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)
• IR Brightness Temperature(ir_temp)
• Averaged total liquid water along LOS path(liq)
• Sky brightness temperature at 23.8 GHz(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(bb31)
• base time(base_time)
• MWR column precipitable water vapor(vap)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz sky+noise injection signal(skyn31)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Time offset of tweaks from base_time(time_offset)
• Sky Infra-Red Temperature(sky_ir_temp)
• (tknd)
• Actual Azimuth(actaz)
• 31.4 GHz blac2body+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)
• lon(lon)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Which LOS configuration(losn)
• (tair)
• Dummy altitude for Zeb(alt)
• lat(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(bb31)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• lat(lat)
• Sky Infra-Red Temperature(sky_ir_temp)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• (tknd)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• IR Brightness Temperature(ir_temp)
• Ambient temperature(tkair)
• Temperature correction coefficient at 31.4 GHz(tc31)
• base time(base_time)
• Blackbody kinetic temperature(tkbb)
• MWR column precipitable water vapor(vap)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• Time offset of tweaks from base_time(time_offset)
• 31.4 GHz sky signal(sky31)
• lon(lon)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Averaged total liquid water along LOS path(liq)
• Mixer kinetic (physical) temperature(tkxc)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Dummy altitude for Zeb(alt)
• 23.8 GHz sky signal(sky23)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Temperature correction coefficient at 23.8 GHz(tc23)

NSA/SKYRAD/C1 - Unshaded PIR data unreasonable

Periods of very large negative values. 
Negative readings of thermistors caused concurrent calculation 
in logger of temperature to fail.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Shaded PIR data unreasonable

Periods of very large negative values. 
Negative readings of thermistors causes concurrent calculation 
in logger of temperature to fail.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Shaded PIR data unreasonable

There was  a 10-25 W/m2 spike in data probably due to operator working around instrument 
or cleaning it.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - PIR data suspect

The PIR unshaded and the PIR shaded have a persistent offset between them, ranging from 0 
to 10 W/m2. It is particularly apparent during clear sky. The line of sight of the PIRd 
is obstructed making it difficult to assess the problem. The instrument was moved to its 
proper location in early February. The problem seems to have resolved itself with the move.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR shaded maximum(pirs_max)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR shaded standard deviation(pirs_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Shaded PIR data incorrect

There were two sudden increases (about 50-100 W/m2) at 23:00 and 24:00.

• PIR shaded maximum(pirs_max)
• PIR shaded standard deviation(pirs_sd)
• PIR shaded minimum(pirs_min)
• PIR shaded mean(pirs_mean)

NSA/SKYRAD/C1 - Spikes in Unshaded PIR data

There was  a 10-25 W/m2 spike in data probably due to operator working around instrument 
or cleaning it.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/SKYRAD/C1 - Discontinuity in Unshaded PIR data

There was a sudden increase in irradiance (from 140 to 190 W/m2) at 02/03/99 23:00.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded minimum(pir1_min)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)

NSA/GNDRAD/C1 - Noisy PIR Data

During the period referenced, the ground PIR was noisy in comparison to the sky PIR data.  
At the end of November, the noise increased to roughly 10 W/m2 from peak to peak.  After 
12/23/98, the noise decreased in amplitude but still had noisy patterns.  

On 01/17-18/99, there was an increase again in the noise level (4 GMT 01/17 - 5 GMT 
01/18). During this period the gndrad IRT data also exhibited noise patterns (the IRT was not 
operational).

In February, the instrument exhibited large noise variations again.  On 02/16, a wiring 
problem was corrected and the noise dropped back to 1-5 W/m2.  However, the noise levels 
began to increase again.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - PIR offline

The PIR was taken off line during this period; data recorded 
              during this period are garbage.

• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded mean(pir1_mean)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded minimum(pir1_min)

NSA/GNDRAD/C1 - Bad PSP calibrations applied

The ground radiation data are bad during this period due to 
              erroneous calibration factors in the logger configuration file.

• PSP1 unshaded maximum(psp1_max)
• NET mean(net_mean)
• PIR1 unshaded standard deviation(pir1_sd)
• PIR1 unshaded maximum(pir1_max)
• PIR1 unshaded mean(pir1_mean)
• Net Radiation, Minima(net_min)
• PIR1 unshaded minimum(pir1_min)
• Net Radiation(net)
• NET standard deviation(net_sd)
• Net Radiation, Standard Deviation(net_std)
• PSP1 unshaded mean(psp1_mean)
• PSP1 unshaded minimum(psp1_min)
• Net Radiation, Maxima(net_max)
• PSP1 unshaded standard deviation(psp1_sd)

NSA/C1/MWR - liquid water paths affected by frost and ice formation

The heater/blower did not completely remove ice and frost formed on the 
teflon window under severe winter weather conditions. Also, the sensitivity
of the moisture sensor was temperature dependent and, if the temperature 
changd significantly after the sensor had been tuned, the heater failed to 
turn on when the window became wet or frosted. This resulted in unflagged 
periods of elevated and unrealistic values of liquid water path.

The heater/blower assembly was replaced with an improved version that 
incorporates better circuitry, a larger capacity fan, and better airflow 
distribution.

• MWR column precipitable water vapor(vap)
• Water on Teflon window (1=WET, 0=DRY)(wet_window)
• Averaged total liquid water along LOS path(liq)

NSA/SKYRAD/C1 - IRT measurements during precipitation events

The IRT measurement of sky/cloud temperature was in question during precipitation events 
because rain or snow could accumulate in the upward-pointed lens barrel. This was 
corrected by reorienting the IRT to measure the sky temperature as reflected by a gold mirror.

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

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.

• 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/GNDRAD/C1 - IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C.  Measurements of sky temperature were over-estimated when instrument was below 
freezing.

• IRT1 standard deviation(irt1_sd)
• IRT1 mean(irt1_mean)
• IRT1 maximum(irt1_max)
• IRT1 minimum(irt1_min)

NSA/SKYRAD/C1 - IRT insufficiently heated

IRT had insufficient heating to maintain an internal reference temperature above 0 degrees 
C. Measurements of sky temperature were over-estimated when instrument was below 
freezing.

• IRT1 maximum(irt1_max)
• IRT1 standard deviation(irt1_sd)
• IRT1 minimum(irt1_min)
• IRT1 mean(irt1_mean)