Climatic Asynchrony and Hydrologic Inefficiency Explain the Global Pattern of Water Availability
Climatic Asynchrony and Hydrologic Inefficiency Explain the Global Pattern of Water Availability
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DOI：
10.1029/2022gl101214
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发表时间：
2022-12
影响因子：
5.2
通讯作者：
J. Jawitz;H. Klammler;N. Reaver
中科院分区：
文献类型：
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作者：
J. Jawitz;H. Klammler;N. Reaver
观测到的将降水（P $P$）分配给蒸散量（E $E$）和径流（Q $Q$）的全球模式背后的机制存在争议。我们检验了这样一个假设：气候供水和需求之间的异步性足以解释可用水量的时空变化。我们开发了一个简单的 Q $Q$ 分析模型，该模型由年内供水和需求异步的四个无量纲特征确定。该分析模型填充了网格气候数据，准确预测了全球径流模式，误差范围在全球气候模型独立估计值的 2%–4% 范围内，空间模式与观测结果密切相关 ( R2=0.93 ${R}^{2}=0.93$ )。供需异步假说利用易于测量的气候特征，为可用水量的变化提供了基于物理的解释。该模型揭示了全球几乎每个地区的水预算对气候异步变化的广泛响应。此外，使用全局平均值的分析模型独立地再现了Budyko曲线（R2=0.99 ${R}^{2}=0.99$），为这种广泛使用的经验关系提供了理论基础。
The mechanisms underlying observed global patterns of partitioning precipitation ( P $P$ ) to evapotranspiration ( E $E$ ) and runoff ( Q $Q$ ) are controversially debated. We test the hypothesis that asynchrony between climatic water supply and demand is sufficient to explain spatio‐temporal variability of water availability. We developed a simple analytical model for Q $Q$ that is determined by four dimensionless characteristics of intra‐annual water supply and demand asynchrony. The analytical model, populated with gridded climate data, accurately predicted global runoff patterns within 2%–4% of independent estimates from global climate models, with spatial patterns closely correlated to observations ( R2=0.93 ${R}^{2}=0.93$ ). The supply‐demand asynchrony hypothesis provides a physically based explanation for variability of water availability using easily measurable characteristics of climate. The model revealed widespread responsiveness of water budgets to changes in climate asynchrony in almost every global region. Furthermore, the analytical model using global averages independently reproduced the Budyko curve ( R2=0.99 ${R}^{2}=0.99$ ) providing theoretical foundation for this widely used empirical relationship.