TWP/SKYRAD/C2 - UVB Data questionable/incorrect due to uncontrolled sensor temperature

The UVB was not temperature controlled to 25C as required
to ensure accurate data.  UVB data should ONLY be used after 
checking both the bit_data and twpskyrad20sC1.a1 uvb_temp
or inst_down_uvb_temp.  UVB data where the UVB temperature
was outside the range of 24-26C should not be used.

• inst_down_uvb_temp
• Irradiance, ultraviolet, downwelling (UV Biometer)(inst_down_uvb_irradiance)

• Downwelling Ultra-Violet Irradiance, UV Biometer, Maxima(down_uvb_max)
• down_uvb_std
• Downwelling Ultra-Violet Irradiance, UV Biometer, Minima(down_uvb_min)
• Downwelling Ultra-Violet Irradiance, UV Biometer(down_uvb)

TWP/GNDRAD/C2 - incorrect IRT calibration

When the GNDRAD data logger was upgraded, the calibration offset for the IRT was initially 
incorrect.

• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)

TWP/SKYRAD/C2 - IRT bias

The IRT appears to be measuring higher sky temperatures than the AERI. There is no 
indication as to its cause or whether the IRT or the AERI is at fault.

PRB note: because the AERI is calibrated between each sample, the AERI
data has a high degree of confidence and the bias is likely on the part
of the IRT.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_min

TWP/SKYRAD/C2 - IRT bias

The IRT was measuring higher sky temperatures than AERI. The problem was corrected by 
changing the mirror.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

TWP/GNDRAD/C2 - IRT connector

The IRT had a problem with the connector of either the signal or power cable which 
produced an output of 0 volts equivalent to a measurement of 223K. The problem was corrected 
when the connectors were cleaned and tightened.

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

TWP/GNDRAD/C2 - IRT power supply failed

The IRT output dropped to its minimum output of 223 K (0 volts).  It was determined the 24 
V DC converter had failed.  The converter was replaced on 16 August and the instrument 
began reporting normally again.  The IRT data are unusable during the five day period when 
the DC converter was faulty.

The GNDRAD (down-looking) IRT is used primarily for surface temperature.  The PIR can be 
used for this purpose by inverting the IR flux equation, Flux = sigma*temperature^4 where 
sigma = 5.67x10-8 W/m^2K^4.  But, unlike the IRT, the PIR measurement is strongly 
effected by the air temperature in addition to the surface temperature.  At night, when the air 
temperature approaches the surface temperature, the PIR provides a good estimate of the 
surface temperature.  During the day, however, the PIR tends to underestimate the ground 
temperature,  particularly on sunny days.  The magnitude of the underestimate can be 
estimated by evaluating periods when both instruments are operating but is typically on the 
order of 5-10C.

• irt1_mean
• irt1_sd
• irt1_min
• irt1_max

• Raw data stream - documentation not supported

TWP/GNDRAD/C2 - Gndrad inverted for radiometer

Gndrad instruments PIR and PSP inverted for replacement instrument
installation and comparison

• psp1_min
• sfc_ir_temp_std
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• pir1_min
• pir1_max
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• psp1_mean
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• psp1_max
• up_short_hemisp_std
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• psp1_sd
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• up_long_hemisp_std
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• pir1_mean
• pir1_sd

TWP/SKYRAD/C2 - Reprocess: Incorrect datalogger program affecting PIR1 and PIR2 
downwelling longwave

The excitation delays using in measuring the PIR1 case thermistor commonly named "Case1" 
and the PIR2 dome thermistor called "Dome2" were discovered to have been incorrectly set 
to 0 in the Skyrad datalogger program when the new CR23X based Skyrad loggers were 
installed.  The result of no delay in these measurements results in an error in the measured 
resistance of the thermistors, Case1 and Dome2, and thus the calculated PIR1 and PIR2 
irradiances.  The absolute value of the errors are inversely proportial to temperature.

Users can apply the temperature dependent irradiance corrections shown in the table below. 
 Recall that the reported uncertainty of PIRs is typically +-.25% to +-.5% or 1 to 2 
W/m2. The error corrections become the same order of magnitude or larger than the instrument 
uncertainties at or below 260K or 9F.
 
Irradiance Correction Table for Skyrad (TWP and NSA) DIR1 and DIR2 Irradiance
		DIR1	DIR1	DIR2	DIR2
	T[F]	Tcase[K]	Correction[W/m2]	Tdome[K]       
		Correction[W/m2]
	109.4	316.13	0.00	316.13	0.00
	100.5	311.20	-0.15	311.20	0.12
	93.2	307.14	-0.12	307.14	0.10
	87.0	303.70	-0.10	303.70	0.08
	81.6	300.70	-0.17	300.70	0.14
	77.0	298.15	-0.22	298.15	0.18
	59.4	288.35	-0.34	288.35	0.27
	47.4	281.72	-0.23	281.72	0.18
	38.5	276.74	-0.42	276.74	0.34
	31.3	272.77	-0.48	272.77	0.38
	25.4	269.48	-0.61	269.48	0.49
	20.3	266.67	-0.67	266.67	0.54
	16.0	264.25	-0.82	264.25	0.66
	12.1	262.11	-0.98	262.11	0.79
	8.7	260.19	-0.97	260.19	0.78
	5.6	258.46	-1.07	258.46	0.86
	2.7	256.89	-1.17	256.89	0.94
	0.1	255.44	-1.33	255.44	1.07
	-2.3	254.11	-1.41	254.11	1.13
	-4.5	252.87	-1.43	252.87	1.15
	-6.6	251.71	-1.52	251.71	1.22
	-8.5	250.63	-1.63	250.63	1.31
	-10.4	249.62	-1.73	249.62	1.39
	-12.2	248.58	-1.79	248.58	1.44
	-15.4	246.82	-1.93	246.82	1.55
	-18.3	245.23	-2.05	245.23	1.65
	-20.9	243.78	-2.22	243.78	1.78
	-23.3	242.44	-2.36	242.44	1.89
	-25.5	241.21	-2.58	241.21	2.07
	-27.5	240.07	-2.65	240.07	2.13
	-29.5	239.01	-2.75	239.01	2.21
	-31.3	238.00	-3.02	238.00	2.42

• down_long_hemisp_shaded1_max
• down_long_hemisp_shaded2_min
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded1_min
• down_long_hemisp_shaded2_std
• down_long_hemisp_shaded2_max
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)

• inst_down_long_shaded1_case_resist
• inst_down_long_shaded2_dome_resist
• inst_down_long_shaded1_dome_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded1_tp)
• inst_down_long_shaded2_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer2)(inst_down_long_hemisp_shaded2_tp)

TWP/SKYRAD/C2 - 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.

• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)

TWP/GNDRAD/C2 - 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.

• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)

TWP/SKYRAD/C2 - IRT signal loss

There was a significant drop in logger voltage that corresponds with a loss of the IR 
temperature. This was possibly due to a loose connection.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

TWP/SKYRAD/C2 - IRT signal

The IRT exhibited a bias of the analog voltage output that caused problems with the 
signals from the other SKYRAD radiometers. The bias was due to corrosion between the power and 
signal connections in the IRT cable. The IRT was disconnected on 10/18/2006 at 01:20 and 
replaced on 11/6/2006 at 23:00 but it too appeared to have grounding problems due to 
internal corrosion and was disconnected on 11/11/2006 at 11:42 and then intermittently 
reconnected for testing. A second spare was installed on 12/4/2006 which did not cause problems 
with the signals from the other instruments.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

TWP/GNDRAD/C2 - IRT signal

When the other GNDRAD radiometers were replaced on 12/3/2006, the quality of the IRT 
signal began to degrade until 12/26 when it became unusable. The instrument was replaced on 
2/4/2007.

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

TWP/SKYRAD/C2 - Short direct normal

The short_direct_normal (NIP) data are missing or incorrect due to instrument cable 
failure.  The cable was replaced.

The short_direct_normal can be calculated using the following relationship for shortwave 
radiometers:
global hemispheric = diffuse hemispheric + direct normal *cos (zenith angle)

• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• short_direct_normal_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal

TWP/SKYRAD/C2 - IRT measurement error

The IRT was not properly calibrated and was not able to measure sky temperatures below 
273.2 K. (This instrument was the same one damaged by lightning in November 2005 in Darwin. 
It was returned for repair and received a new lens but was calibrated only down to 0 deg 
C, so the problem was neither detected nor repaired.) The IRT was replaced on 2/22/2007.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

TWP/GNDRAD/C2 - Reprocess: IRT calibration

The configuration of the IRT was set to that used at TWP/C3. This caused the calibration 
of the data to be wrong. It was corrected by reconfiguring the IRT to match the datalogger 
program.
   
These data can be reprocessed and corrected by adding 10K, i.e. sfc_ir_temp(new) = 
sfc_ir_temp(old) + 10K.

• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)

TWP/GNDRAD/C2 - Reprocessed: Incorrect calibration

The Gndrad PSP was changed out 11/25 but the datalogger program was not updated until 
11/30.

PSP #31293 installed 20071125.2202.  Correct calibration coefficient = 123.46.

Reprocessed to correct upwelling shortwave hemispheric irradiance (US) by:
US(new) = (US(old) / 123.56 ) * 123.46

Reprocessing completed March 2008.

• up_short_hemisp_std
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)

• inst_up_short_hemisp

TWP/SKYRAD/C2 - Reprocessed: Incorrect calibrations

The SKYRAD PSPs were changed out 11/25 but the datalogger program was not updated until 
11/30.

Reprocessed to correct calibration per:
  down_short_diffuse(corrected) = down_short_diffuse(orig) * (118.18/112.42)
  short_direct_normal(corrected)= short_direct_normal(orig) * (122.20/118.11)
  down_short_hemips(corrected) = down_short_hemisp(orig) * (133.16/137.57)

Reprocessing completed March 2008.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• short_direct_normal_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_short_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)

• inst_diffuse
• inst_direct_normal
• inst_global

TWP/SKYRAD/C2 - Direct Normal reading too low

The NIP (direct_normal shortwave irradiance) measurement was reading too low during this 
time period.  No TWP Ops documentation could be found to determine the cause but data 
review indicate that the NIP appeared to be reading low by about 25W/m2 during this period.  
The NIP data had well defined steps in irradiance when compared to three component checks 
indicating the problem period.

• Raw data stream - documentation not supported

• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• short_direct_normal_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal

TWP/SKYRAD/C2 - Tracker failure

Tracker failed to wake up on 12/17.  Ops reset tracker on 12/21.  

The affected instruments are the 8-48 (down_short_diffuse) and NIP (direct_normal) 
shortwave instruments.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_short_diffuse_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal
• inst_diffuse

TWP/SKYRAD/C2 - Tracker inoperative

The tracker failed in park position.  Tracker was replaced 5/14 but did not resume fully 
normal operation until 5/18.

The down_short_diffuse and short_direct_normal data are directly affected by this failure. 
 These data are not recoverable.

• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_short_diffuse_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

• inst_direct_normal
• inst_diffuse

TWP/SKYRAD/C2 - Instrument grounding problem

During this time period the IRT analog output line appears to have adversely affected the 
skyrad datalogger grounding.  This resulted in intermittent anomalous readings across all 
skyrad datalogger channels including logger voltage.

• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• down_long_hemisp1_min
• inst_down_long_hemisp2_tp
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp2_std
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• sky_ir_temp_min
• down_short_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• inst_down_long_hemisp1_dome_temp
• short_direct_normal_std
• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• sky_ir_temp_max
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• inst_down_long_hemisp1_case_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)

• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_sky_ir_signal
• inst_down_long_hemisp2_dome_resist
• inst_global
• inst_down_long_hemisp1_dome_resist

TWP/SKYRAD/C2 - IRT Missing

After a significant rain event on 5/25, the IRT was found to be the cause of grounding 
problems with the SKYRAD datalogger that was affecting the measurements from other 
instruments. This problem was solved by removing the IRT signal from the datalogger. The problem 
was suspected to be with either the power/signal cable or the internal grounding of the 
IRT. The problem was corrected when both the IRT and analog cable were replaced on 6/23.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

• inst_sky_ir_signal

TWP/GNDRAD/C2 - IRT missing

The 24 VDC power supply for the IRT failed.  IRT data are missing and unrecoverable.

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

TWP/SKYRAD/C2 - Reprocess: IRT configuration

When the IRT was replaced, it was not initially configured correctly.  The data will be 
reprocessed.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_min

TWP/GNDRAD/C2 - IRT power failure

The DC-DC power converter failed and was replaced.

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

• inst_sfc_ir_signal

TWP/QCRAD/C2 - Instrument grounding problem

A grounding problem with the skyrad data logger (discussed in DQR D090605.2) created 
intermittent anomalous voltages and incorrect data. Days listed in this DQR are periods where 
bad data could be clearly identified; data from other days in this date range should be 
treated with caution.

• Irradiance, longwave, downwelling, hemispheric(down_long_hemisp)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• LWdnTd
• LWdnTc
• LWupTd
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Best Estimate Global Downwelling Shortwave Hemispheric Irradiance(BestEstimate_down_short_hemisp)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• LWupTc

• LWupTc
• LWupTd
• Best Estimate Global Downwelling Shortwave Hemispheric Irradiance(BestEstimate_down_short_hemisp)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Irradiance, longwave, downwelling, hemispheric(down_long_hemisp)
• LWdnTd
• LWdnTc
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)

TWP/SWF/C2 - instrument grounding problem

A grounding problem with the skyrad data logger (discussed in DQR D090605.2) created 
intermittent anomalous voltages and incorrect flux data.  Measured all-sky fluxes and derived 
cloud fraction during these periods are incorrect. The identification of clear sky 
periods during these days and estimated clear sky fluxes may also be incorrect.  Days listed in 
this DQR are periods where bad data could be clearly identified; data from other days in 
this date range should be treated with caution.

• sswfluxdn_measured
• difratiodn_measured_stdev
• sswfluxdn_cloudeffect
• Measured Surface Albedo from Shortwave Irradiance Measurements (alb)(albedosw_measured)
• Measured Downwelling Global Shortwave Irradiance (gsw)(gswfluxdn_measured)
• Measured Downwelling Direct Shortwave Irradiance (dir)(dirfluxdn_measured)
• difcloudeffect_normalized
• difratiodn_measured
• difswfluxdn_cloudeffect
• gswfluxdn_cloudeffect
• Measured Downwelling Diffuse Shortwave Irradiance (dif)(difswfluxdn_measured)
• guvbdn_measured
• Fractional Sky Cover(cloudfraction)

• sswfluxdn_measured
• gswfluxdn_cloudeffect
• difswfluxdn_cloudeffect
• Measured Downwelling Global Shortwave Irradiance (gsw)(gswfluxdn_measured)
• Measured Surface Albedo from Shortwave Irradiance Measurements (alb)(albedosw_measured)
• sswfluxdn_cloudeffect
• Measured Downwelling Direct Shortwave Irradiance (dir)(dirfluxdn_measured)
• difratiodn_measured
• Measured Downwelling Diffuse Shortwave Irradiance (dif)(difswfluxdn_measured)
• guvbdn_measured

TWP/SKYRAD/C2 - Suspect PIR1 data

PIR1 was exhibiting unusual data excursions during the specified time ranges and data are 
suspect.  The problem spontaneously resolved on October 11th without site ops action.  
The problem has not returned.

• down_long_hemisp1_max
• down_long_hemisp1_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_dome_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_case_temp

• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp

TWP/SKYRAD/C2 - Tracker failure

Tracker failed on 6/16/2011. Ops replaced with a spare tracker. The affected instruments 
are the 8-48 (down_short_diffuse) and NIP (direct_normal) shortwave instruments.

The down_long_hemisp1 and 2 (PIR1 and PIR2) performance may have been affected by exposure 
to direct sun.

• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_long_hemisp1_min
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• inst_down_long_hemisp2_tp
• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp2_std
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• down_long_hemisp1_std
• inst_down_long_hemisp1_dome_temp
• short_direct_normal_std
• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• inst_down_long_hemisp1_case_temp

• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_down_long_hemisp2_dome_resist
• inst_down_long_hemisp1_dome_resist

TWP/SKYRAD/C2 - IRT power failure

The IRT measurements were incorrect due to a drop in the logger battery voltage.

• IR Brightness Temperature(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

• inst_sky_ir_signal