PYE/SKYRAD/M1 - Reprocessed: IRT configuration and calibration

The configuration of the IRT was inadvertently set to default and the program of the data 
loggers were changed to that used at TWP.C3.  This caused the calibration of the data to 
be wrong. It was corrected by reconfiguring the IRT and changing the conversion factors 
in the data logger program.

These data have been reprocessed to apply correct calibrations and the reprocessed data 
were archived in February, 2007.

• Sky Infra Red Temperature Minima(sky_ir_temp_min)
• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Standard Deviation of Sky Infra Red Temperature(sky_ir_temp_std)
• Sky Infra-Red Temperature(sky_ir_temp)

• null(Raw data stream - documentation not supported)

• Instantaneous Sky/Cloud Infrared(inst_sky_ir_signal)

PYE/MWR/M1 - Instrument computer locked up

The MWR computer locked up and required a reboot at 00Z on June 9, 2005.  When the program 
was restarted, water vapor, liquid path, and temps dropped to zero.  They did not 
recover until 15Z the same day.

• (tknd)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Averaged total liquid water along LOS path(liq)
• Blackbody kinetic temperature(tkbb)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Ambient temperature(tkair)
• MWR column precipitable water vapor(vap)

PYE/MWR/M1 - Reprocessed: Revised Retrieval Coefficients

IN THE BEGINNING (June 1992), the retrieval coefficients used to derive the precipitable 
water vapor (PWV) and liquid water path (LWP) from the MWR brightness temperatures were 
based on the Liebe and Layton (1987) water vapor and oxygen absorption model and the Grant 
(1957) liquid water absorption model.

Following the SHEBA experience, revised retrievals based on the more recent Rosenkranz 
(1998) water vapor and oxygen absorption models and the Liebe (1991) liquid water absorption 
model were developed. The Rosenkranz water vapor absorption model resulted a 2 percent 
increase in PWV relative to the earlier Liebe and Layton model.	The Liebe liquid water 
absorption model decreased the LWP by 10% relative to the Grant model. However, the 
increased oxygen absorption caused a 0.02-0.03 mm (20-30 g/m2) reduction in LWP, which was 
particularly significant for low LWP conditions (i.e. thin clouds encountered at SHEBA).

Recently, it has been shown (Liljegren, Boukabara, Cady-Pereira, and Clough, TGARS v. 43, 
pp 1102-1108, 2005) that the half-width of the 22 GHz water vapor line from the HITRAN 
compilation, which is 5 percent smaller than the Liebe and Dillon (1969) half-width used in 
Rosenkranz (1998), provided a better fit to the microwave brightness temperature 
measurements at 5 frequencies in the range 22-30 GHz, and yielded more accurate retrievals. 
Accordingly, revised MWR retrieval coefficients have been developed using MONORTM, which 
utilizes the HITRAN compilation for its spectroscopic parameters.  These new retrievals 
provide 3 percent less PWV and 2.6 percent greater LWP than the previous retrievals based on 
Rosenkranz (1998).

At Point Reyes, the original coefficients implemented in March 2005 were based on a 
version of the Rosenkranz model that had been modified to use the HITRAN half-width at 22 GHz 
and to be consistent with the water vapor continuum in MONORTM.  These retrievals yielded 
nearly identical results to the MONORTM retrievals.

The MONORTM-based retrieval coefficients became active at PYE.M1 20050506.

Note: The PYE.M1 MWRLOS data for 20050201-20050506 have been reprocessed
to apply the MONORTM-based retrievals for all time. The reprocessed data
were archived in April 2007.  The TIP data have not been reprocessed.

• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)

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)
• Averaged total liquid water along LOS path(liq)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• MWR column precipitable water vapor(vap)

PYE/SKYRAD/M1 - IRT bias

The SKYRAD IRT measured lower sky temperatures than the AERI.  This may have been due to a 
dirty mirror or lens.

• Sky Infra Red Temperature Minima(sky_ir_temp_min)
• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Standard Deviation of Sky Infra Red Temperature(sky_ir_temp_std)
• Sky Infra-Red Temperature(sky_ir_temp)

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)
• (tknd)
• 31.4 GHz blackbody(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 blac2body+noise injection signal(bbn31)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz blackbody(bb31)
• Sky brightness temperature at 23.8 GHz(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)
• (tknd)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Sky Infra-Red Temperature(sky_ir_temp)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• MWR column precipitable water vapor(vap)

PYE/GNDRAD/M1 - Reprocessed: IRT configuration and calibration

The configuration of the IRT was inadvertently set to default and the program of the data 
loggers were changed to that used at TWP.C3.  This caused the calibration of the data to 
be wrong. It was corrected by reconfiguring the IRT and changing the conversion factors 
in the data logger program.

These data have been reprocessed to apply correct calibrations and the reprocessed data 
were archived 20070212.

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

• Instantaneous Surface Infra-Red Signal(inst_sfc_ir_signal)

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, Pyrgeometer(up_long_hemisp)