FKB/MWRHF/M1 - Dew formation on window

During night time, when the humidity is very high (RH ~ 100%) data are strongly affected 
by dew formation on the window. 
This results in a smooth and large (80-150 K) increase of the brightness temperature from 
early night to sunrise. Data are affected mostly at night.

• Sky brightness temperature (90 GHz)(tbsky90)
• Sky brightness temperature (150 GHz)(tbsky150)

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.

• Retrieved liquid water path using only 23.835 and 30.0 GHz(liquidWaterPath2)
• Derived relative humidity(relativeHumidity)
• Retrieved total precipitable water vapor using only 23.835 and 30.0 GHz(totalPrecipitableWater2)
• Interpolated water vapor mixing ratio(waterVaporMixingRatio)
• Total precipitable water vapor, from microwave radiometer(totalPrecipitableWater)
• Retrieved water vapor density(waterVaporDensity)
• Interpolated dewpoint temperature(dewpointTemperature)
• Microwave brightness temperature(brightnessTemperature)
• Retrieved cloud liquid water content(liquidWaterContent)
• Derived virtual temperature(virtualTemperature)
• Retrieved liquid water path(liquidWaterPath)
• air temperature (NGM250 predicted)(temperature)

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/MWRHF/M1 - Questionable calibration

The instrument completed a tip curve calibration on June 30 and it did not calibrate again 
until Oct 13. Data during this time display large residuals (~ 6 K) when compared with 
model computations. It is likely that the tip curve calibration, although successful, 
wasn't good enough to have good accuracy.

Since this instrument is still under testing the users should use the data with caution. 
Although the accuracy of the model itself is still debated, large residuals between the 
measurements and the model between June and October are probably in large part due to the 
poor calibration.

• Sky brightness temperature (90 GHz)(tbsky90)
• Sky brightness temperature (150 GHz)(tbsky150)