降水频率和强度温度敏感性的水文约束

中文摘要 AI 辅助

为加深对降水频率和强度随增温变化的理解，我们将耦合的陆-气水平衡与一个明确依赖降水频率和事件深度的随机水文模型相结合。我们发现降雨频率和强度协变之间存在线性关系，其中斜率是由干燥指数和蓄水指数决定的水文敏感性，截距是与水汽辐合、潜在蒸散发和有效蓄水容量变化相关的强迫项。虽然降雨频率或强度的任一给定相对变化都会产生平均速率的相同相对变化，但降雨强度还通过改变相对于降雨深度的陆地蓄水量来影响径流系数。这意味着频率和强度对水循环有不同的影响，使得频率-强度斜率可以偏离-1。对长期MOPEX记录的分析表明，强迫项主要由水汽辐合主导，且频率-强度关系从湿润到干燥区域变得更陡，与理论预测的斜率一致。该框架为观测到的降水频率和强度之间的负协变提供了物理解释，并阐明了水文分配和大气水汽供应在其对增温响应中的作用。

英文摘要

To improve understanding of how precipitation frequency and intensity change with warming, we combine the coupled land--atmosphere water balance with a stochastic hydrological model that retains explicit dependence on precipitation frequency and event depth. We find a linear relationship between co-variations of rainfall frequency and intensity, where the slope is a hydrological sensitivity determined by the dryness and storage indices and the intercept is a forcing term associated with changes in moisture convergence, potential evapotranspiration, and effective water-storage capacity. While a given relative change in either rainfall frequency or intensity produces an identical relative change in the mean rate, rainfall intensity additionally influences the runoff coefficient by altering terrestrial water storage relative to rainfall depth. This means frequency and intensity have different impacts on the water cycle, allowing the frequency--intensity slope to depart from -1. Analysis of long-term MOPEX records shows that the forcing term is dominated by moisture convergence and that the frequency--intensity relation becomes steeper from wet to dry regimes, consistent with the slope predicted by the theory. The framework provides a physical interpretation of the observed negative covariation between precipitation frequency and intensity and clarifies the roles of hydrological partitioning and atmospheric moisture supply in their responses to warming.

发表机构

• Nanjing University of Information Science and Technology（南京信息工程大学）
• Princeton University（普林斯顿大学）

机构由 AI 辅助整理，请以论文原文为准。

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14 pages, 5 figures