Temperature and humidity profile retrievals from ground-based microwave radiometers during TUC

Thermodynamic atmospheric profiles have been retrieved from ground-based microwave radiometers during the Temperature, hUmidity, and Cloud (TUC) profiling campaign. A variety of inversion methods is presented, in terms of requirements, advantages, and limitations. Results confirm the theoretical expectation that retrievals’ accuracy and resolution degrade steadily with height up to 3 km, then more rapidly. At higher levels the retrievals’ accuracy does not improve on that of a Numerical Weather Prediction model, which provides a background for the variational technique. Most retrieval methods produce a bias in the temperature profile above 1 km, which may be due to a bias in the absorption model used and/or observations at 51–54 GHz. Elevation scanning is shown to improve the accuracy and resolution of the retrievals in the boundary layer, but is limited by technical shortcomings.