Spatiotemporal evolution of Amazonian convective boundary layer height associated with land use and land cover changes

The planetary boundary layer (PBL) mediates exchanges of heat, moisture, momentum, and chemical constituents between the surface and the free atmosphere. In the Amazon biome, where land use and land cover (LULC) changes have intensified over recent decades, changes in surface energy partitioning may alter convective boundary layer dynamics. This study provides a spatiotemporal analysis of convective boundary layer height (CBLH) over the Brazilian Amazon using ERA5 data and evaluates its relationship with LULC changes on the CBLH structure, as well as changes in sensible heat flux (H) and latent heat flux (LE) patterns over four decades, as depicted by the Bowen ratio (β). Results show a pronounced increase in CBLH, with values exceeding 1800 m in parts of the southern Amazon and marked increases in the southern and northeastern regions, particularly during the last two decades. Seasonal trend analysis indicates a weak wet-season CBLH trend of 0.72 m yr −1 and a stronger dry-season trend of 5.01 m yr −1 . In contrast to the wet season, the dry-season increase is strongly associated with LULC changes and with a shift in energy partitioning toward greater sensible heat flux. These results indicate that land-surface changes are closely linked to Amazonian lower-atmosphere dynamics, with potential implications for regional climate, convection, and the hydrological cycle. We therefore interpret these patterns as spatial associations rather than definitive causal attribution, because no formal attribution model separating LULC forcing from climatic variability was applied.