ABSTRACT: We used climate models to assess the effects of 2 distinct anthropogenic forcings on the water budget in the Amazon basin: (1) increasing global greenhouse gases under the RCP8.5 scenario, and (2) land cover change caused by deforestation. The Eta regional climate model, driven by the Brazilian Earth System Model version 2.5 (BESM 2.5), was used to simulate the climate response under the RCP8.5 scenario and due to deforestation throughout the 21^st century. Changes in energy and water budgets led to an increase in temperature that reached 5°C throughout the basin. In the RCP8.5 scenario, moisture convergence, precipitation and evapotranspiration all decreased. In this scenario, the positive feedback mechanism was predominant, as the reductions in evapotranspiration and moisture convergence acted in the same direction to reduce precipitation. In the future deforestation scenarios, reductions in precipitation were even stronger. In this case, the negative feedback mechanism predominated, in which the relative reduction in evapotranspiration was greater than the reduction in precipitation, leading to an increase in moisture convergence over the region. Changes in temperature and the water cycle were intensified in the future deforestation scenarios. These results show that the 2 anthropogenic factors can change the water budget and cause an imbalance in the climate-biome system in the Amazon basin, highlighting the need for public conservation policies to halt the increase in environmental degradation in the Amazon basin and to reduce greenhouse gases emissions due the burning of fossil fuels.

中文翻译：

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RCP 8.5和毁林情景下亚马逊流域的水预算变化

摘要：我们使用气候模型来评估2种不同的人为强迫对亚马逊河流域水预算的影响：（1）在RCP8.5情景下全球温室气体增加，以及（2）毁​​林造成的土地覆盖变化。埃塔区域气候模式，由巴西地球系统模式2.5版（2.5 BESM）驱动，用于模拟RCP8.5情景下，并且由于整个21砍伐森林对气候的响应^ST世纪。能源和水预算的变化导致整个流域的温度上升到5°C。在RCP8.5情景中，水分汇聚，降水和蒸散量均减少。在这种情况下，正反馈机制占主导地位，因为蒸散量和水分汇聚的减少作用方向相同，以减少降水。在未来的森林砍伐情景中，降水量的减少甚至更大。在这种情况下，负反馈机制占主导地位，在该机制中，蒸散量的相对减少量大于降水量的减少量，从而导致该地区的水分收敛增加。在未来的森林砍伐情景中，温度和水循环的变化加剧了。