:00 GMT on 08/31
15:00-23:59 GMT on 09/01
15:00-20:00 GMT on 09/02
19:30-23:59 GMT on 09/05
16:30-22:30 GMT on 09/09
19:30-23:59 GMT on 09/12
20:30-23:59 GMT on 09/15
14:00-16:30 GMT on 09/16
19:00-23:59 GMT on 09/16
20:30-23:59 GMT on 10/29
22:00-23:59 GMT on 11/01
20:00-23:59 GMT on 11/23
00:00-02:00 GMT on 11/24

• lon(lon)
• *(aqc_signal_return_cross_pol)
• Detector Temperature(detector_temp)
• Background signal standard deviation, cross-pol(background_signal_std_cross_pol)
• Dead time correction flag(dead_time_corrected)
• Dummy altitude for Zeb(alt)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• *(aqc_signal_return_co_pol)
• range(range)
• Number of samples used for cross-pol averages(nsamples_cross_pol_average)
• Number of detector channels(num_channels)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• Laser output energy per pulse(energy_monitor)
• lat(lat)
• Number of bins stored in data block(num_bins)
• base time(base_time)
• Background signal, co-pol(background_signal_co_pol)
• Preliminary cloud base height above ground level, co-pol(preliminary_cbh_co_pol)
• Polarization control voltage, cross-pol(polarization_control_voltage_cross_pol)
• Number of samples used for co-pol averages(nsamples_co_pol_average)
• Telescope temperature(scope_temp)
• Background signal standard deviation, co-pol(background_signal_std_co_pol)
• Attenuated backscatter, cross-pol(signal_return_cross_pol)
• Number of laser pulses summed during averaging interval(shots_per_sample)
• Background signal, cross-pol(background_signal_cross_pol)
• Time offset of tweaks from base_time(time_offset)
• Array of heights for the range gates(height)
• Polarization control voltage, co-pol(polarization_control_voltage_co_pol)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Preliminary cloud base height above ground level, cross-pol(preliminary_cbh_cross_pol)
• Attenuated backscatter, co-pol(signal_return_co_pol)
• time(time)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Laser Temperature(laser_temp)

• Preliminary cloud base height(preliminary_cbh)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Polarization control enabled flag(polarization_control)
• lat(lat)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• Attenuated backscatter(signal_return)
• Number of laser pulses summed during averaging interval(shots_per_avg)
• Laser Temperature(laser_temp)
• base time(base_time)
• Number of bins stored in data block(num_bins)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)
• Dummy altitude for Zeb(alt)
• Array of heights for the range gates(height)
• Background signal standard deviation(background_signal_std)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• Number of detector channels(num_channels)
• lon(lon)
• Background Signal(background_signal)
• Polarization control voltage setting(polarization_control_voltage)
• Telescope temperature(scope_temp)
• Detector Temperature(detector_temp)
• Dead time correction flag(dead_time_corrected)
• range(range)
• Time offset of tweaks from base_time(time_offset)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• time(time)
• Time in nanoseconds for each range bin of multichannel scalar card.(range_bin_time)
• Laser output energy per pulse(energy_monitor)

• lat(lat)
• base time(base_time)
• Background signal, co-pol(background_signal_co_pol)
• Laser Temperature(laser_temp)
• Dead time correction flag(dead_time_corrected)
• Number of samples used for cross-pol averages(nsamples_cross_pol_average)
• Attenuated backscatter, co-pol(signal_return_co_pol)
• Dummy altitude for Zeb(alt)
• Number of laser pulses summed during averaging interval(shots_per_sample)
• Polarization control voltage, co-pol(polarization_control_voltage_co_pol)
• Background signal, cross-pol(background_signal_cross_pol)
• time(time)
• Laser output energy per pulse(energy_monitor)
• Time offset of tweaks from base_time(time_offset)
• Array of heights for the range gates(height)
• Background signal standard deviation, co-pol(background_signal_std_co_pol)
• Telescope temperature(scope_temp)
• Background signal standard deviation, cross-pol(background_signal_std_cross_pol)
• Preliminary cloud base height above ground level, cross-pol(preliminary_cbh_cross_pol)
• Preliminary cloud base height above ground level, co-pol(preliminary_cbh_co_pol)
• Number of bins stored in data block(num_bins)
• *(aqc_signal_return_co_pol)
• Repetition Rate, or Trigger Frequency of the laser(pulse_rep)
• Attenuated backscatter, cross-pol(signal_return_cross_pol)
• *(aqc_signal_return_cross_pol)
• Number of detector channels(num_channels)
• Width of range-bins calculated from range_bin_time(range_bin_width)
• Number of samples used for co-pol averages(nsamples_co_pol_average)
• lon(lon)
• effective range offset due to poor sync between laser firing and A/D trigger.(range_offset)
• Detector Temperature(detector_temp)
• Distance from leading edge of first range bin to the center of each bin .(range_bins)
• Polarization control voltage, cross-pol(polarization_control_voltage_cross_pol)
• range(range)
• Maximum altitude retrieved from multichannel scalar card.(max_altitude)

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)