Planetary boundary layer height estimated at the Alcântara Launch Center

Sea and land breeze circulation and the internal boundary layer are some aspects that make it difficult to determine the coastal Planetary Boundary Layer (PBL) height ( h ). This paper evaluates the h estimation for the Alcantara Launch Center (CLA) in Maranhao state using 14 months of remote measurements obtained by a ceilometer and by the ERA5 reanalysis. This response depends on the concentration of aerosols and atmospheric humidity present. Mean results indicated that dry months (September to November, with  = 637  488 m) tend to have less hourly and seasonal variability of h compared to wet months (March to May, with  = 770  912 m). A higher mean error in the wet season was obtained with ERA5 PBL h ( h = 708  53 m over the land; e h = 648  46 m over the ocean) than in the dry season ( h = 18  89 m; e h = 46  77 m). The greater amount of atmospheric humidity during the rainy season increases the estimation uncertainty. This condition was more frequent at night due to typical rainfall in the place.