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)
• IR Brightness Temperature(ir_temp)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• (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 blac2body+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(bb31)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• MWR column precipitable water vapor(vap)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)

• Sky brightness temperature at 23.8 GHz(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 Teflon window(water_flag_fraction)
• 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 data points averaged for 23tbsky, 31tbsky, vap & liq(num_obs)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Standard deviation about the mean for the total water vapor amount(vap_sdev)

• MWR column precipitable water vapor(vap)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• IR Brightness Temperature(ir_temp)
• Sky brightness temperature at 23.8 GHz(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.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(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.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)

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.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(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/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)
• IR Brightness Temperature(ir_temp)
• Sky brightness temperature at 23.8 GHz(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)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Ambient temperature(tkair)
• Blackbody kinetic temperature(tkbb)
• lon(lon)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Dummy altitude for Zeb(alt)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Mixer kinetic (physical) temperature(tkxc)
• Averaged total liquid water along LOS path(liq)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• 31.4 GHz blackbody(bb31)
• base time(base_time)
• Time offset of tweaks from base_time(time_offset)
• (tknd)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• lat(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)
• Dummy altitude for Zeb(alt)
• 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 calibration curve offset(tbzenith31)
• 23.8 GHz noise diode calib adjusted to tknd_nom and low_pass filtered(expave23)
• IR Brightness Temperature(ir_temp)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• lon(lon)
• 23.8 GHz blackbody signal(tipbb23)
• 31.4 GHz sky signal(tipsky31)
• 31.4 GHz blackbody(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)
• (tknd)
• Time offset of tweaks from base_time(time_offset)
• 23.8 GHz Blackbody signal(bb23)
• (tair)
• 31.4 GHz goodness-of-fit coefficient(r31)
• 23.8 GHz noise diode calib (injection temp) at Tkxc(ndiode23)
• lat(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 calibration curve offset(tbzenith23)

• IR Brightness Temperature(ir_temp)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• lat(lat)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• base time(base_time)
• MWR column precipitable water vapor(vap)
• Time offset of tweaks from base_time(time_offset)
• lon(lon)
• Averaged total liquid water along LOS path(liq)
• Dummy altitude for Zeb(alt)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• (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)
• lon(lon)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Ambient temperature(tkair)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Dummy altitude for Zeb(alt)
• 31.4 GHz blackbody(bb31)
• lat(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 blac2body+noise injection signal(bbn31)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 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/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)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Temperature correction coefficient at 23.8 GHz(tc23)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Sky brightness temperature at 23.8 GHz(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/METTWR/C1 - Met Tower Data Incorrect During Calibrations/Changeouts

Met Tower Data was incorrect during this period while sensor changeouts and calibrations 
were accomplished.

• Minimum Dew Point Temperature(dew_pt_temp_min)
• Wind Speed out of range error(win_spd_out_of_range_error)
• Mean Dew Point Temperature(dew_pt_temp_mean)
• Dew Point Temperature out of range error(dew_pt_temp_out_of_range_error)
• Maximum Wind Direction(wind_dir_max)
• Relative humidity minimum(relh_min)
• Std Dev of Dew Point Temperature(dew_pt_temp_sd)
• Maximum Wind Speed(wind_spd_max)
• Std Dev of Wind Speed(wind_spd_sd)
• Std Dev of Air Temperature(temp_sd)
• Mean Relative Humidity(relh_mean)
• Temperature maximum(temp_max)
• Std Dev of Wind Direction(wind_dir_sd)
• Maximum Dew Point Temperature(dew_pt_temp_max)
• Dew Point Temperature Hardware Error(dew_pt_hardware_error)
• Mean Air Temperature or Hardware Error(temp_mean)
• Wind Direction out of range error(win_dir_out_of_range_error)
• Vector-averaged Wind Direction(wind_dir_vec_avg)
• Air Temperature Hardware Error(temp_hardware_error)
• Air Temperature out of range error(temp_out_of_range_error)
• Minimum Wind Speed(wind_spd_min)
• Minimum Wind Direction(wind_dir_min)
• Vapor Pressure out of range error(vap_pres_out_of_range_error)
• Minimum Vapor Pressure(vap_pres_min)
• Std Dev of Vapor Pressure(vap_pres_sd)
• Relative humidity maximum(relh_max)
• Maximum Vapor Pressure(vap_pres_max)
• Relative Humidity out of range error(relh_out_of_range_error)
• Mean Vapor Pressure(vap_pres_mean)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Temperature minimum(temp_min)
• Mean Wind Speed(wind_spd_mean)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)

• Relative Humidity out of range error(relh_out_of_range_error)
• Mean Relative Humidity(relh_mean)
• Air Temperature Hardware Error(temp_hardware_error)
• Mean Dew Point Temperature(dew_pt_temp_mean)
• Air Temperature out of range error(temp_out_of_range_error)
• Std Dev of Vapor Pressure(vap_pres_sd)
• Minimum Wind Direction(wind_dir_min)
• Wind Direction out of range error(wind_dir_out_of_range_error)
• Std Dev of Wind Direction(wind_dir_sd)
• Maximum Wind Direction(wind_dir_max)
• Maximum Wind Speed(wind_spd_max)
• Relative humidity maximum(relh_max)
• Minimum Vapor Pressure(vap_pres_min)
• Std Dev of Air Temperature(temp_sd)
• Temperature minimum(temp_min)
• Std Dev of Relative Humidity or Hardware Error Code(relh_sd)
• Mean Air Temperature or Hardware Error(temp_mean)
• Mean Vapor Pressure(vap_pres_mean)
• Std Dev of Dew Point Temperature(dew_pt_temp_sd)
• Wind Speed out of range error(wind_spd_out_of_range_error)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Temperature maximum(temp_max)
• Minimum Wind Speed(wind_spd_min)
• Maximum Dew Point Temperature(dew_pt_temp_max)
• Vector-averaged Wind Direction(wind_dir_vec_avg)
• Vapor Pressure out of range error(vap_pres_out_of_range_error)
• Std Dev of Wind Speed(wind_spd_sd)
• Mean Wind Speed(wind_spd_mean)
• Dew Point Temperature out of range error(dew_pt_temp_out_of_range_error)
• Dew Point Temperature Hardware Error(dew_pt_hardware_error)
• Minimum Dew Point Temperature(dew_pt_temp_min)
• Relative humidity minimum(relh_min)
• Maximum Vapor Pressure(vap_pres_max)

NSA/MWR/C1 - Reprocess: wrong calibration

Moisture was found inside the lens of the MWR. Removal of the moisture caused a 
significant change in the calibration, especially in the 23.8 GHz channel. The calibration was 
updated automatically.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)

NSA/METTWR/C1 - C1 SPURIOUS INFORMATION IN DATA HEADER

There is an attribute for read_timeout_count that should not be included.  
The affected prtion of the header is: read_timeout_count:details = '0 = no error, 1 = 
error'  
User should disregard this attribute information in the header.

• Number of timeouts reading the met tower data by height(read_timeout_count)

NSA/METTWR/C1 - C1 WIND SPEED DATA QUESTIONABLE

The anemometers located at all 4 levels (2m, 10m, 20m, and 40m) are heated anemometers.  
The thermistors controlling the amount of power applied to the cups of the anemometers 
failed.  This caused too much power to be sent to the heating elements.  The cups bubbled 
and, in some cases, completely melted through.

• Std Dev of Wind Speed(wind_spd_sd)
• Mean Wind Speed(wind_spd_mean)
• Minimum Wind Speed(wind_spd_min)
• Maximum Wind Speed(wind_spd_max)
• Vector-averaged Wind Speed(wind_spd_vec_avg)

• Mean Wind Speed(wind_spd_mean)
• Maximum Wind Speed(wind_spd_max)
• Std Dev of Wind Speed(wind_spd_sd)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Minimum Wind Speed(wind_spd_min)
• Wind Speed out of range error(wind_spd_out_of_range_error)

NSA/METTWR/C1 - C1 WIND DIRECTION DATA SUSPECT

The wind direction sensor at the 10m level and 20m level became frozen.  The senor at the 
10m level became frozen on July 25 2001.  The date that the 20m level became frozen is 
unknown but occurred after the 10m level became frozen.  Both sensors froze in such a way 
as to consistently report wind direction values out of the south.

• Wind Speed out of range error(win_spd_out_of_range_error)
• Std Dev of Wind Direction(wind_dir_sd)
• Wind Direction out of range error(win_dir_out_of_range_error)
• Vector-averaged Wind Direction(wind_dir_vec_avg)
• Minimum Wind Direction(wind_dir_min)
• Maximum Wind Direction(wind_dir_max)

• Wind Direction out of range error(wind_dir_out_of_range_error)
• Vector-averaged Wind Direction(wind_dir_vec_avg)
• Maximum Wind Direction(wind_dir_max)
• Std Dev of Wind Direction(wind_dir_sd)
• Minimum Wind Direction(wind_dir_min)

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.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(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.

• MWR column precipitable water vapor(vap)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(tbsky23)

• Sky brightness temperature at 23.8 GHz(tbsky23)
• MWR column precipitable water vapor(vap)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 31.4 GHz(tbsky31)

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)
• (tknd)