The vertical resolution of ground-based microwave radiometers analyzed through a multiresolution wavelet technique

The spatial resolution of a ground-based microwave radiometer is analyzed through a multiresolution wavelet transform. This technique allows us to compare the ability of the instrument to detect perturbations in a profile under different observing configurations and different noise levels. The use of a wavelet transform applied to performance indicators enables us to isolate the altitude and scale of the perturbation providing an unambiguous definition of resolution. A suitable ensemble of channels and view angles can then be selected to optimize the performance at different altitudes and different resolutions. Several angle/channel configurations are simulated. Among the configurations examined, a scanning system with only one channel offered a resolution comparable to a multichannel system for boundary layer sensing. The simulation suggests that increasing the bandwidth in the multichannel system improves the performance of the fixed view configuration. For investigation above 1 km, a multichannel system with fixed angle seems to offer a better performance at a coarser resolution.