Water vapour information from the TROWARA microwave radiometer
The TROWARA microwave radiometer has been making column water vapour and liquid water measurements from the roof of the Institute of Applied Physics in Bern since late 1994. It operates from a lab inside the IAP building and views the sky through a microwave transparent window. This setup protects the instrument from precipitation and allows it to measure water vapour during light rain events and to continue measuring soon after heavy rain events. Trowara's view direction is south-east at 40 degrees elevation.
Further details are available on TROWARA's web page
Quality control of TROWARA data
The database interface automatically screens data for short term instrument problems or for occurences where the data were affected by rain. Users of the data should be aware that a number of improvements have been made to the instrument in the last few years, including a new calibration scheme. Thomas Ingold studied the TROWARA data over the 1995 to 1998 period and showed that the TROWARA data had a bias of approximately 2 mm. This is described in an IAP internal report. In contrast, the bias between TROWARA and either sonde, GPS or PFR was less than 0.5 mm for the years 2001 and 2003.
The pre-2001 data have now been corrected using a homogenisation technique. The data which can be downloaded over the web are the homogenised data.
Integrated Water Vapour (IWV) and Integrated Liquid Water (ILW) measured for the previous day by the TROWARA radiometer
Contactlast update: Sep. 2009