{'fraction_non_alphanumeric': 0.014857142857142857, 'fraction_numerical': 0.006857142857142857, 'mean_word_length': 5.125874125874126, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Improved near-range performance of a low-cost one lens lidar scanning the boundary layer

The enhanced single lens optical concept and fast electronics improve the lidar ceilometer Vaisala CL31 for a reliable workhorse to profile the boundary layer and determine mixing layer height. Lately there have been several developments of the system regarding hardware, measurement routine, and evaluation software. Backscatter profiles collected during measuring campaigns in two German towns are presented to show the effect of these further developments on overall system performance. The main focus of this paper is the ability of the CL31 ceilometer to determine very low mixing layer heights, e.g. during winter temperature inversion periods. Temperature and wind profiles from a RASS co-located to a CL31 in Augsburg and from a weather mast in Hamburg are used for comparison.