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An advanced microwave radiometer for profiling atmospheric parameters is described in this paper. The method accomplishing profiling is described. The innovations of the radiometer system, including utilization of a stable frequency synthesizer and the calibration system are described. The performance of several mathematical retrieval methods and representative profiles are presented, as well as several comparisons with radiosondes.

During the Swiss POLLUMET field experiments, a tethersonde measuring system was used to determine the vertical profiles and temporal evolutions of meteorological parameters and air pollutants such as NO2, O3, and hydrocarbons (HC). NO2 and O3 concentrations were measured by continuously operating commercially available sensors. HC components are sampled by a self-made sampling apparatus and adsorbed on to charcoal at different altitudes. The measuring techniques and the calibration procedures are described. The accuracies and interferences of the individual devices are extensively examined and are presented here. It was shown that the maximum deviations of all measured quantities ranged below 11 % even for very low concentrations. For the POLLUMET field experiments 1990 and 1991, vertical profiles of the measured components and their temporal evolution at different heights above ground are presented exemplarily. The results give insight into the behavior (formation and destruction) of air pollutants in the lower planetary boundary layer, they contribute to other measurements of mesoscale studies like POLLUMET, and can be used for model verification.