Moisture Sources And Downstream Hydroclimatic Contribution Of A Deforested Agricultural Frontier In Rondônia, South-Western Amazonia
Date:
Recommended citation: Sorí, R., Pérez-Alarcón, A., Stojanovic, M., Ernst, J., Nieto, R., Gimeno, L. (2026). Moisture Sources And Downstream Hydroclimatic Contribution Of A Deforested Agricultural Frontier In Rondônia, South-Western Amazonia. XL Reunión Bienal de la Real Sociedad Española de Física . Sevilla, 20-24 July 2026, pp286 https://bienalfisicasevilla2026.es/static/upload/ow222/events/ev784/Site/files/Libro_de_Abstracts_Bienal_2026-05.pdf
#Abstract
The region of Rondônia, in south-western Amazonia, has undergone intense land-use change since the 1980s, characterised by widespread deforestation and the expansion of agricultural areas, particularly soybean and maize croplands. These transformations may affect evapotranspiration, atmospheric moisture recycling and the hydroclimatic connectivity between Amazonian landscapes and downstream regions of South America. In this study, we analyse the evolution of dry conditions in Rondônia during 1980–2023 and examine its dual role as both a receptor and a source of atmospheric moisture. Using a Lagrangian moisture-tracking framework, we identify the main moisture sources that contribute to precipitation over Rondônia and quantify where moisture exported from this area is subsequently released as precipitation. Backwards and forward trajectories were computed using a 10-day residence time, allowing annual and seasonal moisture uptake and downstream moisture contribution to precipitation to be assessed. Dryness was evaluated using drought-related hydroclimatic indicators such as the standardised precipitation index (SPI) and the standardised precipitation-evapotranspiration index (SPEI). The results reveal that the most important moisture sources for this region are the southeastern Amazon, Cerrado, and tropical eastern South Atlantic Ocean. An intensification of dry conditions in Rondônia is consistent with the precipitation decline, less moisture supply from the terrestrial sources, and agricultural expansion. At the same time, the region remains strongly connected to broader South American moisture pathways, contributing water vapour to regions located further downstream. These contributions also help sustain precipitationdependent vegetation, highlighting the importance of Rondônia in regional atmospheric moisture redistribution and land–atmosphere interactions.