Huang Xingying, Swain Daniel L
Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO. USA.
Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA, USA.
Sci Adv. 2022 Aug 12;8(32):eabq0995. doi: 10.1126/sciadv.abq0995.
Despite the recent prevalence of severe drought, California faces a broadly underappreciated risk of severe floods. Here, we investigate the physical characteristics of "plausible worst case scenario" extreme storm sequences capable of giving rise to "megaflood" conditions using a combination of climate model data and high-resolution weather modeling. Using the data from the Community Earth System Model Large Ensemble, we find that climate change has already doubled the likelihood of an event capable of producing catastrophic flooding, but larger future increases are likely due to continued warming. We further find that runoff in the future extreme storm scenario is 200 to 400% greater than historical values in the Sierra Nevada because of increased precipitation rates and decreased snow fraction. These findings have direct implications for flood and emergency management, as well as broader implications for hazard mitigation and climate adaptation activities.
尽管近期严重干旱频发，但加利福尼亚面临着一种普遍未得到充分重视的严重洪水风险。在此，我们结合气候模型数据和高分辨率天气建模，研究了能够引发“特大洪水”状况的“合理最坏情况”极端风暴序列的物理特征。利用社区地球系统模型大集合的数据，我们发现气候变化已经使引发灾难性洪水事件的可能性增加了一倍，但由于持续变暖，未来可能还会有更大幅度的增加。我们还发现，由于降水率增加和积雪比例下降，未来极端风暴情景下的径流比内华达山脉的历史值高出200%至400%。这些发现对洪水和应急管理有直接影响，对减灾和气候适应活动也有更广泛的影响。
