Impacts of the future Amazon deforestation on the precipitation over the Peruvian central Andes and related atmospheric features

Saavedra M.; Junquas C.; Takahashi K.; Silva Y.; Espinoza J.-C.; Sierra J.-P. · Atmospheric Research (2026) · DOI: 10.1016/j.atmosres.2026.109016

Resumen

This study investigates the impact of a 40% Amazon deforestation scenario (projected for 2050) on precipitation over the central Peruvian Andes during five austral summer seasons (DJF 2001–2006) using high-resolution (1 km) WRF simulations. While a widespread rainfall reduction pattern is observed over the Amazon-Andes transition zone, statistically significant decreases (p < 0.10) at the gridpoint level are primarily concentrated near rainfall hotspots in the Amazon-Andes transitions zone, reaching an average reduction of 12% (−1.4 mm day−1). This drying signal is physically associated with a weakening of the South American Low-Level Jet (LLJ) and reduced moisture influx, which specifically inhibits convective activity during the morning peak hours (23–11 LT). In the high-altitude Mantaro Basin, we observe a consistent drying pattern (−5%) that extends from the transition zone; although these changes are not statistically significant due to high interannual variability, the physical signal of precipitation reduction and dry air advection remains clear. Conversely, the western Andean ridges exhibit a localized precipitation increase (up to 20%) linked to intensified cross-barrier easterly wind anomalies reinforcing diurnal anabatic circulation. We further find that while 5 km resolution captures broad basin-scale patterns, convection-permitting scales (1 km) are essential for resolving these complex topographic effects. These findings highlight a critical vulnerability concentrated along the eastern slopes and the high Andes. The identified drying patterns, which are particularly pronounced in the Andes-Amazon transition zone (a global biodiversity hotspot) and extend into the highlands, pose a significant threat to endemic ecosystems and regional water security, specifically through reservoir inflow reduction and negative impacts on agriculture.

Instituciones: Pontificia Universidad Católica del Perú