Federal University of Viçosa, Department of Agricultural Engineering, Viçosa, MG 36570-900, Brazil.
Federal University of Espírito Santo, Department of Forest and Wood Sciences, Jerônimo Monteiro, ES 29550-000, Brazil.
Sci Total Environ. 2023 Sep 15;891:164557. doi: 10.1016/j.scitotenv.2023.164557. Epub 2023 Jun 6.
In this study, we used a large national database to assess the rainfall erosivity (RE) patterns in time and space over the Brazilian territory. Thereby, RE and erosivity density (ED) values were obtained for 5166 rainfall gauges. Also, the concentration of the RE throughout the year and the RE's gravity center locations were analyzed. Finally, homogeneous regions regarding RE values were delimited and estimative regression models were established. The results show that Brazil's mean annual RE value is 5620 MJ mm ha h year, with considerable spatial variation over the country. The highest RE magnitudes were found for the north region, while the northeast region shows the lowest values. Regarding the RE's distribution throughout the year, in the southern region of Brazil, it is more equitable, while in some spots of the northeastern region, it is irregularly concentrated in specific months. Further analyses revealed that for most of the months, the RE's gravity centers for Brazil are in the Goiás State and that they present a north-south migration pattern throughout the year. Complementarily, the ED magnitudes allowed the identification of high-intensity rainfall spots. Additionally, the Brazilian territory was divided into eleven homogeneous regions regarding the RE patterns and for each defined region, a regression model was established and validated. These models' statistical metrics were considered satisfactory and, thus, can be used to estimate RE values for the whole country using monthly rainfall depths. Finally, all database produced are available for download. Therefore, the values and maps shown in this study are relevant for improving the accuracy of soil loss estimates in Brazil and for the establishment of soil and water conservation planning on a national scale.
在这项研究中，我们使用了一个大型国家数据库来评估巴西境内时间和空间上的降雨侵蚀力 (RE) 模式。由此，我们获得了 5166 个雨量计的 RE 和侵蚀密度 (ED) 值。此外，还分析了全年的 RE 浓度和 RE 的重力中心位置。最后，划定了 RE 值均匀的同质区域，并建立了估计回归模型。结果表明，巴西的年平均 RE 值为 5620 MJ mm ha h year，在全国范围内存在相当大的空间变化。北方地区的 RE 值最高，而东北地区的值最低。关于全年的 RE 分布，巴西南部地区分布更均匀，而东北部的一些地区则在特定月份不均匀地集中。进一步的分析表明，在大多数月份，巴西的 RE 重力中心位于戈亚斯州，并且它们全年呈现南北迁移模式。此外，ED 值可以识别高强度降雨点。此外，巴西领土根据 RE 模式被划分为十一个同质区域，为每个定义的区域建立并验证了一个回归模型。这些模型的统计指标被认为是令人满意的，因此可以使用每月的降雨量来估算整个国家的 RE 值。最后，所有生成的数据库都可供下载。因此，本研究中显示的数值和地图对于提高巴西土壤流失估算的准确性以及在全国范围内进行水土保持规划具有重要意义。
