Li Hao, Insua-Costa Damián, Koppa Akash, Geirinhas João Lucas, Keune Jessica, Holgate Chiara M, Dominguez Francina, Deman Victoria M H, Teuling Adriaan J, Miralles Diego G
Hydro-Climate Extremes Lab, Ghent University, Ghent, Belgium.
Department of Environmental Science & Technology, University of Maryland, College Park, MD USA.
NPJ Clim Atmos Sci. 2025;8(1):279. doi: 10.1038/s41612-025-01152-3. Epub 2025 Jul 23.
Stable and predictable wet-season rainfall is crucial for soybean production in Brazil. However, climate and land-use changes, particularly Amazon deforestation, have increased rainfall variability in the region in recent decades. Here, we investigate long-term growing-season rainfall changes over two major soybean breadbaskets in Brazil from the perspective of atmospheric moisture transport. Utilising a novel moisture tracking framework based on a Lagrangian model guided by observations, we identify moisture source regions where evaporation contributed to rainfall over these breadbaskets. Furthermore, we quantify the relative contributions of source evaporation versus atmospheric (thermo)dynamics changes to downwind rainfall variability. Our results indicate that deforestation-induced evaporation declines have negatively impacted downwind rainfall in the breadbasket regions. However, strengthened circulation, evidenced by increased water vapour transport and low-level wind speeds consistent with decreased tree cover, has enhanced moisture transport from upwind regions (including Amazonia and the Atlantic Ocean) to the Brazilian soybean breadbaskets. This highlights the compensatory effects of deforestation on rainfall through decreased evaporation and altered atmospheric (thermo)dynamics, and how these effects may influence downwind soybean productivity in South America. Further understanding these interactions is critical for developing land management strategies to mitigate the agricultural impacts of climate change in the region.
稳定且可预测的雨季降雨对巴西的大豆生产至关重要。然而，近几十年来，气候和土地利用变化，尤其是亚马逊地区的森林砍伐，增加了该地区降雨的变异性。在此，我们从大气水分输送的角度研究巴西两个主要大豆产区生长季的长期降雨变化。利用基于观测引导的拉格朗日模型的新型水分追踪框架，我们确定了蒸发对这些产区降雨有贡献的水分源区。此外，我们量化了源蒸发与大气（热）动力学变化对下游降雨变异性的相对贡献。我们的结果表明，森林砍伐导致的蒸发量下降对产区下游的降雨产生了负面影响。然而，水汽输送增加和低空风速与树木覆盖减少一致所证明的环流增强，增强了从上游地区（包括亚马逊地区和大西洋）向巴西大豆产区的水分输送。这凸显了森林砍伐通过减少蒸发和改变大气（热）动力学对降雨的补偿作用，以及这些作用如何可能影响南美洲下游地区的大豆生产力。进一步了解这些相互作用对于制定土地管理策略以减轻该地区气候变化对农业的影响至关重要。
