The first ALINE measurements and intercomparison exercise on lidar inversion algorithms

Abstract

The first coordinated effort to perform simultaneous lidar measurements in Latin America was carried out as a pilot campaign between 10 and 14 September 2012. Four lidar stations contributed to the campaign measurements: Manaus, São Paulo, Concepción and Buenos Aires. Data from all four contributing stations were manually screened and a 1-h average cloud-free profile was selected from each one. These four elastic profiles were analyzed by four of the groups using their own elastic lidar algorithm. Here, the results for the particle backscatter coefficient are compared and discussed. We show that after five stages, the results have an agreement better than the typical uncertainty in the retrieval. Systematic errors found in different algorithms during the five stages of the exercise emphasize the need for analysis, measurements and data quality protocols. Difficulties involved in the coordination of the campaign and in the collaborative analysis are also highlighted.