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.

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

• Pressure, lifting condensation level(liftingCondensationLevelPres)
• time_offset
• liquidWaterPath2RmsError
• frequency
• Pressure, barometric. at instrument height (1 or 2 m)(surfacePressure)
• elevation
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)
• wetWindowFlag
• liquidWaterContentRmsError
• Barometric pressure(pressure)
• Pressure, level of free convection(levelFreeConvectionPres)
• Retrieved dewpoint temperature(dewpointTemperature)
• totalPrecipitableWaterRmsError
• Pressure, equilibrium level(equilibriumLevelPres)
• infraredTemperature
• Height, lifting condensation level(liftingCondensationLevel)
• Energy, potential, convective, available, from RUC model(cape)
• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• Temperature, virtual, vert. prof. sfc-10km, fr. wtr. vap. dens. and temp. prof.(virtualTemperature)
• Height, cloud base, height where IR temp. matches retrieved temp. profile(cloudBaseHeight)
• Density, water vapor, at instrument height (1 or 2 m)(surfaceWaterVaporDensity)
• dataQualityFlags
• Retrieved water vapor mixing ratio(waterVaporMixingRatio)
• Height, level of free convection(levelFreeConvection)
• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• base_time
• Pressure, associated geometric height, at altitude, NGM model output(height)
• liquidWaterPathRmsError
• waterVaporDensityRmsError
• Temperature, air, at instrument height (1 or 2 m)(surfaceTemperature)
• totalPrecipitableWater2RmsError
• temperatureRmsError
• Humidity, relative, at instrument height (1 or 2 m)(surfaceRelativeHumidity)
• alt
• Density, water vapor, prof. from sfc.-10 km, der. from Tbright stat. retrvl.(waterVaporDensity)
• Microwave brightness temperature(brightnessTemperature)
• azimuth
• Humidity, relative, prof. from sfc.-10km, from water vap. dens. and temp. prof.(relativeHumidity)
• time
• lon
• Liquid water content, cloud, vert. prof. sfc.-10km, from Tbright stat. retrvl.(liquidWaterContent)
• Height, equilibrium level(equilibriumLevel)
• lat
• blackbodyTemperature
• Water vapor, tot. precipitable, from Tbright, 23.835 & 30.0 GHz, stat. retrvl.(totalPrecipitableWater2)
• Air temperature(temperature)

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

NIM/SONDE/M1 - RH data incorrect.

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

• Dewpoint Temperature(dp)
• Humidity, relative(rh)

NIM/MET/M1 - Software problem

Intermittent Failure of Logger to read data from the Barometer.

• Barometric Pressure(atmos_pressure)

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.

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• Density, water vapor, prof. from sfc.-10 km, der. from Tbright stat. retrvl.(waterVaporDensity)
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)
• Microwave brightness temperature(brightnessTemperature)
• Retrieved dewpoint temperature(dewpointTemperature)
• Humidity, relative, prof. from sfc.-10km, from water vap. dens. and temp. prof.(relativeHumidity)
• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• Liquid water content, cloud, vert. prof. sfc.-10km, from Tbright stat. retrvl.(liquidWaterContent)
• Temperature, virtual, vert. prof. sfc-10km, fr. wtr. vap. dens. and temp. prof.(virtualTemperature)
• Water vapor, tot. precipitable, from Tbright, 23.835 & 30.0 GHz, stat. retrvl.(totalPrecipitableWater2)
• Air temperature(temperature)
• Retrieved water vapor mixing ratio(waterVaporMixingRatio)

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

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.

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

• infraredTemperature

• AVHRR satellite images for Darwin from BOM (RAW)(raw)

NIM/MET/M1  - ORG failure

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

• ORG precipitation rate mean(org_precip_rate_mean)

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.

• 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.

• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• liquidWaterPathRmsError
• liquidWaterPath2RmsError
• waterVaporDensityRmsError
• totalPrecipitableWater2RmsError
• temperatureRmsError
• Density, water vapor, prof. from sfc.-10 km, der. from Tbright stat. retrvl.(waterVaporDensity)
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)
• liquidWaterContentRmsError
• Retrieved dewpoint temperature(dewpointTemperature)
• totalPrecipitableWaterRmsError
• Humidity, relative, prof. from sfc.-10km, from water vap. dens. and temp. prof.(relativeHumidity)
• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• Temperature, virtual, vert. prof. sfc-10km, fr. wtr. vap. dens. and temp. prof.(virtualTemperature)
• Liquid water content, cloud, vert. prof. sfc.-10km, from Tbright stat. retrvl.(liquidWaterContent)
• Height, cloud base, height where IR temp. matches retrieved temp. profile(cloudBaseHeight)
• Water vapor, tot. precipitable, from Tbright, 23.835 & 30.0 GHz, stat. retrvl.(totalPrecipitableWater2)
• Air temperature(temperature)
• Retrieved water vapor mixing ratio(waterVaporMixingRatio)

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/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

• Microwave brightness temperature(brightnessTemperature)
• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• totalPrecipitableWaterRmsError
• liquidWaterPathRmsError
• infraredTemperature
• liquidWaterPath2RmsError
• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• totalPrecipitableWater2RmsError
• Liquid water content, cloud, vert. prof. sfc.-10km, from Tbright stat. retrvl.(liquidWaterContent)
• Water vapor, tot. precipitable, from Tbright, 23.835 & 30.0 GHz, stat. retrvl.(totalPrecipitableWater2)
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)
• liquidWaterContentRmsError

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. 
The cause of the discrepancy was probably dust accumulation on the lens of the instrument

• 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.

• Microwave brightness temperature(brightnessTemperature)
• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• Liquid water content, cloud, vert. prof. sfc.-10km, from Tbright stat. retrvl.(liquidWaterContent)
• Water vapor, tot. precipitable, from Tbright, 23.835 & 30.0 GHz, stat. retrvl.(totalPrecipitableWater2)
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)

NIM/MET/M1 - ORG underestimated precipitation

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

• ORG precipitation rate mean(org_precip_rate_mean)

NIM/MET/M1/S1 - 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.

• Rain, surface, 1-min avg(precip_rate_mean)
• precip_rate_sd
• precip_rate_max
• precip_rate_min

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 vector mean(wspd_vec_mean)
• Wind speed, lower, 1-min avg(wspd_arith_mean)

NIM/MET/S1 - 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_spd_arith_min
• Vector-averaged Wind Speed(wind_spd_vec_avg)
• Wind speed, lower, 1-min avg(wind_spd_arith_avg)
• wind_spd_arith_max
• wind_spd_arith_sd

NIM/MET/M1 - PWD cumulative precipitation incorrect

The Present Weather Detector is a serial sensor.  The MET system datalogger reads in the 
data from this sensor.  During the time in question serial comms problems were causing the 
data from the sensor to be read incorrectly.  The data for one variable showed up in 
data for another variable or not at all.  We reprocessed the data to correct as much of this 
error as we could.  The cumulative rainfall variable was calculated from the 
instantaneous rainfall variable during reprocessing.  Since we cannot be entirely sure all 
cumulative rainfall values are correct or were completely captured the cumulative rainfall data is 
considered to be unreliable.  This issue shows up when comparing the cumulative rainfall 
data at the end of the day 07/31/2006 (79.08) and the beginning of the next day 
08/01/2006 (3.17).  Clearly we were either under or over-estimating the cumulative rainfall.

• pwd_cumul_rain

NIM/MET/M1 - PWD 1 minute rainfall data suspect

The Present Weather Detector is a serial sensor.  The MET system datalogger reads in the 
data from this sensor.  During the time in question serial comms problems were causing the 
data from the sensor to be read incorrectly.  The data for one variable showed up in 
data for another variable or not at all.  We reprocessed the data to correct as much of this 
error as we could. We cannot be entirely certain that all rainfall values are correct or 
were captured properly.  It is possible that some values were missed completely.

• pwd_precip_rate_mean_1min