FKB/MWRP/M1 - Reprocessed: Incorrect calibration

The software was started with the wrong calibration data.

Data reprocessed 2071227.

• 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)
• Air temperature(temperature)
• Retrieved water vapor mixing ratio(waterVaporMixingRatio)
• Height, lifting condensation level(liftingCondensationLevel)
• Water vapor, total precipitable, derived from Tbright using stat. retrvl.(totalPrecipitableWater)
• Humidity, relative, prof. from sfc.-10km, from water vap. dens. and temp. prof.(relativeHumidity)
• Temperature, virtual, vert. prof. sfc-10km, fr. wtr. vap. dens. and temp. prof.(virtualTemperature)
• Pressure, lifting condensation level(liftingCondensationLevelPres)
• Height, level of free convection(levelFreeConvection)
• Microwave brightness temperature(brightnessTemperature)
• liquidWaterPath2RmsError
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)
• Density, water vapor, prof. from sfc.-10 km, der. from Tbright stat. retrvl.(waterVaporDensity)
• Pressure, level of free convection(levelFreeConvectionPres)
• liquidWaterContentRmsError
• liquidWaterPathRmsError

FKB/SONDE/M1 - RH values may be slightly overcorrected.

The desiccant in the GC25 ground check set began to lose efficiency at the beginning of 
this time period.  Prior to 9/11/2007 the radiosonde RH readings while in the GC25 (assumed 
RH=0%) were below 1%RH.  The RH readings began to exceed 1%RH on 9/11/2007 and increased 
more or less exponentially to 2.3% RH by the end of 9/18/2007.  The desiccant was 
changed on 9/19/2007 and the radiosonde RH values while in the GC25 again dropped within the 
acceptable limit (< 0.5%RH, in fact).

Because the value obtained from the radiosonde while in the GC25 is subtracted from the 
subsequent RH values as part of the ground check procedure, it is likely that soundings 
done late in this period may be biased low by no more than 2%RH.  The exact amount of the 
correction applied is included in the netCDF header of each file.

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

FKB/MWRP/M1 - LN2 Calibration-

Between 1100 and 1500 there were two calibration attempts.

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

FKB/MWRP/M1 - Reprocessed: Updated 30-GHz calibration coefficient

On 9/17 the instrument was calibrated with liquid nitrogen. For the 30-GHz channel the 
results of calibration were not optimal and were causing a negative bias in the retrieved 
LWP.

On 10/9 the 30-GHz calibration parameters were updated with values derived from tip 
curves.

Data between 9/17 and 10/9 were reprocessed to correct the 30-GHz calibration.  
Reprocessed data were archived 20080122.

• Liquid water path, from brightness temperatures using statistical retrieval(liquidWaterPath)
• Microwave brightness temperature(brightnessTemperature)
• Liquid water path, from Tbright at 23.835 and 30.0 GHz only, using stat. retrvl.(liquidWaterPath2)

FKB/MWRP/M1 - Heavy rain and fog at the site

The months of November and December have been very rainy and wet at the AMF site. During 
rain events the radiometer does not work properly because of water accumulating on the 
window. In addition condensation and fog will affect the data causing very high brightness 
temperatures. Although the instrument is equipped with rain detection system to flag bad 
data, it is important that the user pays extra attention to the quality of the data during 
periods of continuous rain, drizzle or fog by applying the quality checks and screening 
for high brightness temperatures.

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

FKB/MWRP/M1 - Possible slight drift of V-band calibration

During the month of November and December the bias between model computations and 
measurements for the 51.25 and 52.28 GHz channels has slightly increased to about 3 K. This might 
be due to a slight drift in the calibration of these channels.

The calibration error associated with these data is increased, to 2-3 K, for these two 
months. See this plot for a comparison of measurements (solid lines) and model (red 
dots) for the 51.25 (black), 52.28 (blue) and 53.85-GHz (green) channels.

• Microwave brightness temperature(brightnessTemperature)

FKB/MWRP/M1 - Periodic decrease in the 30-GHz brightness temperature

Starting around 12/19 until the end of December, the 30-GHz brightness temperature started 
to show a periodic oscillation between 9 and 11 AM GMT. The cause of this is probably 
thermal instability of the radiometer since it does correspond with some larger 
oscillations of the mixer temperature. During this time external temperatures displayed large 
variations going from -10 C at night to about +5 C during the day. The corresponding liquid 
water path retrievals are affected showing periodic negative values.

Liquid water path retrievals between 12/19 and 12/31 are the most affected variable since 
they are largely affected by the 30-GHz channel. A time series plot of the data will 
clearly show the periodic fluctuation of the LWP variable.

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