TWP/SMET/C3 - Lower wind direction sensor misaligned

The lower wind direction sensor (sensor #2) was misaligned and off by 15 degrees.

• wind2_dir_sd
• Wind #2 direction vector average(wind2_dir_vec_avg)

• lo_dir_sd
• lo_dir_vec_avg

TWP/SMET/C3 - Intermittent Pressure Sensor Failure

The Barometric Pressure sensor was intermittently failing at TWP site C3 Darwin.  At times 
there were large pressure fluctuations occurring on the order of 24 mb in a few minutes. 
 Times of large pressure fluctuations are readily apparent in the data.  At these times 
the data should be carefully analyzed before determining it's usefulness.  In between the 
periods of large fluctuations the readings appear to be stable.  It is still suggested 
that independent pressure data be obtained for comparison before use.

• Atmospheric pressure(atmos_pressure)

• Atmospheric pressure(atmos_pressure)

TWP/SKYRAD/C3 - Reprocess: PIR identified as unshaded is really shaded

From the initial installation of the Darwin SKYRAD suite of instruments, two shaded PIRs 
were installed rather than one shaded and one unshaded PIR as 
documented in the netcdf header information.

• inst_down_long_hemisp2_dome_temp
• down_long_hemisp2_min
• down_long_hemisp2_max
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• inst_down_long_hemisp2_case_temp
• down_long_hemisp2_std
• inst_down_long_hemisp2_tp

TWP/SKYRAD/C3  - IRT incorrect min/delta values

For field sky_ir_temp, the value of valid_min was incorrectly assigned to -49.7 C and no 
value of valid_delta was assigned. The actual values should be -60 and 50 C, respectively.

• sky_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)

TWP/SMET/C3 - Data reported at 15sec rather than 60s intervals

Data in these data streams should be reported at 60sec intervals, but
the logger program running during this time had the interval set to
15s.  Users will have to average the 15sec data to get 60sec data.

• Wind #1 speed arithmetic average(wind1_spd_arith_avg)
• Wind #2 speed maximum gust(wind2_spd_max_gust)
• Wind #2 speed maximum(wind2_spd_max)
• wind2_spd_sd
• Wind #1 speed maximum gust(wind1_spd_max_gust)
• Precipitation mean(precip_mean)
• time_offset
• vappress_sd
• Wind #1 speed minimum(wind1_spd_min)
• wind1_dir_sd
• Temperature maximum(temp_max)
• logger_temp
• wind2_dir_sd
• Wind #2 speed vector average(wind2_spd_vec_avg)
• internal_voltage
• bit_data
• Wind #2 speed minimum(wind2_spd_min)
• Precipitation maximum(precip_max)
• Wind #1 speed vector average(wind1_spd_vec_avg)
• Atmospheric pressure(atmos_pressure)
• Relative humidity maximum(relh_max)
• Relative humidity minimum(relh_min)
• Vapor pressure mean(vappress_mean)
• temp_sd
• Temperature minimum(temp_min)
• relh_sd
• Wind #1 direction vector average(wind1_dir_vec_avg)
• external_voltage
• Precipitation minimum(precip_min)
• Temperature mean(temp_mean)
• Wind #2 direction vector average(wind2_dir_vec_avg)
• Wind #2 speed arithmetic average(wind2_spd_arith_avg)
• wind1_spd_sd
• Relative humidity mean(relh_mean)
• precip_sd
• Wind #1 speed maximum(wind1_spd_max)

• lo_dir_sd
• Vapor pressure mean(vappress_mean)
• logger_temp
• up_spd_max
• up_spd_min
• precip_sd
• lo_spd_min
• temp_sd
• relh_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• lo_dir_vec_avg
• up_spd_sd
• lo_spd_arith_avg
• tbrg_total
• Temperature mean(temp_mean)
• Precipitation mean(precip_mean)
• up_dir_vec_avg
• tbrg_count_total
• time_offset
• Relative humidity mean(relh_mean)
• lo_spd_vec_avg
• lo_spd_sd
• Atmospheric pressure(atmos_pressure)
• up_spd_arith_avg
• lo_spd_max
• vappress_sd
• up_spd_vec_avg
• up_dir_sd
• time
• internal_voltage

TWP/GNDRAD/C3 - IRT bias

The IRT behaved erratically, jumping frequently from reporting about 50 Wm^(-2) higher 
than the PIR for surface irradiance values to about 100Wm^(-2) lower than the PIR.  
Generally, the IRT measured lower surface temperatures than expected from the PIR.

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

TWP/SMET/C3 - Rain blocked pressure port

Atmospheric pressure values were suspect due to anomolous readings during heavy rain 
events.  Suspect blockage of port due to rainfall.  New logger and enclosure corrected problem.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C3 - Negative rainfall rates

Due to limitations of the Zeno dataloggers all voltage measurements
from the optical rain gauge (ORG) were converted to rainfall rates. 
This resulted in negative values for rain rates.  Any value below
0.10 mm/hr should be considered to be 0 mm/hr.  New dataloggers 
alleviated this problem.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SKYRAD/C3 - 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.

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

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

TWP/SKYRAD/C3 - 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.

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

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

TWP/SKYRAD/C3 - Incorrect NIP cal coefficient

During our site visit comparison at Darwin we observed that the skyrad NIP was reading 
about 50 w/m2 lower than the comparison cavity radfiometer and the replacement NIP on the 
comparison stand. We found that the calibration coefficient for the NIP (responsivity at 
45o)was put in as 8.64X10-6. The NIP was new and had not been calibrated at SGP. The 
factory number was 8.04X10-6. We corrected the calibration coefficient and the instruments 
agreed to better than 5 w/m2.

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

TWP/SKYRAD/C3 - Reprocess: NIP calibrations incorrect

On 05/20 during installtion of the new Campbell datalogger system and associated program 
the NIP (S/N 33551E6) was assigned an incorrect calibration coefficient.  A coefficient of 
116.01 W/m2/mV was applied when it should have been 124.378 W/m2/mV.
TWP reports SV0405D and SV0409D detail the activities which lead to this DQR.

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

• Raw data stream - documentation not supported

TWP/SMET/C3 - Data non-representative

Tower mast was lowered for inspection.  Data during this time is non-representative.

• lo_dir_sd
• tbrg_count_total
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• up_spd_max
• up_spd_min
• lo_spd_sd
• lo_spd_vec_avg
• precip_sd
• lo_spd_min
• Atmospheric pressure(atmos_pressure)
• temp_sd
• up_spd_arith_avg
• lo_spd_max
• vappress_sd
• relh_sd
• up_spd_vec_avg
• up_dir_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• up_spd_sd
• lo_dir_vec_avg
• lo_spd_arith_avg
• tbrg_total
• Temperature mean(temp_mean)
• Precipitation mean(precip_mean)
• up_dir_vec_avg

TWP/GNDRAD/C3 - IRT bias

The IRT measured higher surface temperatures than expected from the PIR, even at night.

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

TWP/GNDRAD/C3 - Reprocess: IRT with wrong calibration

A spare IRT was installed that was not configured properly.

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

TWP/SMET/C3 - Lower wind direction sensor failure

The lower wind direction sensor failed on 4/14 and disagrees significantly with the upper 
wind direction sensor.  The lower wind sensor reports a constant value around 0-15 
degrees since it failed.  Testing showed that excitation channel two on the logger was the 
problem.  Logger was replaced by spare.

• lo_dir_sd
• lo_dir_vec_avg

TWP/SMET/C3 - Data not representative

Tower was lowered for radiometer change and characterization. Data are not representative 
of local conditions.

• lo_dir_sd
• tbrg_count_total
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• up_spd_max
• up_spd_min
• lo_spd_sd
• lo_spd_vec_avg
• precip_sd
• lo_spd_min
• Atmospheric pressure(atmos_pressure)
• temp_sd
• up_spd_arith_avg
• lo_spd_max
• vappress_sd
• relh_sd
• up_spd_vec_avg
• up_dir_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• up_spd_sd
• lo_dir_vec_avg
• lo_spd_arith_avg
• tbrg_total
• Temperature mean(temp_mean)
• Precipitation mean(precip_mean)
• up_dir_vec_avg

TWP/GNDRAD/C3 - Tower inverted for instrument testing and replacement

The tower at Darwin was brought down to test and replace the Gndrad PIR on 8/5/2005 and 
the PSP on 8/9/2005

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

TWP/SKYRAD/C3 - tracker inoperative

A lightning strike at Darwin removed the tracker from service.  Instruments installed on 
the tracker were rendered either inoperative or were not shaded during this time period.  
The longwave hemispheric instruments PIR1 and PIR2 appear to have been unaffected.  They 
are not suseptable to incorrect tracker operation.  The downwelling hemispheric shortwave 
PSP instrument mounted on Skyrad will not be affected by incorrect tracker operation.

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

• inst_direct_normal
• inst_diffuse

• Raw data stream - documentation not supported

TWP/SMET/C3 - Upper wind sensor failure

A lightning strike destroyed the upper wind sensor.

• up_spd_vec_avg
• up_dir_sd
• up_spd_max
• up_spd_min
• up_spd_sd
• up_spd_arith_avg
• up_dir_vec_avg

TWP/SMET/C3 - RH Values Artificially High

Lightning strike caused RH readings to be higher than reasonable (130%).

• relh_sd
• Vapor pressure mean(vappress_mean)
• vappress_sd
• Relative humidity mean(relh_mean)

TWP/SMET/C3 - Instrument failure

A lightning strike caused a failure in the ORG.  Rainfall was being continually recorded.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SKYRAD/C3 - 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 errors are inversely proportial to temperature.

Users can apply temperature dependent irradiance corrections as 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_shaded2_max
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• down_long_hemisp_shaded1_max
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded2_std
• down_long_hemisp_shaded2_min
• down_long_hemisp_shaded1_min

TWP/GNDRAD/C3 - IRT malfunction

The internal IRT power supply failed (probably due to a lightning strike on 11/14) and was 
drawing excessive current on the data logger's DC system. The problem was corrected by 
replacing the instrument with a spare.

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

TWP/SKYRAD/C3 - IRT damaged

The analog output of the IRT was damaged by a lightning strike. The problem was corrected 
by replacing the instrument with a spare. The damaged IRT was returned to the vendor for 
repair.

• sky_ir_temp_min
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std

• inst_sky_ir_signal

TWP/GNDRAD/C3 - IRT power

The IRT failed to report after a planned power outage to add lightning protection modules 
to the AC power wiring. The problem was corrected when a loose power connection to the 
logger was found, rectified, and power restored to the logger.

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

TWP/SKYRAD/C3 - Tracker stopped

Solar Tracker stopped and had to be repowered

• down_long_hemisp_shaded2_max
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer(down_long_hemisp_unshaded)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Minima(down_long_hemisp_unshaded_min)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_short_diffuse_hemisp_std
• Downwelling Longwave Hemispheric Irradiance, Unshaded Pyrgeometer, Maxima(down_long_hemisp_unshaded_max)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_long_hemisp_shaded2_std
• down_long_hemisp_shaded2_min
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• down_long_hemisp_shaded1_max
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_long_hemisp_shaded1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp_unshaded_std
• down_long_hemisp_shaded1_min
• down_long_hemisp_shaded_std

TWP/SKYRAD/C3 - Solar Tracker locking at solar noon

The Scitech solar tracker from SGP that was installed on 2005-12-01 after the previous 
tracker was damaged by lightning on 2005-11-14 has been hanging up every day at solar noon.  
In Feb, the sun moved from south to north and the Scitech tracker does not seem to be 
able to deal with this. During this period the operators power cycled the tracker between 
05:00Z and 10:00Z almost every day and data from around solar noon (03:30Z) until the 
power cycle are unusable for the measurements that use the tracker (NIP, B&W Diffuse, and 
shaded PIRs).
The problem was corrected when the Scitech tracker was replaced by a Brusag
tracker on 2006-03-10.

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_long_hemisp_shaded2_max
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer1(down_long_hemisp_shaded1)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• down_long_hemisp_shaded2_std
• down_long_hemisp_shaded2_min
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• down_short_hemisp_std
• down_long_hemisp_shaded1_min
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• down_long_hemisp_shaded1_max
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp_shaded1_std
• down_long_hemisp_shaded_std

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

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

• Raw data stream - documentation not supported

TWP/SMET/C3 - ORG data noisy due to degraded ground

SMET Rain Data began to be noisy during December 2005 and the problem slowly became worse 
over time so that in February 2006 the ORG was reporting with a constant background value 
of around 0.10 mm/hr rain rate.  ORG voltage showed a near constant value above the 85mV 
threshold.  The ground for the ORG had become degraded and was lost due to corrosion.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Reprocessed: Lower windspeed sensor calibration error

The lower anemometer was replaced but the calibration coefficients were not changed during 
this period.  The data were reprocessed to apply the correct calibrations and the 
reprocessed data were archived in August 2008.

• lo_spd_vec_avg
• lo_spd_sd
• lo_spd_min
• lo_spd_arith_avg
• lo_spd_max

TWP/GNDRAD/C3 - IRT failed

The IRT began to fail on 4/7/2006 and failed completely (apparently due to the internal 
power supply) on 4/27. It was replaced on 5/18.

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

TWP/SMET/C3 - Data not representative

The Anemometer readings were incorrect due to the tower being lowered for maintenance.

• lo_spd_sd
• lo_spd_vec_avg
• lo_spd_min
• lo_dir_sd
• up_spd_arith_avg
• lo_spd_max
• up_spd_vec_avg
• up_dir_sd
• up_spd_max
• up_spd_sd
• up_spd_min
• lo_dir_vec_avg
• lo_spd_arith_avg
• up_dir_vec_avg

TWP/SKYRAD/C3 - 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 pyrgeometer1(down_long_hemisp_shaded1)
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer2(down_long_hemisp_shaded2)

TWP/GNDRAD/C3 - 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/SMET/C3 - Reprocess: Barometric pressure units change

Barometric pressure data during this time period is reported in hPa.  After this time, the 
data have been converted to kPa to standardize the measurement units among ARM sites and 
to conform to accepted standard units determined by the scientific community.

• Atmospheric pressure(atmos_pressure)

TWP/GNDRAD/C3 - IRT bias

The IRT reported higher surface temperatures than the PIR due to corrosion on the 
terminals of the lightning protection module and a ground wire error. The corrosion was cleaned 
and the wiring corrected.

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

TWP/SMET/C3 - Reprocess: Tipping bucket rain gauge added

A tipping bucket rain gauge was added to the SMET suite of instruments effective 20060926. 
 Two new variables (count and rain amount) were added at the end of the twpsmet60sC1.b1 
datastream.  When reprocessing of this datastream occurs these variables will be added 
with -9999 (missing) as the value for dates prior to gauge installation.

• base_time

TWP/SKYRAD/C3 - NIP Failure

Skyrad normal incident shortwave irradiance (NIP) started reporting impossible values for 
direct normal irradiance starting 16 November approx 2100GMT corresponding to a rain 
event at the same time.

The NIP was replaced fixing the problem.

Direct normal data are not recoverable.  However, the NIP data can be calculated from the 
global hemsipherical shortwave and global hemispherical diffuse datastreams by using the 
following relationship:
Global Horizontal = Direct Normal x cos(Z) + Diffuse Horizontal 
where Z is the zenith angle.

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

• inst_direct_normal

TWP/SKYRAD/C3 - NIP instrument failure

The NIP (Short Direct Normal) was replaced after it displayed symptoms of failure 
associated with either unknown precipitation related issues or a possible lightning strike.

NIP data are not recoverable.  Direct normal data can be reconstructed from global 
hemispheric and global diffuse data using the following relationship:
   global hemispheric = direct*cos(sza) + diffuse hemispheric

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

• inst_direct_normal

• Raw data stream - documentation not supported

TWP/RAIN/C3 - faulty precipitation result from blocked funnel

The funnel was partially blocked and the water was flowing so slowly through the system 
that the timing of precipitation was wrong.

• Rainfall rate(rain_rate)
• Precipitation(precip_tbrg)

TWP/SMET/C3 - Barometer Data Incorrect

The barometer data was incorrect or missing due to water intrusion.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C3 - Water in enclosure

Data became erratic and unreasonable after water intrusion into the enclosure.

• relh_sd
• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• temp_sd
• Vapor pressure mean(vappress_mean)
• Precipitation mean(precip_mean)
• Temperature mean(temp_mean)
• vappress_sd
• Relative humidity mean(relh_mean)

TWP/SMET/C3 - Upper wind speed artificially slow

The upper wind measurement was consistently slower by around 0.5 - 1 m/s than the lower 
wind measurement.  The bearings on the upper wind measurement were binding.

• up_spd_vec_avg
• up_spd_max
• up_spd_min
• up_spd_sd
• up_spd_arith_avg

TWP/GNDRAD/C3 - Maintenance activities affected GNDRAD

While maintenance was performed on the SMET anenometer, the GNDRAD instruments were 
inverted. Disregard GNDRAD data during this time.

• inst_up_long_dome_resist
• inst_sfc_ir_signal
• inst_up_short_hemisp
• lat
• lon
• base_time
• time
• alt
• inst_up_long_hemisp_tp
• inst_up_long_case_resist
• time_offset

• net_min
• net_std
• up_long_hemisp_std
• time_offset
• external_voltage
• lat
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• lon
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• logger_temp
• base_time
• net
• sfc_ir_temp_std
• net_max
• alt
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• bit_data
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• internal_voltage
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)

TWP/SMET/C3 - ORG overestimated rainfall

Optical rain gauge (ORG) measured approximately 10mm higher than two co-located tipping 
bucket rain gauges and a co-located disdrometer.  The ORG is typically higher but usually 
not by an order of magnitude.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/GNDRAD/C3 - Gndrad shutdown for tropical cylone

On Jan 3rd approximately 1000GMT the effects of a tropical cyclone started affecting the 
installed radiometer measurements at ARM/TWP/C3(Darwin) - both Skyrad and Gndrad.  On Jan 
4th 0740 GMT the Gndrad station was shutdown to avoid damage due to the close passing of 
this storm.  Station was restarted Jan 7th 0515GMT.

• time_offset
• alt
• lat
• inst_up_long_case_resist
• inst_up_long_hemisp_tp
• lon
• base_time
• inst_up_long_dome_resist

• inst_sfc_ir_signal
• inst_up_short_hemisp
• lat
• lon
• base_time
• time
• alt
• inst_up_long_hemisp_tp
• time_offset

• up_long_hemisp_std
• time_offset
• lat
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• lon
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• logger_temp
• base_time
• sfc_ir_temp_std
• alt
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)

• Raw data stream - documentation not supported

TWP/SMET/C3 - Upper Wind Sensor Data Questionable

The wind_up vs. wind_low wind directions diverged, with the differences between the two 
eventually reached 45 degrees. The Upper sensor was found to be mis-aligned and loose.

• up_spd_vec_avg
• up_spd_max
• up_spd_min
• up_spd_sd
• up_spd_arith_avg

TWP/SKYRAD/C3 - IRT power supply

The 12-to-24V DC converter the provides power to the IRT had shut down and was restarted 
by power-cycling.

• sky_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std

TWP/SMET/C3 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we
continuously collect data even when no rain is occurring.  We also capture small events 
such as leaves, large bugs, dust, etc blowing through the measurement path.  Because this 
discrete event occurs quickly the value is usually captured for 1 or 2 seconds.  This 
value is then averaged to the minute producing rainrate on the order of .009 mm/hr or less.  

These values are not indicative of rain and should be removed from the record or summing 
over long periods can bias the climate record.  We will reprocess the data to remove these 
small values.

• precip_sd
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• Precipitation mean(precip_mean)

TWP/SMET/C3 - Lower Wind Direction Intermittently Wrong

The lower wind sensor cabling had a problem causing an intermittent connection for the 
wind direction data.

• lo_dir_sd
• lo_dir_vec_avg

TWP/SMET/C3 - Upper wind speed data incorrect

Beginning on 07/08, the upper wind sensor started reporting significantly lower wind 
speeds than the lower wind sensor.  The cable connections weather proofing failed allowing 
corrosion to occur and increasing he resistance of the cables.  This in turn lowered the 
wind speeds artificially.

• up_spd_vec_avg
• up_spd_max
• up_spd_min
• up_spd_sd
• up_spd_arith_avg

TWP/SKYRAD/C3 - Contamination

The IRT exhibited a positive bias compared to AERI. The problem was corrected when the 
lens and mirror were cleaned.

• sky_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std

TWP/SMET/C3 - Missing data

Data are missing and unrecoverable.

• alt
• lo_dir_sd
• lon
• base_time
• tbrg_count_total
• time_offset
• Vapor pressure mean(vappress_mean)
• Relative humidity mean(relh_mean)
• logger_temp
• up_spd_max
• up_spd_min
• lo_spd_vec_avg
• lo_spd_sd
• precip_sd
• lo_spd_min
• Atmospheric pressure(atmos_pressure)
• temp_sd
• lat
• up_spd_arith_avg
• lo_spd_max
• vappress_sd
• up_spd_vec_avg
• relh_sd
• up_dir_sd
• time
• Precipitation maximum(precip_max)
• Precipitation minimum(precip_min)
• internal_voltage
• lo_dir_vec_avg
• up_spd_sd
• lo_spd_arith_avg
• tbrg_total
• Temperature mean(temp_mean)
• Precipitation mean(precip_mean)
• up_dir_vec_avg

TWP/SMET/C3 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• up_spd_vec_avg
• lo_spd_vec_avg
• lo_spd_sd
• lo_spd_min
• up_spd_max
• up_spd_min
• up_spd_sd
• lo_spd_arith_avg
• up_spd_arith_avg
• lo_spd_max

TWP/SKYRAD/C3 - Direct normal instrument failure

The NIP instrument (short_direct_normal data stream) failed giving bad data during this 
time period.  The failure start time coincides with a reported DC power failure but no 
connection between the reported power failure and the failure of this instrument could be 
determined. 

Ops also reported the tracker clock running 2.9 minutes slow during maintenance on 12/22 
0300GMT (see CS-2008-0714).  Again, the slow clock is not suspect and did not appear to 
affect alignment.

Ops replaced the NIP instrument on 12/30 and short_direct_normal data resumed normal 
operation.

Disregard the short_direct_normal (NIP) data during this time period or calculate using 
the global and diffuse instruments and the following relationship:
short_direct_normal = ((down_short_hemisp - down_short_diffuse_hemisp))/cos(zenith angle)

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

• inst_direct_normal

TWP/SKYRAD/C3 - Tracker inoperative

The tracker at Darwin failed 01/23.  The tracker was power cycled on 01/27 and it returned 
to normal operation.

The affected data streams are short_direct_normal (NIP) and down_short_diffuse_hemisp 
(8-48).  

The down_short_hemisp are not affected.  

The down_long_hemisp1 and 2 (PIR1 and PIR2) should not be affected but direct sun can 
affect individual instrument performance.

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

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

TWP/SMET/C3 - Reprocess: Station Pressure values reported in hPa instead of kPa.

An incorrect program was entered into the datalogger.  This program did not convert the 
station pressure from hPa to kPa.  This made the values larger by a factor of 10 and caused 
the QC bit to be tripped.

• Atmospheric pressure(atmos_pressure)

TWP/SMET/C3 - Reprocess: Temperature data biased low

Due to a datalogger problem, the temperature data were biased low by 2.13 degrees C.

The data will be reprocessed.

• temp_sd
• Temperature mean(temp_mean)

TWP/SMET/C3 - Reprocess: Temperature Biased low by 1.06 Degrees

The temperature of the SMET system was biased low by 1.06 Deg C due to a non-precision 
resistor being used int he measurement circuit.  The data will be reprocessed.  Saturation 
Vapor pressure and Vapor pressure will have to be reprocessed also.

Add 1.06 degrees to the temperature data.  

Correct Sat Vap Press using the Buck approximation:
   Es = 6.1121exp((17.502*T)/(240.97 + T) 
where T is the temperature in C.  

Correct Vapor pressure using: E = (RH*Es)/100

• temp_sd
• Vapor pressure mean(vappress_mean)
• Temperature mean(temp_mean)
• vappress_sd

TWP/SMET/C3 - Tower Lowered for Maintenance

The tower was lowered for annual anemometer changes.  The wind data is suspect.

• lo_spd_sd
• lo_spd_vec_avg
• lo_spd_min
• lo_dir_sd
• up_spd_arith_avg
• lo_spd_max
• up_spd_vec_avg
• up_dir_sd
• up_spd_max
• up_spd_sd
• up_spd_min
• lo_dir_vec_avg
• lo_spd_arith_avg
• up_dir_vec_avg

TWP/SKYRAD/C3 - IRT power supply

The IRT external DC power supply had shut down for an unknown reason. The problem was 
corrected by restarting the power supply.

• sky_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std

TWP/SKYRAD/C3 - IRT power supply

The IRT power supply failed and was replaced.

• sky_ir_temp_min
• sky_ir_temp_max
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std