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Data Corrections

Last updated: 30 April 2008
Although quality control procedures are routinely followed during the transformation of raw data to data products disseminated through this web site or by special request from the program office, subsequent corrections are sometimes necessary. The table below provides brief descriptions of some of these changes. The absence of information regarding a given site and time period is not an indication that no change has been made. Only the most serious errors which affect substantial amounts of data are given here. Changes can potentially impact multiple data products derived from the affected data. Users concerned about the effects of changes on their studies are encouraged to download data periodically to ensure the currency of their files. Users may also contact UVB personnel for further information.

Location Dates Affected (yyyy-mm-dd)     Changed (yyyy-mm-dd) Description
All Locations 1994 - 2007-12-31 2008-01-21 The daily vnaughts for our visible wavelength range have been regenerated using a simple linear regression technique. The previous method, Dr. Joseph Michalsky's Forgan technique (Michalsky et al., 2001) has been dicontinued.
All Locations 2001 - 2007-12-11 2007-12-11 As of December 11, 2007, it was found that the Langley calibrated irradiances were in error by about +/- 3.5%. The Langley calibrations are now corrected to properly account for earth-sun distance. Previous Langley Calibrations were about 3.5% too small in January and 3.5% too large in July. Since all irradiances are calibrated at the time of the user's request, any Langley calibrated data will now reflect the proper earth-sun distance factor regardless of the date and time of the measured data.
All Locations 2001 - 2007-07-02 2007-07-02 Significant improvement in most Calibrated Data after 2001 was implemented on July 2, 2007. Lamp-calibrated irradiance values for the 311, 317, 325, 332, 368 channels have increased, on average, 8.8%, 22.1%, 12.1%, 11.2%, and 4.0% respectively. The 300 and 305 channels are essentially unchanged as well as the Langley calibrated data. For more detailed information click here.
All Locations 2004-02-01 - 2004-02-10 2005-02-05 Errant "bc2" QC flags pertaining to UVB-1 broadband data removed.
All Locations 2005-01-01 - 2005-01-25 2005-01-27 Erythemal calibration problem for UVB-1 broadband data corrected.
Alaska, Fairbanks(C) 2004-05-21 - 2004-06-15 2004-06-16 QC flags added for VIS-MFRSR band motion problem.
Arizona, Flagstaff(C) 199704-24 - 199710-09 2004-05-26 UV-MFRSR Irradiances re-calibrated using CSU board gains.
California, Davis(C) 2001-01-01 - 2001-12-31 2002-08-01 - 2002-08-02 UV-MFRSR Irradiances corrected to compensate for faulty offset values.
California, Holtville(C) 2004-07-01 - 2005-03-31 Problem with VIS-MFRSR 665nm channel; data unusable at this time; corrections pending; end of affected period uncertain.
Colorado, Longmont(R) 2005-11-10 - 2005-12-02 2006-03-27 Angular corrections and calibration data changed to use correct serial number data.
2003-06-23 - 2003-09-28 2003-10-20 (approximate) UV-MFRSR Angular corrections changed from YES file to CUCF file.
2003-06-23 - 2003-10-01 2004-01-28 UV-MFRSR Calibration error corrected. Problem began 031014.
Colorado, Nunn(C) 1999-11-10 - 1999-11-11 2005-02-07 QC flags added for ground loop problem in UVB-1 broadband data.
Florida, Homestead(C) 2006-01-17 - 2006-10-12 2006-10-12 UV-MFRSR Calibration error corrected.
Hawaii, Waimea(C) 2004-01-29 - 2004-03-31 2004-06-22 UV-MFRSR Calibration error corrected.
Illinois, Bondville(C) 2006-03-07 - 2006-04-07 2006-04-07 UV-MFRSR Angular corrections error corrected.
Louisiana, Baton Rouge(C) 2005-10-01 - 2006-03-31 2006-04-05 UV-MFRSR Angular corrections changed to a newer file from CUCF
2006-03-21 - 2006-03-29 2006-04-05 Diffuser Dirty quality control flag was added to the Vis-MFRSR and UV-MFRSR data. Wavelength channel data, PAR data and UVB-1 broadband data was impacted.
Maine, Presque Isle(C) 1998-12-11 - 1998-12-18 2005-02-08 Data's timestep was off by 2 hours.
Maryland, Beltsville(C) 2005-07-17 - 2005-08-10 2005-08-15 QC flags added for VIS-MFRSR failure.
Maryland, Greenbelt(R) 2004-03-26 - 2004-05-26 2004-09-10 New UV-MFRSR angular corrections & calibration applied.
Michigan, Pellston(C) 2004-07-14 - 2005-08-22 2005-08-22 QC flags for sudden drop in VIS-MFRSR sensitivity added early each month for the previous month. Data corrections completed 050907.
New Mexico, Las Cruces (C) 1997-05-01 - 1997-10-22 2004-07-01 UV-MFRSR Calibration error corrected.
2000-11-14 - 2000-11-27 2004-04-09 - 2004-04-12 QC flags added for VIS-MFRSR band alignment problem; data unusable.
2003-06-11 - 2004-05-04 Problem with VIS-MFRSR 665nm channel; data unusable at this time; corrections pending.
North Carolina, Raleigh(C) 2007-11-01 - 2008-03-31 2008-04-30 Wrong Broadband calibration factor was applied.
Montana, Poplar(C) 2006-11-09 - 2006-11-16 2006-11-16 Broadband calibration factors not applied.
New York, Geneva(C) 2006-07-11 - 2006-10-12 2006-10-13 Wrong calibration factors where applied.
Oklahoma, Billings(C) 2004-06-02 - 2005-02-17 2005-03-10 QC flags added for sudden drop in VIS-MFRSR 610 & 665nm sensitivity.
2005-07-20 - 2005-08-24 monthly QC flags for sudden change in VIS-MFRSR sensitivity added early each month for the previous month until further notice.
2006-08-01 - present 2006-12-07 QC flags for channel failure for open, 415 and 940 added. Data should not be used
Ontario, Toronto(C) 2005-11-01 - 2006-03-20 2006-03-20 Faulty UV-MFRSR Angular corrections applied. Channel 368 was affected.
Texas, Panther Junction(C) 2004-08-09 - 2004-10-27 2004-10-20 QC flags added for sudden drop in VIS-MFRSR sensitivity.
Texas, Seguin(C) 2006-08-01 - 2008-03-31 2008-04-30 Wrong par calibration factor was applied.