NSA/GNDRAD/C1 - IRT cable failure

The IRT signal became very noisy and the problem was traced to the cable (after the 
instrument was returned to the vendor for diagnosis). The problem started occurring when ice 
surrounding the cable began to melt. The cable was repaired and the instrument reinstalled.

• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature, Standard Deviation(sfc_ir_temp_std)

NSA/GNDRAD/C1 - Reprocess: Longwave Calibration error

Modified pyrgeometer calibration procedures were implemented beginning in December 2003.  
These modified procedures introduced a calibration bias in the longwave data.  The 
previous procedures were re-implemented at all sites between December 2005 and February 2006 to 
restore proper calibrations.                                                             
                The data collected while the incorrect procedures were in place are 
being reprocessing to remove the calibration bias.  Note, this also affected standard 
deviation, maximum and minimum data fields.

• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)

NSA/GNDRAD/C1 - Net radiometer removed

The net radiometer was removed from the NSA.C1 GNDRAD instrument suite on Feb 3, 2000.  
Net rad variables were filled with garbage data until Sept 23, 2000 and with missing values 
(-9999) until 20041103.  The net rad variables were removed from the netcdf files after 
20041103.

A reprocessing task (RID-526) has been submitted to the queue to address the need to add 
metadata to the NSA.C1 GNDRAD netcdf files documenting the missing data as well as to move 
toward a consistent datastream format throughout time.

• base time(base_time)

• NET standard deviation(net_sd)
• NET mean(net_mean)
• Net Radiation, Standard Deviation(net_std)
• Net Radiation, Maxima(net_max)
• Net Radiation, Minima(net_min)
• Net Radiation(net)

NSA/GNDRAD/C1 - Reprocess: IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C. Measurements of surface temperature were over-estimated when instrument was below 
freezing.

Data will be reprocessed, but users can correct data using the following correction 
factor:

If T_reference < -5?C, then

  IRT_corrected = (IRT_original - 32.993K)/0.87238

where T_reference can be estimated with the ambient temperature (e.g. 
inst_up_long_hemisp_dome_temp or inst_up_long_dome_temp)

• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature, Standard Deviation(sfc_ir_temp_std)