Observational Evidence of Vertical Drying Over Deforested Amazonia From <scp>GPS</scp> ‐ <scp>RO</scp> Data

ABSTRACT The Amazon rainforest is a critical component of the global climate system, with its vast vegetation driving the regional water cycle through evapotranspiration. However, deforestation is severely disrupting this balance, and most studies have focused primarily on surface‐level impacts. This study examines how deforestation affects the vertical structure of humidity in Amazonia, using high‐vertical‐resolution specific humidity profiles from GPS radio occultation (GPS‐RO) observations between 2007 and 2023. Gid cells across the region were classified by the percentage of accumulated forest loss (low deforestation, LD &lt; 10%; high deforestation, HD &gt; 50%) using data from the PRODES/INPE system. Results show consistent and significant drying in highly deforested areas, especially in the lower troposphere (below ~3–4 km), with the strongest reductions in specific humidity (up to −7.8 g kg −1 ) found below 1.5 km. This drying intensifies during the dry season (May–September), when forest‐driven evapotranspiration plays its greatest role. Humidity differences persist into the mid‐troposphere, suggesting possible changes in convective development or broader‐scale compensatory subsidence. The robustness of the signal was validated through integrated humidity profiles at different vertical layers, confirming that the observed drying is not a methodological artefact but a direct physical consequence of vegetation loss. These findings highlight the deep coupling between land cover and moisture dynamics in the tropics, with major implications for regional climate modelling and conservation strategies in the Amazon.