Validation of an Advanced Ceilometer-Based Boundary Layer Height Detection Algorithm

For nearly a decade, scientists have been using backscatter information from LIDAR ceilometers for observing boundary layer structures such as the daytime mixing layer. For users interested in the physical height of these structures, detection algorithms have been developed that retrieve this information throughout the day. While useful in many geographic locations, ceilometer based retrievals have been known to have difficulties in situations where multiple layers are detected within the lowest few kilometers of the backscatter profile and also in pristine atmospheres where the instruments receive little backscatter information. To address these difficulties, a new boundary layer detection algorithm has been developed. The algorithm provides a single value for boundary layer height at all times during the day, with a special focus on detection of the daytime mixed layer. To validate the performance of the algorithm, a series of radiosondes were launched at geographically diverse locations to serve as reference observations for co-located LIDAR ceilometers as part of a summertime field study. Statistics of the algorithm's detection ability are provided, along with challenges and future considerations.