Data Quality Reports for Session: 124328 User: kjohnson Completed: 11/16/2009


TABLE OF CONTENTS

DQR IDSubjectData Streams Affected
D081022.8TWP/SMET/C3 - Wind Speed data contain offset due to induced voltagetwpsmet60sC3.b1
D090515.1TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degreestwpsmet60sC3.b1


DQRID : D081022.8
Start DateStart TimeEnd DateEnd Time
03/12/2002000010/17/20080627
Subject:
TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage
DataStreams:twpsmet60sC3.b1
Description:
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.
Measurements:twpsmet60sC3.b1:
  • 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)


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DQRID : D090515.1
Start DateStart TimeEnd DateEnd Time
04/19/2005042004/04/20090115
Subject:
TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees
DataStreams:twpsmet60sC3.b1
Description:
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
Measurements:twpsmet60sC3.b1:
  • 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)


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