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Global changes in floods and possible mechanisms
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  • Shuyun Feng,
  • Jianyu Liu,
  • Yongqiang Zhang,
  • Hylke E Beck,
  • Xihui Gu
Shuyun Feng
CUG
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Jianyu Liu
Sun Yat-sen University

Corresponding Author:[email protected]

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Yongqiang Zhang
Institute of Geographic Sciences and Natural Resources Research
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Hylke E Beck
Princeton Universtiy
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Xihui Gu
China University of Geosciences (Wuhan)
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Abstract

While warming temperatures are known to increase atmospheric moisture capacity and heavy precipitation frequency; as yet there is little evidence for corresponding increases in floods. This study comprehensively examines global changes in multidimensional flood behaviors (magnitude, frequency, and duration), and aims to identify the possible mechanisms behind the heavy precipitation and flood change dichotomy. Our global assessment shows that floods become more frequent but not larger. Regionally, consistent changes can be observed among multidimensional flood behaviors, i.e., floods becoming larger in magnitude, more frequent, and longer in duration in some regions (e.g., North Europe), while smaller, less frequent, and shorter in other regions (e.g., South Australia). Attribution analysis indicates that spatial patterns of global flood trends are primarily controlled by shifts in atmospheric circulation patterns, terrestrial water storage changes, and temperature increases. The dams are crucial for reducing the floods, with the greatest impacts on flood magnitude, followed by flood frequency and duration. Catchment characteristics (i.e., vegetation coverage, irrigation, and urbanization) regulate the response of flood changes to changing environments.