NSA/MWR/C1 - Temperature Stabilization of Noise Diode Impaired

On 1/17 we had a big spike in the data and lost temperature stabilization. The instrument 
had problems maintaining the Noise Diode (ND) temperature since. At ambient temperatures 
under about -20 C the ND was not maintaining the set temperature of 30 C. This problem 
was reported in P010122.1.

Fred Solheim recommended on 1/22 that we powercycle the instrument as it looked like the 
instrument CPU had lost the temperature reference.

So we powercycled the instrument on 1/22 @ 20:30 and lost all comumnication to it; after a 
second powercycling the instrument came back on line and the temperature stabilized 
quickly (within a couple of minutes) to the set temperature (30 C)

Fred Solheim reported after the system was restored:
"I've never seen this behavior before. I don't think it was due to the RF deck physically 
hanging temperature, because the recorded temp dropped about 30 C in one observation 
cycle. If this happens again, send the MWR down along with data files for us to look at."

Data collected in the periode 1/17/2001 6:00 to 1/22/2001 21:45 are questionable since it 
is uncertain whether the temperature really was unstable and what really caused the 
problem.

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Noise diode mount temperature(tknd)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz sky signal(sky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• 31.4 GHz Blackbody signal(bb31)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Mean total water vapor amount along LOS path(vap)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Standard deviation about the mean for the IR brightness temperature(ir_temp_sdev)
• Number of points included in the ir_temp ensemble(num_obs_irt)
• Standard deviation about the mean for the 23.8 GHz sky brightness temperature(tbsky23_sdev)
• Fraction of data in averaging interval with water on the Teflon window(water_flag_fraction)
• Mean IR brightness temperature(ir_temp)
• Standard deviation about the mean for the 31.4 GHz sky brightness temperature(tbsky31_sdev)
• Standard deviation about the mean for the total liquid water amount(liq_sdev)
• Number of points included in the ensemble of all the fields except the ir_temp
  fields(num_obs)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)

• Mean total water vapor amount along LOS path(vap)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

NSA/MWR/C1 - negative sky brightness temperatures

The data exhibit occasional negative sky brightness temperatures.
The problem was corrected when the site operator cleaned the cable connectors and coated 
the terminals with dielectric grease.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

NSA/MWR/C1 - negative sky brightness temperatures

The data exhibit occasional negative sky brightness temperatures.
The problem was corrected when the computer was reconfigured following a virus infection.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

NSA/MWR/C2 - Reprocess: calibration change

The thicker (1/2-inch) insulation was installed on the RF deck and the reference 
temperature was reduced from 50 C to 30 C to prevent thermal instability in winter. A change in 
the mixer temperature affects the instrument's calibration. A new calibration was 
automatically derived and applied after 1500 valid tip curves were acquired. During the period 
after the temperature was reset and before the calibration was updated, the previous 
calibration was used.

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)

• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz sky signal(tipsky23)

NSA/MWR/C1 - Reprocess: calibration change

The thicker (1/2-inch) insulation was installed on the RF deck and the reference 
temperature was reduced from 50 C to 30 C to prevent thermal instability in winter. A change in 
the mixer temperature affects the instrument's calibration. A new calibration was 
automatically derived and applied after 1500 valid tip curves were acquired. During the period 
after the temperature was reset and before the calibration was updated, the previous 
calibration was used.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

NSA/MWR/C1 - incorrect flagging of data

The wet window flag is set high more than expected.

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

NSA/MWR/C1 - incorrect flagging of data

The wet window flag is set high more frequent than expected.

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

NSA/MWR/C2 - incorrect flagging of data

The wet window flag is set high more frequent than expected.

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

• Water on Teflon window (1=WET, 0=DRY)(wet_window)

NSA/MWR/C1 - NSA Barrow MWR down due to PC Virus

On 12/22 at 23:00 the PC communication hung. Before operators returned to work after the 
holidays on 12/26, the virus W32.kriz triggered on 12/25 at 1:43 GMT. This virus wiped out 
large amount of files, hereunder the data files from the period 12/22 23:00 - 12/25 
01:00 and OS system files. The fixed PC was re-installed on 1/5, due issues with using serial 
ports under DOS comunication with instrument was not restored until 1/9 @ 22:30 GMT

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz sky signal(sky31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• east longitude for all the input platforms.(lon)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• altitude above sea levelaltunits(alt)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• Mean total liquid water amount along LOS path(liq)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz Blackbody signal(bb31)
• Time offset from base_time(base_time)
• Time offset of tweaks from base_time(time_offset)
• Noise diode mount temperature(tknd)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• north latitude for all the input platforms.(lat)
• 23.8 GHz Blackbody signal(bb23)

• Blackbody temperature 1(tkbb1)
• 31.4 GHz noise diode calib (injection temp) at Tkxc(ndiode31)
• 31.4 GHz calibration curve slope(gain31)
• altitude above sea levelaltunits(alt)
• Time offset from base_time(base_time)
• 31.4 GHz noise diode calib adjusted to tknd_nom and low_pass filtered(expave31)
• Actual elevation angle(actel)
• Tip configuration number(tipn)
• 23.8 GHz goodness-of-fit coefficient(r23)
• 31.4 GHz zenith brightness temperature(tbzenith31)
• 23.8 GHz noise diode calib adjusted to tknd_nom and low_pass filtered(expave23)
• Mean IR brightness temperature(ir_temp)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• east longitude for all the input platforms.(lon)
• 23.8 GHz blackbody signal(tipbb23)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz Blackbody signal(bb31)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal+noise injection signal(tipskynd31)
• Blackbody temperature 2(tkbb2)
• 23.8 GHz calibration curve slope(gain23)
• Actual Azimuth(actaz)
• Noise diode mount temperature(tknd)
• Time offset of tweaks from base_time(time_offset)
• 23.8 GHz Blackbody signal(bb23)
• Air temperature at blower inlet(tair)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz noise diode calib (injection temp) at Tkxc(ndiode23)
• north latitude for all the input platforms.(lat)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz blackbody signal(tipbb31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz sky signal+noise injection signal(tipskynd23)
• Mixer kinetic (physical) temperature(tkxc)
• Airmass value(airm)
• 23.8 GHz zenith brightness temperature(tbzenith23)

• Mean IR brightness temperature(ir_temp)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• north latitude for all the input platforms.(lat)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Time offset from base_time(base_time)
• Mean total water vapor amount along LOS path(vap)
• Time offset of tweaks from base_time(time_offset)
• east longitude for all the input platforms.(lon)
• Mean total liquid water amount along LOS path(liq)
• altitude above sea levelaltunits(alt)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Noise diode mount temperature(tknd)
• 23.8 GHz sky signal(tipsky23)
• Actual elevation angle(actel)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Actual Azimuth(actaz)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• east longitude for all the input platforms.(lon)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Ambient temperature(tkair)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• altitude above sea levelaltunits(alt)
• 31.4 GHz Blackbody signal(bb31)
• north latitude for all the input platforms.(lat)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)
• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Time offset from base_time(base_time)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Time offset of tweaks from base_time(time_offset)
• 23.8 GHz Blackbody signal(bb23)
• Blackbody kinetic temperature(tkbb)

NSA/MWR/C2 - elevated sky brightness temperatures

The MWR was providing unreasonable values of sky brightness temperatures 
and values of precipitable water vapor and liquid water path that were
about 10 times larger than expected. The problem was corrected when the 
instrument was power-cycled. The cause of the problem is unknown.

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)

• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz sky signal(tipsky23)

NSA/MWR/C1 - Reprocess: calibration change

The computer was replaced but not configured correctly for the MWR.

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

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(tipsky23)
• 31.4 GHz sky signal(tipsky31)

NSA/MWR/C2 - elevated sky brightness temperatures

The MWR was providing unreasonable values of sky brightness temperatures. 
The problem was corrected when the instrument was power-cycled. The cause 
of the problem is unknown.

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)

• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz sky signal(tipsky23)

NSA/MWR/C1 - Contamination or Calibration Effect

A short period of odd data occurs in PWV and the LWP.  Its a sudden offset in the data 
values.  Vic Morris suggests it could be a calibration issue as seen before at SGP.  Data 
make a marked change after the events (suggesting the data were questionable prior to this 
time).  No obvious changes in other instruments occur. Some of these effects may coincide 
with operator's preventive maintenance but others are in the middle of the night local 
time and can not be explained by cleaning.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

NSA/MWR/C1 - Frosting

Spike in PWV and LWP
. Operator reports instrument is frosted. Instrument teflon window was cleaned by 
operator.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

NSA/MWR/C1 - Instrument maintenance

Installed cold weather insulation on radiometer, required time to thermally stabilize.

• 23.8 GHz sky plus noise injection signal(skyn23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz sky signal(sky31)
• 31.4 GHz Blackbody signal(bb31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean total water vapor amount along LOS path(vap)
• 31.4 GHz sky+noise injection signal(skyn31)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• Noise diode mount temperature(tknd)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz noise injection brightness temperature(unoise31)
• 23.8 GHz noise injection brightness temperature(unoise23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Which LOS configuration(losn)
• Air temperature at blower inlet(tair)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)

• 31.4 GHz Blackbody signal(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise diode mount temperature(tknd)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Blackbody kinetic temperature(tkbb)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 31.4 GHz sky signal(sky31)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• 23.8 GHz sky signal(sky23)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Temperature correction coefficient at 23.8 GHz(tc23)

NSA/MWR/C1 - MWR moved

The MWR data are unreasonable during this period, because it was shutdown and moved by 
operations at this time.

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky plus noise injection signal(skyn23)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz sky signal(sky31)
• 31.4 GHz Blackbody signal(bb31)
• Time offset from base_time(base_time)
• Mean total water vapor amount along LOS path(vap)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz sky+noise injection signal(skyn31)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Time offset of tweaks from base_time(time_offset)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• Noise diode mount temperature(tknd)
• Actual Azimuth(actaz)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• 31.4 GHz noise injection brightness temperature(unoise31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz noise injection brightness temperature(unoise23)
• Actual elevation angle(actel)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• east longitude for all the input platforms.(lon)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Which LOS configuration(losn)
• Air temperature at blower inlet(tair)
• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)

• Actual elevation angle(actel)
• Actual Azimuth(actaz)
• 31.4 GHz Blackbody signal(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• north latitude for all the input platforms.(lat)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Noise diode mount temperature(tknd)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Time offset from base_time(base_time)
• Blackbody kinetic temperature(tkbb)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Time offset of tweaks from base_time(time_offset)
• 31.4 GHz sky signal(sky31)
• east longitude for all the input platforms.(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• altitude above sea levelaltunits(alt)
• 23.8 GHz sky signal(sky23)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Temperature correction coefficient at 23.8 GHz(tc23)

NSA/MWR/C1 - negative PWV (bad calibration?)

During this time, the PWV drops to slightly negative values.  This could be related to 
calibration issues.

• Mean total water vapor amount along LOS path(vap)

• Mean total water vapor amount along LOS path(vap)

NSA/MWR/C1 - Heater/blower removed

Note that the heater/blower was removed from the MWR during this time.  This may impact 
snow removal from teflon window, thereby affecting the quality of the data between 
cleanings.

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky plus noise injection signal(skyn23)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Noise diode mount temperature(tknd)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz noise injection brightness temperature(unoise31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 23.8 GHz noise injection brightness temperature(unoise23)
• 31.4 GHz sky signal(sky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Mean total water vapor amount along LOS path(vap)
• 31.4 GHz sky+noise injection signal(skyn31)
• Which LOS configuration(losn)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Air temperature at blower inlet(tair)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• Mixer kinetic (physical) temperature(tkxc)

• Blackbody kinetic temperature(tkbb)
• Mean total water vapor amount along LOS path(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• 31.4 GHz sky signal(sky31)
• Sky/Cloud Infra-Red Temperature(sky_ir_temp)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise diode mount temperature(tknd)
• 23.8 GHz sky signal(sky23)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Temperature correction coefficient at 23.8 GHz(tc23)

NSA/MWR/C1 - Data spikes, possibly due to cleaning events

Unreasonable spikes occurred, which may be due to cleaning of 
the instrument by the operator.  Other cleaning events did
not result in obvious data spikes and have not been included 
in this report.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

SGP/MWR/C1 - Intermittent Negative Sky Brightness Temperatures

Several related and recurring problems with the MWRs have been reported
dating back to 1999.  These problems were due to the occurrence of
blackbody signals (in counts) that were half of those expected. The
symptoms included noisy data, spikes in the data, negative brightness
temperatures, and apparent loss of serial communication between the
computer and the radiometer, which results in a self-termination of the
MWR program.

Because these all initially appeared to be hardware-related problems,
the instrument mentor and site operations personnel (1) repeatedly
cleaned and replaced the fiber optic comm. components, (2) swapped
radiometers, (3) sent radiometers back to Radiometrics for evaluation
(which did not revealed any instrument problems), and (4) reconfigured
the computer's operating system.  Despite several attempts to isolate
and correct it, the problem persisted.

It became apparent that some component of the Windows98 configuration
conflicted with the DOS-based MWR program or affected the serial port
or the contents of the serial port buffer. This problem was finally
corrected by upgrading the MWR software with a new Windows-compatible
program.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

NSA/MWR/C2 - Intermittent Negative Sky Brightness Temperatures

Several related and recurring problems with the MWRs have been reported
dating back to 1999.  These problems were due to the occurrence of
blackbody signals (in counts) that were half of those expected. The
symptoms included noisy data, spikes in the data, negative brightness
temperatures, and apparent loss of serial communication between the
computer and the radiometer, which results in a self-termination of the
MWR program.

Because these all initially appeared to be hardware-related problems,
the instrument mentor and site operations personnel (1) repeatedly
cleaned and replaced the fiber optic comm. components, (2) swapped
radiometers, (3) sent radiometers back to Radiometrics for evaluation
(which did not revealed any instrument problems), and (4) reconfigured
the computer's operating system.  Despite several attempts to isolate
and correct it, the problem persisted.

It became apparent that some component of the Windows98 configuration
conflicted with the DOS-based MWR program or affected the serial port
or the contents of the serial port buffer. This problem was finally
corrected by upgrading the MWR software with a new Windows-compatible
program.

• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total liquid water amount along LOS path(liq)
• Mean total water vapor amount along LOS path(vap)

NSA/MWR/C1 - min/max/delta values incorrect

The values of valid_min, valid_max, and valid_delta for fields tkxc and tknd were 
incorrect. They should be 303, 333, and 0.5 K, respectively.

• Mixer kinetic (physical) temperature(tkxc)
• Noise diode mount temperature(tknd)

NSA/MWR/C2  - min/max/delta values incorrect

The values of valid_min, valid_max, and valid_delta for fields tkxc and tknd were 
incorrect. They should be 303, 333, and 0.5 K, respectively.

• Mixer kinetic (physical) temperature(tkxc)
• Noise diode mount temperature(tknd)

NSA/MWR/C1 - software upgrade (version 3.28)

The MWR operating program was upgraded to version 3.28 on 3 February 1999. This version 
includes a beam width correction as well as providing the capability to automatically level 
the elevation mirror (that is, to automatically detect and correct offsets in the 
elevation angle stepper motor position.)

The improvement in the quality of the tip curves resulting from the auto-
leveling has been dramatic: differences in the brightness temperatures at
3 airmasses (19.5 and 160.5 degrees) have been reduced from +/- 5 K to
+/- 0.5 K.  In order to take full advantage of this improvement to detect and reject 
cloudy tip curves, the minimum value of the goodness-of-fit coefficient for a valid tip curve 
has been increased from 0.995 to 0.998.

• Mean total water vapor amount along LOS path(vap)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)

• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)

NSA/MWR/C1 - Software Change

The MWR operating software was changed on 16 November 1998 to provide additional 
functionality as described below. This change affects the format of the raw and ingested data. 
   
NEW FEATURES
1. Faster sampling rate
   
Standard line-of-sight (LOS) observations can now be acquired at 15-second intervals vs. 
20-second intervals previously. (The standard LOS cycle is comprised of one sky sample per 
blackbody sample and gain update.)
   
2. More flexible sampling strategy
   
Multiple sky observations can be acquired during a LOS cycle, up to 1024 per gain update. 
This permits sky samples to be acquired at intervals of 2.67 seconds for improved 
temporal resolution of cloud liquid water variations and better coordination with the millimeter 
cloud radar during IOPs.
   
3. Separation of zenith LOS observations from TIP data
   
When the radiometer is in TIP mode, the zenith LOS observations are now extracted, the PWV 
and LWP computed and reported separately in the output file. This eliminates the periods 
of missing LOS data during calibration checks/updates.
   
4. Automatic self-calibration
   
The software now permits the calibration to be updated at specified intervals or 
continuously. In the first case, LOS mode is automatically changed to TIP mode at user-specified 
intervals or whenever clear sky conditions occur, the tip data reduced, the calibration 
updated, and the radiometer returned to LOS mode without operator intervention. In the 
second case, the radiometer is continuously is TIP mode until changed by the operator.
   
5. Graphical user display
   
The graphical display is comprised of a status display, a message display, a temperature 
plot, a plot of the retrieved PWV and LWP, and (in TIP mode) a plot of the latest tip 
curves.

• Ambient temperature(tkair)
• Noise diode mount temperature(tknd)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)

• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise diode mount temperature(tknd)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Ambient temperature(tkair)

• Noise injection temp at 31.4 GHz derived from this tip(tnd31I)
• Noise diode mount temperature(tknd)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Ambient temperature(tkair)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Noise injection temp at 23.8 GHz derived from this tip(tnd23I)

NSA/MWR/C1 - Spikes in PWV data

The PWV data began exhibiting a pattern of large (~5 cm) spikes which exponetially degrade 
to normal values. The problem is due to a fault in the serial or fiber optic data 
communication. This pattern began intermittent occurrence on 4/9/98 but it dominates the data 
by 5/1/98.

• Mean total water vapor amount along LOS path(vap)

• Mean total water vapor amount along LOS path(vap)

NSA/MWR/C1 - Spikes in PWV data

After reinstallation of repaired MWR #20, PWV data began exhibiting a pattern of large (~5 
cm) spikes which exponetially degrade to normal values. The problem was due to a fault 
in the serial or fiber optic data communication.

This pattern began intermittant ocurrance on 8/15/98 but it dominates the data by 9/6/98.

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

• Mean total water vapor amount along LOS path(vap)
• Mean total liquid water amount along LOS path(liq)

NSA/MWR/C1 - Reprocess: incorrect calibrations

MWR #17 was placed in service while MWR #20 was being repaired by the manufacturer.  The 
data need to be reprocessed with calibration coefficients appropriate for this instrument.

• Raw data stream - documentation not supported(Raw data stream - documentation not supported)

• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• 23.8 GHz sky signal(sky23)
• Mean IR brightness temperature(ir_temp)
• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Noise diode mount temperature(tknd)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz blackbody+noise injection signal(bbn31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• 31.4 GHz sky signal(sky31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• 31.4 GHz Blackbody signal(bb31)
• Blackbody kinetic temperature(tkbb)
• east longitude for all the input platforms.(lon)
• Time offset from base_time(base_time)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Mean total water vapor amount along LOS path(vap)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• Time offset of tweaks from base_time(time_offset)
• altitude above sea levelaltunits(alt)
• north latitude for all the input platforms.(lat)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)

• Mean total water vapor amount along LOS path(vap)
• Time offset of tweaks from base_time(time_offset)
• north latitude for all the input platforms.(lat)
• east longitude for all the input platforms.(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Mean total liquid water amount along LOS path(liq)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• altitude above sea levelaltunits(alt)
• Mean IR brightness temperature(ir_temp)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Time offset from base_time(base_time)