Data Quality Reports for Session: 104561 User: gp8 Completed: 02/28/2007


TABLE OF CONTENTS

DQR IDSubjectData Streams Affected
D060419.3NIM/MWRP/M1 - Instrument noise problemnimmwrpM1.00, nimmwrpM1.b1, nimmwrprawM1.00
D060420.5NIM/MWRP/M1 - IRT Sensor CalibrationnimmwrpM1.00, nimmwrpM1.b1, nimmwrprawM1.00
D060602.2NIM/MWRP/M1 - Reprocessed: IRT configuration setting errornimmwrpM1.b1
D060619.1NIM/MWRP/M1 - Reprocessed - New retrieval coefficientsnimmwrpM1.b1
D061003.3NIM/MWRP/M1 - IRTs do not agree with AERI nimmwrpM1.b1


DQRID : D060419.3
Start DateStart TimeEnd DateEnd Time
Subject:
NIM/MWRP/M1 - Instrument noise problem
DataStreams:nimmwrpM1.00, nimmwrpM1.b1, nimmwrprawM1.00
Description:
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.
Measurements:nimmwrprawM1.00:
  • Raw data stream - documentation not supported(raw)

nimmwrpM1.b1:
  • 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)
  • Temperature used to determine the backscatter profile(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)
  • Retrieved total precipitable water vapor(totalPrecipitableWater)

nimmwrpM1.00:
  • Raw data stream - documentation not supported(raw)


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DQRID : D060420.5
Start DateStart TimeEnd DateEnd Time
01/15/2006000006/03/20060000
Subject:
NIM/MWRP/M1 - IRT Sensor Calibration
DataStreams:nimmwrpM1.00, nimmwrpM1.b1, nimmwrprawM1.00
Description:
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.
Measurements:nimmwrprawM1.00:
  • Raw data stream - documentation not supported(raw)

nimmwrpM1.b1:
  • Zenith-pointing infrared temperature at 10um(infraredTemperature)

nimmwrpM1.00:
  • Raw data stream - documentation not supported(raw)


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DQRID : D060602.2
Start DateStart TimeEnd DateEnd Time
01/15/2006000004/21/20060000
Subject:
NIM/MWRP/M1 - Reprocessed: IRT configuration setting error
DataStreams:nimmwrpM1.b1
Description:
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.
Measurements:nimmwrpM1.b1:
  • Zenith-pointing infrared temperature at 10um(infraredTemperature)


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DQRID : D060619.1
Start DateStart TimeEnd DateEnd Time
Subject:
NIM/MWRP/M1 - Reprocessed - New retrieval coefficients
DataStreams:nimmwrpM1.b1
Description:
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.
Measurements:nimmwrpM1.b1:
  • 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)
  • Temperature used to determine the backscatter profile(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)
  • Retrieved total precipitable water vapor(totalPrecipitableWater)


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DQRID : D061003.3
Start DateStart TimeEnd DateEnd Time
01/09/2006000106/07/20061900
Subject:
NIM/MWRP/M1 - IRTs do not agree with AERI
DataStreams:nimmwrpM1.b1
Description:
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.
Measurements:nimmwrpM1.b1:
  • Zenith-pointing infrared temperature at 10um(infraredTemperature)


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