Future climate change is predicted to increase precipitation volume in Sweden, and also to modify precipitation patterns and produce more intense rainfall events. This study examined the impact of such changes in three small Swedish watersheds dominated by agricultural land. The Soil and Water Assessment Tool (SWAT) was used to investigate the relationship between changes in precipitation (monthly and daily) and monthly water partitioning between runoff, soil water content, and evapotranspiration. A climate ensemble produced from Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 and five different global climate models, regionalized by the Swedish regional climate model RCA4, was used to feed the SWAT model. The results showed similar outcomes for the three sites, with an increase in total monthly precipitation often associated with an increase in high daily rainfall events. Increased intensity of rainfall, particularly events > 15 mm/day, was associated with an increase in runoff, but not in soil water content. In the few cases where monthly precipitation decreased, soil water content also decreased. The main impact on all hydrological components of the system appeared to be more significant during the middle of the cropping season (May–August) than at the beginning (April) or end (September). These conclusions emerge despite the climate model ensemble underestimating the heaviest daily rainfall events. Overall, this study showed that the projected increasing trend in seasonal rainfall in southern Sweden would not result in more soil water being available for crop production.

预计未来的气候变化将增加瑞典的降水量，并改变降水模式并产生更强烈的降雨事件。这项研究考察了这种变化对三个以农业土地为主的瑞典小流域的影响。土壤和水评估工具（SWAT）用于调查降雨变化（每月和每天）与径流，土壤含水量和蒸散量之间每月水分配之间的关系。由代表性浓度路径（RCP）情景4.5和8.5以及由瑞典区域气候模式RCA4进行区域划分的五种不同的全球气候模式所产生的气候集合用于提供SWAT模型。结果显示这三个地点的结果相似，每月总降水量的增加通常与每日高降水量事件的增加有关。降雨强度增加，特别是> 15 mm /天的事件，与径流增加有关，但与土壤含水量无关。在少数情况下，月降水量减少，土壤含水量也减少。在种植季节的中期（5月至8月），对系统所有水文要素的主要影响似乎比开始（4月）或结束（9月）的影响更大。尽管气候模型集合低估了每天最大的降雨事件，但仍得出了这些结论。总体而言，这项研究表明，瑞典南部季节性降雨的预计增加趋势不会导致更多的土壤水可用于作物生产。