城市景观对不同历时强降雨的影响及其未来变化

    Impact of urban landscape on extreme rainfall with varying durations and its future change trends

    • 摘要: 随着城市化进程的快速推进,城市景观格局发生显著变化,进一步加剧了城市气候的复杂性。尽管已有研究关注城市化对极端降雨的影响,但在深入理解不同类型的城市景观及其未来演变如何影响不同历时的极端降雨方面仍然存在不足。为此,基于6个城市景观指标,构建了时变非平稳广义位置尺度和形状加法模型(GAMLSS),并结合未来土地利用模拟模型(PLUS),探讨未来城市景观配置对极端降雨的影响。结果表明:①相较于传统平稳性模型,基于城市景观指标的非平稳广义加性模型在模拟城市极端降雨方面表现更优。②对于短历时极端降雨(≤3 h),不透水面积比例(ISP)、斑块密度(PD)和香农多样性指数(SHDI)出现在最佳非平稳模型中的频次较高;长历时极端降雨(>3 h)中,PD和SHDI的相对频率有所增加,而ISP的频率有所下降。③未来不同土地利用发展情景的降雨预测值虽略有差异,但空间分布趋势一致,短历时强降雨高值主要集中在中北部地区,而长历时强降雨高值影响范围更广,除中北部外,还包括东南沿海地区。研究成果可为城市化背景下的极端降雨预测及洪水风险评估提供参考。

       

      Abstract: With the rapid advancement of urbanization, urban landscape patterns have undergone significant changes, further intensifying the complexity of urban climate.Although previous studies have examined the impact of urbanization on extreme rainfall, there remains a significant research gap in understanding how different types of urban landscapes and their future evolution influence extreme rainfall events with varying durations.In this study, we construct a time-varying non-stationary generalized additive model for location, scale, and shape (GAMLSS) based on six urban landscape indicators, combine it with the Patch-generating Land Use Simulation (PLUS) model to explore the impact of future urban landscape configurations on extreme rainfall.The results indicate that: ① The non-stationary GAMLSS model based on urban landscape indicators outperforms traditional stationary models in simulating extreme urban rainfall.② For short-duration extreme precipitation events (≤3 h), the impervious surface percentage (ISP), patch diversity (PD), and Shannon′s diversity index (SHDI) appear more frequently in the optimal non-stationary models.In contrast, for long-duration extreme rainfall events (> 3 h), PD and SHDI exhibit an increase in relative frequency, while ISP shows a decrease.③ Under future scenarios of different land use development, although the design rainfall values of different land use scenarios show slight differences, the spatial distribution trends remain consistent.For short-duration heavy rainfall, areas with high design value are mainly concentrated in the central-northern region.In contrast, areas with high design value for long-duration heavy rainfall have a wider impact range, covering not only the central-northern region but also the southeastern coastal areas.This study can provide critical insights into extreme rainfall forecasting and flood risk assessment under the background of urbanization, contributing to the optimization of urban planning and disaster mitigation strategies.

       

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