NIP (pyrheliometer) calibration coefficient slightly wrong

DQR No:                               Platform: SIROS

Subject: Site E2 - NIP (pyrheliometer) calibration coefficient
slightly wrong for a period of 5 days

Date Submitted: 1 May 1996
Submitted By: Jim Barnard             _X_  Instrument Mentor
                                      ___  EST Member
                                      ___  Science Team Member
                                      ___  Other _____________________________
 
For questions or problems, please contact the ARM Experiment Center at
509-375-6898 or via email at problems@arm.gov.

Platform/Measurement:
        What level data: (raw,a0,a1,b1,c1 etc): a1

    What location was the data collected at: 
 
    Period of time in question
        Begin Date   96/04/19  Time   15:20    (GMT)
        End Date     96/04/24  Time   00:00    (GMT)
        (For the NIP, some errors are occasionally observed after the "End Date").

Data should be labeled:
 ___  questionable                      ___  All data fields affected
 ___  incorrect                         _x_  Only some data fields affected
 _x_  wrong calibration
 ___  others 
 

 Discussion of Problem:  The NIP (pyrheliometer) at site E2 was changed
on April 19, 1996 at about 1530 GMT.  When the NIP was changed, the data
ingest was not turned off and continued insouciantly.  Later, the mentor 
was informed about the change and a new calibration file was submitted.
This file was applied to the ingested data about April 24, 1996.
Instead of redoing the ingest from April 19, 1996 to April 24, 1996,
we are submitting this DQR to inform people that the NIP calibration 
during this time period is not correct.  The calibration factor
applied to these data during this period is 8.513 x 10^-6 Volts/W/M^2,
while the true calibration factor is 8.546 x 10^-6 Volts/W/M^2.  This
factor is being applied to all the NIP data collected from April 24, 1996
on.  Note that the error caused by using the incorrect calibration
factor is less than 0.4%. 




Other observations/measurements impacted by this problem:



Suggested Corrections of the Problem: (e.g. change calibration factor and
recompute, flag data with this comment, etc.)

The error is so small that it can probably be ignored; from a
practical standpoint, this DQR is submitted for the sake of
completeness.

• lon(lon)
• Ventilated Pyrgeometer Dome Temperature(down_long_dome_temp)
• Downwelling Longwave Diffuse Hemispheric Irradiance, Ventilated Pyrgeometer(down_long_diffuse_hemisp)
• Data Logger Temperature(logger_temp)
• Diffuse Hemispheric Irradiance, MFRSR(diffuse_hemisp_narrowband)
• Thermistor Excitation Voltage, Data Logger(therm_volt)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• Ventilated Pyrgeometer Case Temperature(down_long_case_temp)
• Direct Normal Irradiance, MFRSR(direct_norm_broadband)
• 25 meter Longwave Case Temperature, Pyrgeometer(up_long_case_temp)
• 10 meter Longwave Dome Temperature, Pyrgeometer(up_long_dome_temp)
• Flag fields with *2 returned from callang(flag_ln_error1-24)
• Data logger supply voltage(logger_volt)
• base time in epoch(base_time)
• Direct Normal Irradiance, NIMFR(direct_norm_narrowband)
• Flag fields with *4 returned from callang(flag_nighttime1-24)
• Time offset from base_time(time_offset)
• MFRSR channels(channel)
• -180.0 - +180.0(alt)
• Flag fields with *3 returned from callang(flag_zero_cosine1-24)
• North Latitude(lat)
• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• Flag fields with *1 returned from callang(flag_zero_divisor1-24)
• Hemispheric broadband irradiance(hemisp_broadband)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• 25 meter Upwelling Shortwave Hemispheric Irradiance, Pyranometer(up_short_hemisp)
• Diffuse Hemispheric Broadband Irradiance, offset corrected(diffuse_hemisp_broadband)
• 10 meter Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)
• MFRSR Detector Temperature(mfrsr_temp)
• Hemispheric Irradiance, MFRSR(hemisp_narrowband)