PYE/MWR/M1 - Reprocessed: Calibration corrected

On May 28 1:30 GMT the NFOV radiometer was placed in the field of view of the MWR tip 
calibration. Almost immediately calibration of the MWR was compromised resulting in incorrect 
brightness temperatures and overestimation of both PWV and LWP. 

On July 15 the NFOV radiometer was moved away from the MWR and the instantaneous 
calibration values jumped back to normal. The median values returned to normal on July 17 around 
2100.

The LOS data were reprocessed using interpolated values for the calibration coefficients.  
The reprocessed data are available from the ARM Archive effective December 7, 2005.  
NOTE: the format of the reprocessed data are slightly different than the format of the 
original data and the data available before and after the reprocessed data period.  The 
quality of the data are not affected, just the format.

The MWRTIP data can not be reprocessed and should be used with caution.

• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 23.8 GHz sky signal(tipsky23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 23.8 GHz(tc23)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Mean total liquid water amount along LOS path(liq)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean total water vapor amount along LOS path(vap)

PYE/MWRP/M1 - Bias in Ground Relative Humidity Measurement

On June 17 2005, the MWRP was re-installed at PYE after the Super Blower was replaced by 
the old style dew blower. The relative humidity ground sensor in the dew blower is not as 
accurate. This resulted in a negative relative humidity bias of about 5.9 %. In other 
words the MWRP sensor was underestimating the relative humidity. The bias was determined by 
comparing MWRP measurements with SMET and radiosonde measurements. The MP.cfg file for 
the MWRP was changed to reflect this bias on 09/02/2005 and will take effect on 09/03/2005 
0000 GMT

• Surface water vapor density at instrument(surfaceWaterVaporDensity)
• Surface relative humidity at instrument(surfaceRelativeHumidity)

• Raw data stream - documentation not supported(raw)

PYE/MWR/M1 - New software version (4.15) installed

A problem began with the installation of MWR.EXE version 4.12 in July 2002. The software 
had been upgraded from a "DOS" to a "Windows"-compiled program to address an earlier 
problem.  The software upgrade corrected the earlier problem but introduced a new one that 
caused line-of-sight observing cycles to be skipped, a 15% reduction in the number of tip 
curves, and saturation of CPU usage. Software versions 4.13 and 4.14 also produced these 
problems.

The new MWR software, version 4.15, was installed on 9/13/2005. As a consequence of this 
upgrade, the tip curve frequency increased. The tip cycle time decreased from ~60s to ~50s.

• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Blackbody kinetic temperature(tkbb)
• Ambient temperature(tkair)
• Noise diode mount temperature(tknd)
• 31.4 GHz Blackbody signal(bb31)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• 23.8 GHz sky signal(tipsky23)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz blackbody+noise injection signal(bbn31)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz Blackbody signal(bb31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Ambient temperature(tkair)
• 23.8 GHz Blackbody signal(bb23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Noise diode mount temperature(tknd)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean total water vapor amount along LOS path(vap)

PYE/SKYRAD/M1 - 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.

• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp_shaded2)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp_shaded1)

PYE/GNDRAD/M1 - Reprocessed: 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 have been reprocessed to 
remove the calibration bias.  The reprocessed 60 second averaged data are based on 3 
instantaneous 20 second data records rather than on 60 1 second instantaneous data records. 
Still, these data are considered far superior to the originally processed data. The 
reprocessed data were archived in February 2007.

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

PYE/SKYRAD/M1 - Datalogger program error affected downwelling longwave

The excitation delays used in measuring the PIR1 case thermistor, "Case1", and the PIR2 
dome thermistor, "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.

At Pt Reyes, we are unable to determine if the excitation delay problem was present.  The 
first Skyrad datalogger program installed at PYE was correct but later versions modified 
and uploaded in March and April of 2005 may have had the Delay0 problem.

The problem also can not be determined from the data.  Pt. Reyes temperature fluctuations 
throughout the year are maritime and fall into a relatively narrow range in 2005 between 
2.5-20C.  The Delay0 problem introduces larger errors into PIR1 and PIR2 irradiance 
calculations as the temperature drops.  At the lowest temperature at Pt Reyes in 2005 (approx 
2.5C occurring in March) the largest PIR1 error would be -.48 W/m2 and PIR2 +.38 W/m2.  
The scale of these errors are smaller than the resolution of the instrument and are lost 
in the normal variation of the instrument readings. Cursory review of the thermistor data 
during cold periods does not show any discernable biases.  Furthermore, the data logger 
programming "error" due to the Delay0 problem is an order of magnitude less than the total 
estimated measurement uncertainty of the pyrgeometer data from any ARM installation (+/- 
5 W/sq m for 4-coeff and +/- 10 W/sq m for 2-coeff calibrations).

Due to these issues, no Delay0 corrections will be applied to PYE Skyrad data.

• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2, Standard
  Deviation(down_long_hemisp_shaded2_std)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Shaded
  Pyrgeometer1(inst_down_long_shaded1_case_temp)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Shaded
  Pyrgeometer2(inst_down_long_shaded2_dome_temp)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp_shaded2)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp_shaded1)
• Instantaneous Downwelling Pyrgeometer Thermopile, Shaded Pyrgeometer2(inst_down_long_hemisp_shaded2_tp)
• Instantaneous Downwelling Pyrgeometer Thermopile, Shaded Pyrgeometer1(inst_down_long_hemisp_shaded1_tp)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Shaded
  Pyrgeometer1(inst_down_long_shaded1_dome_temp)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1, Minima(down_long_hemisp_shaded1_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1, Standard
  Deviation(down_long_hemisp_shaded1_std)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Shaded
  Pyrgeometer2(inst_down_long_shaded2_case_temp)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2, Minima(down_long_hemisp_shaded2_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1, Maxima(down_long_hemisp_shaded1_max)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2, Maxima(down_long_hemisp_shaded2_max)

• Instantaneous Downwelling Pyrgeometer Dome Thermistor Resistance, Shaded
  Pyrgeometer1(inst_down_long_shaded1_dome_resist)
• Instantaneous Downwelling Pyrgeometer Dome Thermistor Resistance, Shaded
  Pyrgeometer2(inst_down_long_shaded2_dome_resist)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Resistance, Shaded
  Pyrgeometer1(inst_down_long_shaded1_case_resist)
• Instantaneous Downwelling Pyrgeometer Case Thermistor Resistance, Shaded
  Pyrgeometer2(inst_down_long_shaded2_case_resist)
• Instantaneous Downwelling Pyrgeometer Thermopile, Shaded Pyrgeometer1(inst_down_long_hemisp_shaded1_tp)
• Instantaneous Downwelling Pyrgeometer Thermopile, Shaded Pyrgeometer2(inst_down_long_hemisp_shaded2_tp)