Climate Leads to Reversed Latitudinal Changes in Chinese Flood Peak Timing. Issue 6 (6th June 2022)

• Record Type: Journal Article
• Authors: Yang, Yixin; Yang, Long; Chen, Xiaodong; Wang, Qiang; Tian, Fuqiang
• Is Part Of: Earth's future. Volume 10:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-06
• Subjects: Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2022EF002726
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: Changes in river floods under a changing climate are of worldwide concerns, but relevant knowledge is limited especially over the East Asia monsoon region. Here we examine changes in flood peak timing based on the most comprehensive flood data set to date across China during 1961–2017. The temporal shifts of Chinese flood peak timing range from −19.0 days earlier to +14.0 days later per decade. Earlier flood occurrences are mainly observed in northern China, with delayed flood occurrences in the south. The spatial pattern of reversed latitudinal changes in flood timing leads to growing spatial extents of concurrent river floods over China. Soil moisture plays an important role in modulating such changes, despite precipitation determines the climatological mean dates of flood occurrences. Our results highlight a strong climate signal on the changes in flood timing over China, and call for coordinated efforts in alleviating expanding flood hazards related to the changes in flood timing. Plain Language Summary: Changes of river floods under a changing climate are of worldwide concerns, but relevant knowledge is still limited especially over East Asian monsoon region. Changes in dates of flood peak occurrences are preferably investigated to understand how climate change affects river floods. This is because flood peak timing, compared to flood peak magnitude, is less affected by water (e.g., dams) and land (e.g., urbanization) management practices. Based on the most comprehensive Chinese flood data set, we identify a strong climate signal on the changes in flood peak timing over China for the first time. Chinese floods tend to occur later in the south but earlier in the north over the past several decades. Considering floods in southern China are typically earlier than those in northern China, the reversed latitudinal changes in flood peak timing lead to enhanced temporal concentration of flood occurrences (i.e., seasonality) over China, and is further responsible for flooding with larger spatial extents across China. While monsoon rainfall largely determines the flood seasonality, we highlight the role of antecedent soil wetness in modulating changes in flood peak timing. Our results call for trans‐basin efforts in alleviating widespread flood hazards over the East Asian Monsoon region. Key Points: Southern (Northern) China witness delayed (earlier) annual flood peaks in the past six decades Reversed latitudinal changes in flood peak timing lead to the growing spatial extents of synchronous flooding over China Weak temporal correlation between flood and rainfall synchrony scale highlights the role of soil moisture in modulating flood peak timing