by Nicolae Ajtai

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COST-TOPROF J-CAL (Joint microwave CALibration experiment) 25-29 august 2014, Lindenberg, Germany

From August 25th to 29th I participated in the Joint microwave CALibration experiment (J-CAL) at the DWD Lindenberg Meteorological Observatory. The aim of this campaign was to assess the performance of standardized calibration routines of different microwave radiometers under similar external conditions. The campaign instrumentation consited of two Radiometrics profiler (DWD Lindenberg) and 3 RPG HATPRO instruments of different series: G1 (Schneefernerhaus, 2005), G2 (IMGW Poland, 2008) G4 (RPG demonstrator, 2014). Extra radiosondes (in addition to the 4 daily sondes) were also available.

In order to increase the reliability of the retreived brightness temeprature and liquid water path products a better quantification of the errors associated to the callibration process must be made.

The major activities carried out during this campaign focused on quantifying the errors occurring within the two types of calibration processes of the microwave radiometers (absolute LN2 and automatic calibrations). A series of optimal calibration criteria were proposed based on standard procedures from the manufacturers. The final outcome of this campaign will be a series of methods to describe systematic and random uncertainties on the retrieved brightness temperature based on the above mentioned calibration criteria.


The participation to this campaign was very useful for my current research activity, which focuses on the detection of relatively small increases of brightness temperature values in specific channels of the microwave radiometer. Therefore an optimal characterization of the associated errors is critical.

*Financial support of TOPROF (COST Action ES1303) is gratefully acknowledged.

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