100-Year Lower Mississippi Floods in a Global Climate Model: Characteristics and Future Changes
100-Year Lower Mississippi Floods in a Global Climate Model: Characteristics and Future Changes
复制标题
全球气候模型中密西西比州洪水减少 100 年：特征和未来变化
作者：
K. Wiel;S. Kapnick;G. Vecchi;J. Smith;P. Milly;L. Jia
密西西比流域的洪水会对社会、自然和经济产生巨大的负面影响。了解现在和未来洪水的驱动因素，对于风险管理和基础设施规划目的是相关的。我们调查的驱动程序100年返回较低的密西西比河洪水使用一个全球耦合气候模式与集成的地表水模块。该模型提供了3400年的物理一致的数据，从静态气候，与现有的观测数据（相对较短的记录，不完整的陆面数据，瞬态气候）。在模型的百年一遇洪水之前的几个月里，如极端月流量所示，高于平均水平的降雨和降雪导致潮湿的地下条件和积雪的积累，使河流系统容易发生这些重大洪水事件。来自北方密苏里州和密西西比上游集水区积雪的融水使河流系统处于最佳状态，使其对随后俄亥俄州和田纳西州集水区高于平均水平的降水敏感。瞬态强迫实验的集合被用来调查过去和预测的人为气候变化对极端洪水的影响。尽管极端降水显著增加，极端融雪显著减少，极端洪水显著减少，但在模型集合中，100年一遇洪水的发生没有统计学显著的预测趋势。结果强调了考虑极端洪水的完全耦合的陆-气系统的重要性。这一初步分析为进一步调查提供了途径，包括与不太极端的洪水特征进行比较，对模型配置的敏感性，人类用水管理的作用以及对未来洪水风险管理的影响。
Floods in the Mississippi basin can have large negative societal, natural, and economic impacts. Understanding the drivers of floods, now and in the future, is relevant for risk management and infrastructure-planning purposes. We investigate the drivers of 100-yr-return lower Mississippi River floods using a global coupled climate model with an integrated surface water module. The model provides 3400 years of physically consistent data from a static climate, in contrast to available observational data (relatively short records, incomplete land surface data, transient climate). In the months preceding the model’s 100-yr floods, as indicated by extreme monthly discharge, above-average rain and snowfall lead to moist subsurface conditions and the buildup of snowpack, making the river system prone to these major flooding events. The meltwater from snowpack in the northern Missouri and upper Mississippi catchments primes the river system, sensitizing it to subsequent above-average precipitation in the Ohio and Tennessee catchments. An ensemble of transient forcing experiments is used to investigate the impacts of past and projected anthropogenic climate change on extreme floods. There is no statistically significant projected trend in the occurrence of 100-yr floods in the model ensemble, despite significant increases in extreme precipitation, significant decreases in extreme snowmelt, and significant decreases in less extreme floods. The results emphasize the importance of considering the fully coupled land–atmosphere system for extreme floods. This initial analysis provides avenues for further investigation, including comparison to characteristics of less extreme floods, the sensitivity to model configuration, the role of human water management, and implications for future flood-risk management.
影响因子：
64.8
作者：
Munoz, Samuel E.;Giosan, Liviu;Donnelly, Jeffrey P.
通讯作者：
Donnelly, Jeffrey P.