International networks of automatic lidars and ceilometers (ALC) are gathering valuable data about the ABL. To automatically detect the height of the atmospheric boundary layer and its sublayers, advanced algorithms are required. Detailed quality control is needed to flag periods when layer detection is not reliable due to e.g. complex precipitation patterns.

To make the most of the different instrument-specific capabilities, two tailored algorithms (called STRATfinder and CABAM) have been developed in the framework of PROBE collaborations. Here we introduce recent advances and quality control procedures. Evaluation of the two methods at two E-PROFILE sites indicates both methods agree well on average. Results highlights that instrument uncertainties (such as low signal-to-noise ratio, incomplete optical overlap) clearly affect the uncertainty of layer heights detected.

The next step is to evaluate the capability of STRATfinder and CABAM to derive ABL layer heights across a diverse sensor network. This is addressed in the "ABL testbed" project, a PROBE collaboration in which the boundary layer height detection algorithms are applied to 11 E-PROFILE stations across Europe.