A Weather‐Regime‐Based Stochastic Weather Generator for Climate Vulnerability Assessments of Water Systems in the Western United States
A Weather‐Regime‐Based Stochastic Weather Generator for Climate Vulnerability Assessments of Water Systems in the Western United States
复制标题
DOI：
10.1029/2018wr024446
复制
发表时间：
2019-08
影响因子：
5.4
通讯作者：
S. Steinschneider;P. Ray;Saiful Haque Rahat;J. Kucharski
中科院分区：
文献类型：
--
作者：
S. Steinschneider;P. Ray;Saiful Haque Rahat;J. Kucharski
基于脆弱性的框架越来越多地用于更好地了解气候变化下的水系统性能。这项工作推进了随机天气发生器在气候脆弱性评估中的使用，这些天气发生器根据区域大气流动模式（即，天气状况）以全球尺度气候特征为条件。该模型是半参数设计的，包括（1）用于天气状况模拟的非齐次马尔可夫链;（2）用于多变量，多地点天气模拟的块自举和高斯copula;以及（3）施加热力学和动力学气候变化的模块，包括克劳修斯-克拉珀龙降水定标，高度依赖变暖和厄尔尼诺-南方涛动（ENSO）的移动动力学。通过这种方式，该模型可以用来评估气候对水系统的影响的基础上的动力学和热力学气候变化的假设。该模型是为加州图奥勒米河流域的冷季气候开发和测试的，但广泛适用于整个美国西部。结果表明，8个天气制度施加强烈的影响当地的气候在Tuolumne盆地。模型模拟充分地保留了各站点降水和温度的许多历史统计数据，包括平均值、方差、偏差和极值。年降水量和温度分布有些不均匀，降水时段统计有1 - 2天的负偏差。对于未来气候的模拟，该模型可以生成一系列克劳修斯-克拉珀龙尺度关系和高度依赖变暖模式。模式模拟还表明，图奥勒米气候对ENSO变率变化的反应是温和的。
Vulnerability‐based frameworks are increasingly used to better understand water system performance under climate change. This work advances the use of stochastic weather generators for climate vulnerability assessments that simulate weather based on patterns of regional atmospheric flow (i.e., weather regimes) conditioned on global‐scale climate features. The model is semiparametric by design and includes (1) a nonhomogeneous Markov chain for weather regime simulation; (2) block bootstrapping and a Gaussian copula for multivariate, multisite weather simulation; and (3) modules to impose thermodynamic and dynamical climate change, including Clausius‐Clapeyron precipitation scaling, elevation‐dependent warming, and shifting dynamics of the El Niño–Southern Oscillation (ENSO). In this way, the model can be used to evaluate climate impacts on water systems based on hypotheses of dynamic and thermodynamic climate change. The model is developed and tested for cold‐season climate in the Tuolumne River Basin in California but is broadly applicable across the western United States. Results show that eight weather regimes exert strong influences over local climate in the Tuolumne Basin. Model simulations adequately preserve many of the historical statistics for precipitation and temperature across sites, including the mean, variance, skew, and extreme values. Annual precipitation and temperature are somewhat underdispersed, and precipitation spell statistics are negatively biased by 1‐2 days. For simulations of future climate, the model can generate a range of Clausius‐Clapeyron scaling relationships and modes of elevation‐dependent warming. Model simulations also suggest a muted response of Tuolumne climate to changes in ENSO variability.