NIM/MWRP/M1 - Software problem

The MWRP computer failed and it was cloned with a new Gx620. Soon after, the MWRP program 
started to crash and was intermittent. Data were lost on March 3, 4, 5. 
On March 7 the program was forcefully ended and restarted. This appears to have cleared 
the problem. The instrument has been running since.

• Raw data stream - documentation not supported(raw)

• Level of free convection pressure(levelFreeConvectionPres)
• east longitude for all the input platforms.(lon)
• Time offset of tweaks from base_time(time_offset)
• Time offset from midnight of date of file. For CO data, this is identical to
  time_offset and is included for compatibility.(time)
• Expected root-mean-square error in liquid water path retrieval(liquidWaterPathRmsError)
• Solar azimuth referenced to the Central Facility.(azimuth)
• Expected root-mean-square error in liquid water content retrieval(liquidWaterContentRmsError)
• Lifting condensation level pressure(liftingCondensationLevelPres)
• Retrieved cloud liquid water content(liquidWaterContent)
• Surface relative humidity at instrument(surfaceRelativeHumidity)
• altitude above sea levelaltunits(alt)
• Lifting condensation level(liftingCondensationLevel)
• Interpolated water vapor mixing ratio(waterVaporMixingRatio)
• Derived virtual temperature(virtualTemperature)
• Elevation angle of Beam 0(elevation)
• Convective available potential energy(cape)
• Surface air temperature for last 5 minutes of previous hour(temperature)
• Internal blackbody reference temperature(blackbodyTemperature)
• Zenith-pointing infrared temperature at 10um(infraredTemperature)
• Level of free convection(levelFreeConvection)
• Flag indicating moisture sensor status(wetWindowFlag)
• Cloud-base height, from Micropulse LIDAR or Belfort LIDAR ceilometer(cloudBaseHeight)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Microwave brightness temperature(brightnessTemperature)
• Equilibrium level(equilibriumLevel)
• Time offset from base_time(base_time)
• atmospheric pressure at mean sea level and at tropopause (NGM250 predicted)(pressure)
• Equilibrium level pressure(equilibriumLevelPres)
• Surface absolute temperature at instrument(surfaceTemperature)
• Surface water vapor density at instrument(surfaceWaterVaporDensity)
• Expected root-mean-square error in liquid water path retrieval using only 23.835
  and 30.0 GHz(liquidWaterPath2RmsError)
• Surface pressure at instrument(surfacePressure)
• Derived relative humidity(relativeHumidity)
• Height of bins above ground level for the temperature, retrieved water vapor,
  and pressure profile(height)
• Expected root-mean-square error in precipitable water retrieval(totalPrecipitableWaterRmsError)
• Expected root-mean-square error in water vapor density retrieval(waterVaporDensityRmsError)
• north latitude for all the input platforms.(lat)
• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Data quality flags(dataQualityFlags)
• Interpolated dewpoint temperature(dewpointTemperature)
• Frequency(frequency)
• Retrieved water vapor density(waterVaporDensity)
• Retrieved liquid water path(liquidWaterPath)
• Expected root-mean-square error in temperature retrieval(temperatureRmsError)
• Expected root-mean-square error in precipitable water retrieval using only
  23.835 and 30.0 GHz(totalPrecipitableWater2RmsError)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)

• Raw data stream - documentation not supported(raw)

NIM/SONDE/M1 - RH data incorrect.

RH% values oscillate between ambient values and 0%.  The 0% RH values are incorrect.

• Relative humidity scaled, by total column amount from MWR(rh)
• Surface dew point temperature(dp)

NIM/MWRP/M1 - Instrument noise problem

There are spikes and elevated noise in MWRP data. The origine of the spikes is RF 
interference from various sources.  All brightness temperatures are affected, but in particular 
the 5 K-band channels. LWP retrievals are noisy and affected by spikes as a result.

• Raw data stream - documentation not supported(raw)

• Retrieved cloud liquid water content(liquidWaterContent)
• Derived relative humidity(relativeHumidity)
• Derived virtual temperature(virtualTemperature)
• Interpolated water vapor mixing ratio(waterVaporMixingRatio)
• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Surface air temperature for last 5 minutes of previous hour(temperature)
• Retrieved water vapor density(waterVaporDensity)
• Interpolated dewpoint temperature(dewpointTemperature)
• Retrieved liquid water path(liquidWaterPath)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Microwave brightness temperature(brightnessTemperature)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)

• Raw data stream - documentation not supported(raw)

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.

• Mean total liquid water amount along LOS path(liq)
• Mean 23.8 GHz sky brightness temperature(tbsky23)
• Mean total water vapor amount along LOS path(vap)
• 31.4 GHz sky signal(sky31)
• Mean 31.4 GHz sky brightness temperature(tbsky31)
• 23.8 GHz sky signal(sky23)

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

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

NIM/MWRP/M1 - IRT Sensor Calibration

Discrepancies between the MWRP and Skyrad IRT were observed in January. The MWRP IRT 
readings were constantly higher than those of the skyrad IRT. Some changes were introduced to 
the MWRP IRT to address the problem (see DQR D060602.2). On May 3, the IRT mirror was 
replaced. After the change in the mirror, the MWRP IRT readings became about 5-8 C lower. On 
June 3 the agreement between MWRP and Skyrad IRT became satisfactory (2-5 degree C 
difference).

It is hard to numerically quantify the difference in the IRT readings caused by the change 
in the mirror. We can only warn the user that between January 1 and June 3 the MWRP 
readings are 8 to 15 degree higher than the skyrad IRT.

• Raw data stream - documentation not supported(raw)

• Zenith-pointing infrared temperature at 10um(infraredTemperature)

• Raw data stream - documentation not supported(raw)

NIM/MWRP/M1 - Reprocessed: IRT configuration setting error

The infrared thermometer settings (IRT) were not configured as specified by the 
manufacturer. The analog output was set to a range of -60 to +50 C (0-10V) instead of -50 to +50 C 
(0-10V). The settings were changed on April 20. The IR temperatures should be slightly 
smaller than reported.

The data have been reprocessed to correct the IRT calibrations.  Reprocessed data were 
archived in August 2006.

• Zenith-pointing infrared temperature at 10um(infraredTemperature)

NIM/MWRP/M1 - Reprocessed - New retrieval coefficients

Occasionally, the retrieved relative humidity was exceeding 120%. Upon reviewing the data 
it was noticed that the high values were appearing in the highest layers (above 8 km) and 
especially during spring season. Since retrievals at the highest levels are mainly 
affected by the climatology used to constrain the retrievals, we reviewed the statistical 
coefficients that were used to retrieve temperature and humidity. It was discovered that, in 
the training dataset (radiosonde), there were a few outliers (invalid radiosonde 
soundings) that had escaped the screening process and were affecting the computations of the 
retrieval coefficients.

We recomputed the retrieval coefficients with the newly screened set of radiosonde data 
and reprocessed all the previous data at Niamey.  The reprocessed data were archived in 
August 2006.

The new coefficients improve temperature and humidity profiles in two ways. The relative 
humidity will not exceed 120% in the upper layers and the temperature profiles will be in 
better agreement with the sonde in the first 4 km.

• Expected root-mean-square error in liquid water path retrieval(liquidWaterPathRmsError)
• Expected root-mean-square error in liquid water content retrieval(liquidWaterContentRmsError)
• Expected root-mean-square error in liquid water path retrieval using only 23.835
  and 30.0 GHz(liquidWaterPath2RmsError)
• Retrieved cloud liquid water content(liquidWaterContent)
• Derived relative humidity(relativeHumidity)
• Derived virtual temperature(virtualTemperature)
• Interpolated water vapor mixing ratio(waterVaporMixingRatio)
• Expected root-mean-square error in precipitable water retrieval(totalPrecipitableWaterRmsError)
• Expected root-mean-square error in water vapor density retrieval(waterVaporDensityRmsError)
• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Surface air temperature for last 5 minutes of previous hour(temperature)
• Retrieved water vapor density(waterVaporDensity)
• Interpolated dewpoint temperature(dewpointTemperature)
• Retrieved liquid water path(liquidWaterPath)
• Cloud-base height, from Micropulse LIDAR or Belfort LIDAR ceilometer(cloudBaseHeight)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Expected root-mean-square error in temperature retrieval(temperatureRmsError)
• Expected root-mean-square error in precipitable water retrieval using only
  23.835 and 30.0 GHz(totalPrecipitableWater2RmsError)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)

NIM/MWRP/M1 - 51.25 GHz channel calibration drifted

After a power outage on May 5 the 51.25 GHz had a slight change in the calibration. The 
resulting LWP computed by using all 6 channels increased of about 0.025 mm (25 g/m2).

• Microwave brightness temperature(brightnessTemperature)

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

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

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.

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

NIM/MWRP/M1 - Sun in radiometer's field of view

Around noon local time every day there is a spike in the brightness temperature data. This 
is due to the sun being in the field of view of the radiometer. PWV and LWP are affected 
as a consequence

• Expected root-mean-square error in precipitable water retrieval(totalPrecipitableWaterRmsError)
• Expected root-mean-square error in liquid water path retrieval(liquidWaterPathRmsError)
• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Expected root-mean-square error in liquid water content retrieval(liquidWaterContentRmsError)
• Zenith-pointing infrared temperature at 10um(infraredTemperature)
• Retrieved liquid water path(liquidWaterPath)
• Expected root-mean-square error in liquid water path retrieval using only 23.835
  and 30.0 GHz(liquidWaterPath2RmsError)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Microwave brightness temperature(brightnessTemperature)
• Retrieved cloud liquid water content(liquidWaterContent)
• Expected root-mean-square error in precipitable water retrieval using only
  23.835 and 30.0 GHz(totalPrecipitableWater2RmsError)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)

NIM/MWRP/M1 - IRTs do not agree with AERI

Since deployment at PYE, and then at NIM, the AMF SKYRAD IRT measured about 10K higher sky 
temperatures than the AERI and the MWRP IRT measured about 20K higher than the AERI.  
Several actions were taken to diagnose the problem including confirming the correct 
configuration of the IRTs and data logger, cleaning the mirror and lens, and replacing the mirror.

After several days of rain beginning 6/2/2006, the three instruments came into agreement. 
It is unknown whether this was a problem with the AERI, MWRP-IRT or SKYRAD-IRT.

• Zenith-pointing infrared temperature at 10um(infraredTemperature)

NIM/MWRP/M1 - Reprocessed: K-band calibration drift corrected

During October and November there was a drift in the K-Band calibration of the MWRP. This 
resulted in brightness temperatures that were too high.

New calibration coefficients were derived from the median value of the noise diode 
temperature for the months of October and November and the data were reprocessed to apply the 
corrected calibrations.  The reprocessed data were archived in January 2007.

• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Retrieved liquid water path(liquidWaterPath)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Microwave brightness temperature(brightnessTemperature)
• Retrieved cloud liquid water content(liquidWaterContent)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)