NIM/MET/M1 - Software problem

Intermittent Failure of Logger to read data from the Barometer.

• Barometric Pressure(atmos_pressure)

NIM/TSI/M1 - Reprocess: Data processing problem

Due to the high aerosol conditions at Niamey, the TSI appeared to be beyond the limits of 
processing the color JPEG image into cloud fraction values. Several attempts to adjust 
the sky filter values used to process the images did not yielded the desired results. The 
processed images indicate an opaque sky cover, even in the absence of clouds.

The problem was corrected by removing the neutral density filter from the lens and 
re-adjusting the sky filter values.

The data can be reprocessed.

• PNG data stream - documentation not supported(png)

• Pixel count: number total opaque(count.opaque)
• Pixel count: number opaque in sun circle(region.sun.count.opaque)
• Pixel count: number thin in horizon area(region.horizon.count.thin)
• Sunshine meter(sunny)
• Pixel count: number opaque in zenith circle(region.zenith.count.opaque)
• Pixel count: number opaque in horizon area(region.horizon.count.opaque)
• Pixel count: number thin in zenith circle(region.zenith.count.thin)
• Pixel count: number thin in sun circle(region.sun.count.thin)
• Percent opaque cloud(percent.opaque)
• Pixel count: number total thin(count.thin)
• Percentage thin cloud(percent.thin)

NIM/MWR/M1 - Instrument noise problem/RF interference

Data are affected by intermittent spikes that become more frequent starting in March 2006. 
Spikes affect data mostly around 9 AM and 18:00 PM. The origin of the spikes is probably 
RF interference.

• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• 31.4 GHz sky signal(tipsky31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz sky signal(tipsky23)

• null(Raw data stream - documentation not supported)

• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)
• 31.4 GHz sky signal(sky31)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• 23.8 GHz sky signal(sky23)

NIM/MET/M1  - Optical Rain Gauge Failure

The optical rain gauge on the met system did not record precipitation during this time 
period.

• Precipitation rate minimum(precip_rate_min)
• Precipitation rate mean(precip_rate_mean)
• Precipitation rate maximum(precip_rate_max)
• Precipitation rate standard deviation(precip_rate_sd)

NIM/MWR/M1 - Reprocessed: Recalibration to correct for occasional overheating.

The radiometer was intermittently thermally unstable resulting in poor calibrations for 
four brief time periods.  These data have been reprocessed to apply corrected calibrations. 
 The affected time periods were:

20060302-20060303
20060423-20060425
20060512-20060515
20060531-20060603

• 23.8 GHz blackbody+noise injection signal(bbn23)
• 31.4 GHz blackbody(bb31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• 31.4 GHz goodness-of-fit coefficient(r31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• (tknd)
• Mixer kinetic (physical) temperature(tkxc)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz sky brightness temperature derived from tip curve(tbsky31tip)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz sky brightness temperature derived from tip curve(tbsky23tip)
• 31.4 GHz sky signal(tipsky31)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Temperature correction coefficient at 31.4 GHz(tc31)
• 23.8 GHz goodness-of-fit coefficient(r23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)
• Total liquid water along zenith path using tip-derived brightness temperatures(liqtip)
• Blackbody kinetic temperature(tkbb)
• Total water vapor along zenith path using tip-derived brightness temperatures(vaptip)
• 23.8 GHz sky signal(tipsky23)

• Mixer kinetic (physical) temperature(tkxc)
• 31.4 GHz blackbody(bb31)
• Sky brightness temperature at 23.8 GHz(tbsky23)
• 23.8 GHz blackbody+noise injection signal(bbn23)
• 23.8 GHz sky signal(sky23)
• Blackbody kinetic temperature(tkbb)
• Noise injection temp at nominal temperature at 23.8 GHz(tnd_nom23)
• Noise injection temp at 31.4 GHz adjusted to tkbb(tnd31)
• Temperature correction coefficient at 31.4 GHz(tc31)
• Averaged total liquid water along LOS path(liq)
• MWR column precipitable water vapor(vap)
• (tknd)
• 31.4 GHz blac2body+noise injection signal(bbn31)
• 23.8 GHz Blackbody signal(bb23)
• 31.4 GHz sky signal(sky31)
• Sky brightness temperature at 31.4 GHz(tbsky31)
• Noise injection temp at nominal temperature at 31.4 GHz(tnd_nom31)
• Temperature correction coefficient at 23.8 GHz(tc23)
• Noise injection temp at 23.8 GHz adjusted to tkbb(tnd23)

NIM/MWR/M1 - Sun in field of view of radiometer

Around 12 pm every day between 8/1 and 8/31 there is an increase in the brightness 
temperature due to the sun being in the field of view of the radiometer.

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

NIM/SKYRAD/M1 - Tracker inoperative

Starting on 9/12 the NIM radiometer tracker drifted enough due to sinking supports and a 
drifting clock that the direct normal measurments (NIP) and the downwelling hemispheric 
diffuse shortwave measurments (8-48) were adversely affected in the afternoon hours.  The 
shortwave hemispheric global instrument (PSP) and downelling hemispheric longwave shaded1 
and shaded2 (PIR) are unaffected by this problem. 

The tracker problem greatly affected direct measurements and affected the diffuse 
measurement to a lesser extent. There are no redundant measurements for these instruments.  
However, during this time range the data collected before local noon (aprox 1140GMT) for all 
shortwave Skyrad instruments appear to be good.

• Instantaneous Uncorrected Downwelling Shortwave Diffuse, Shaded Pyranometer
  Thermopile Voltage(inst_diffuse)
• Instantaneous Direct Normal Shortwave Irradiance, Pyheliometer Thermopile
  Voltage(inst_direct_normal)

• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Standard Deviation(down_short_diffuse_hemisp_std)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)
• Shortwave Direct Normal Irradiance, Pyrgeometer(short_direct_normal)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Minima(down_short_diffuse_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Maxima(short_direct_normal_max)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
  Maxima(down_short_diffuse_hemisp_max)

• null(Raw data stream - documentation not supported)

NIM/TSI/M1 - Shadowband glare

When the neutral density filter was removed from the lens, the reflection of the sun from 
the smooth shadowband strip became much brighter causing a glare in the image on clear 
days. To minimize this reflection, a rough surface (the "fuzzy" side of an adhesive velco 
strip) was placed along the length of the shadowband.

• Sunshine meter(sunny)
• Relative \'strength\' of direct sun(sun.strength)
• Pixel count: number total in sun circle(region.sun.count)

NIM/MET/M1 - ORG Data Incorrect

The ORG measured around 9cm of rain in a short period while other co-located sensors 
measured no precip.

Use the Present Weather Detector data instead or set the ORG rainfall to 0mm during this 
time period.

• Precipitation rate minimum(precip_rate_min)
• Precipitation rate mean(precip_rate_mean)
• Precipitation rate maximum(precip_rate_max)
• Precipitation rate standard deviation(precip_rate_sd)

NIM/MET/M1 - ORG Data Underestimated Precipitation

The ORG underestimated precipitation by about 38% during the entire NIM deployment.  No 
troubleshooting technique or replacement of gage was successful in correcting the problem.

• Precipitation rate minimum(precip_rate_min)
• ORG carrier mean(org_carrier_mean)
• Precipitation rate mean(precip_rate_mean)
• Precipitation rate maximum(precip_rate_max)
• Precipitation rate standard deviation(precip_rate_sd)

NIM/MET/M1 - Reprocess: ORG Data has very small rainrate values

The ORG data is collected via analog signal and not digital.  Therefore, we
   continuously collect data even when no rain is occurring.  We also capture
   small events such as leaves, large bugs, dust, etc blowing through the
   measurement path.  Because this discrete event occurs quickly the value is
   usually captured for 1 or 2 seconds.  This value is then averaged to the
   minute producing rainrate on the order of .009 mm/hr or less.  These values
   are not indicative of rain and should be removed from the record or summing
   over long periods can bias the climate record.  We are reprocessing the data
   to remove these small values and are adjusting the collection program to
   remove them before ingest.

• Precipitation rate minimum(precip_rate_min)
• Precipitation rate mean(precip_rate_mean)
• Precipitation rate maximum(precip_rate_max)
• Precipitation rate standard deviation(precip_rate_sd)

NIM/MET/M1 - Wind Speed data contain offset due to induced voltage

The marine model of the RM Young wind sensor needs twisted pair shielded cable.  The 
manufacturer did not originally supply the pigtail with twisted pair shielded cable.  Use of 
twisted pair shielded cable for the rest of the cable run to the logger was also not 
specified.  This caused an induced voltage in the wind speed line from the wind direction 
excitation.  The induced voltage varied from sensor to sensor and probably changed anytime 
the cable was replaced or parts of the wind sensor were repaired or replaced. The induced 
voltage has been seen to vary from 0.15 m/s to as much as 1.08 m/s.

• Wind speed arithmetic average(wind_spd_arith_avg)
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Wind speed arithmetic minimum(wind_spd_arith_min)
• Wind speed arithmetic maximum(wind_spd_arith_max)
• Wind speed arithmetic standard deviation(wind_spd_arith_sd)