Center for Bottomland Hardwoods Research, USDA Forest Service, Mississippi State, MS, 39762, USA.
Department of Ecology, South China Agricultural University, Guangzhou, 510642, China.
Sci Rep. 2020 Jul 30;10(1):12802. doi: 10.1038/s41598-020-69508-8.
Variations in long-term precipitation trends due to climate forcings have been observed in many parts of the world, exacerbating hydrological uncertainties to predicting droughts, floods, water resource availability, and ecosystem services. The Lower Mississippi River Alluvial Valley (LMRAV) is an important economic region of the midsouth USA, which is prone to natural disasters from extreme climate events and is known historically for cyclic flooding events and, within the last 20 years, for groundwater level declines. However, our knowledge of long-term precipitation trends in this region is fragmented. Using 100-year historic daily precipitation data from six stations of forest lands along with multivariate statistical analysis, we found that there were significant increasing trends (p ≤ 0.05) in annual precipitation near the south coastal area of the LMRAV and only marginally increasing trends in the northern area. Spatial variation in seasonality was observed at the decadal scale with increasing trends in fall near the coastal area and in spring around the north area. In addition to becoming wetter, the coastal area also experienced higher precipitation intensity with shorter return period over the past 100 years. These findings are useful to water resource managers for adapting to changing climate conditions in the LMRAV.
由于气候强迫因素，世界上许多地区都观察到了长期降水趋势的变化，这加剧了预测干旱、洪水、水资源可利用性和生态系统服务方面的水文不确定性。密西西比河下游冲积平原（LMRAV）是美国中南部的一个重要经济区域，容易受到极端气候事件的自然灾害影响，历史上以周期性洪水事件而闻名，在过去 20 年里，还以地下水水位下降而闻名。然而，我们对该地区长期降水趋势的了解是零散的。本研究使用沿 LMRAV 南部沿海地区的六个森林地带的 100 年历史每日降水数据和多元统计分析，发现靠近 LMRAV 南部沿海地区的年降水量呈显著增加趋势（p≤0.05），而北部地区仅略有增加趋势。在十年尺度上观察到季节性的空间变化，沿海地区秋季呈增加趋势，北部地区春季呈增加趋势。在过去的 100 年里，除了变得更加湿润之外，沿海地区还经历了更高的降水强度和更短的重现期。这些发现对水资源管理者适应 LMRAV 不断变化的气候条件有用。
