DQRID : D050218.4
Start DateStart TimeEnd DateEnd Time Data Quality Metric
09/01/2004000004/30/20050000Suspect
more
Subject:
SGP/MFR10M/C1 - Dip in data at solar noon
DataStreams:sgpmfr10mC1.b1, sgpmfr10mC1.a0
Description:
On clear days there is a dip in the data (all channels) at solar noon that is more 
pronounced during the winter months.  While we currently don't know the cause of this dip, we 
believe it is related to reflections off the tower pole.  The working theory says at solar 
noon the north-south crossbar shades the tower pole cutting off reflections into the 
detector.  If true, this means data on either side of the dip are being enhanced by 
reflections and the data within the dip are actually "correct."  An experiment is being planned 
for next fall that will wrap the upper portion of the tower in a non-reflecting cloth.  
This should determine if the dip is related to reflections from the tower pole.

Since at this point we don't know if the dip consists of bad or good data, users should be 
aware there is a problem and treat all the data as suspect.  It should noted that the 
magnitude of the problem is relatively small, likely no greater than 2.5%, so the dataset 
as whole is probably still useful as is for most users.
Suggestions: 
Measurements:sgpmfr10mC1.b1:
  • up_hemisp_broadband
  • up_hemisp_narrowband_filter6
  • up_hemisp_narrowband_filter4
  • up_hemisp_narrowband_filter5
  • up_hemisp_narrowband_filter2
  • up_hemisp_narrowband_filter3
  • up_hemisp_narrowband_filter1
more
sgpmfr10mC1.a0:
  • up_hemisp_narrowband_filter1
  • up_hemisp_broadband
  • up_hemisp_narrowband_filter3
  • up_hemisp_narrowband_filter2
  • up_hemisp_narrowband_filter5
  • up_hemisp_narrowband_filter4
  • up_hemisp_narrowband_filter6
more

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