A stochastic rainfall model for the assessment of regional water resource systems under changed climatic condition
A stochastic rainfall model for the assessment of regional water resource systems under changed climatic condition
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DOI：
10.5194/hess-4-263-2000
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发表时间：
2000-06
影响因子：
6.3
通讯作者：
H. Fowler;C. Kilsby;P. E. O'connell
中科院分区：
文献类型：
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作者：
H. Fowler;C. Kilsby;P. E. O'connell
抽象。建立了一个随机模型，用于天气类型条件化合成日降水量。每日降水量统计在多个站点内的约克郡，英国，与客观的兰姆天气类型（LWT），并用于将该地区分为三个不同的降水子区域。使用方差最小化标准，27个LWT被聚类成三个物理上现实的组或“状态”。一个半马尔可夫链模型被用来合成长序列的天气状态，保持观察到的持久性和转移概率。Neyman-Scott矩形脉冲（NSRP）模型，然后适合每个天气状态，使用定义的夏季和冬季。组合模式再现的关键方面的历史降水制度的时间分辨率下降到每小时一级。人工合成的长降水序列可用于当前和变化的气候条件下水资源系统的敏感性分析。这种方法能够调查天气类型持续性或频率变化的影响。此外，降雨模型统计数据可以改变，以模拟干旱日强度或比例增加的情况，例如，针对个别天气组。将这些数据输入水资源模型，模拟潜在的大气环流变化，将为水资源系统的未来规划提供宝贵的工具。该模型每小时运行的能力也使其能够用于更广泛的水文影响研究，例如河流流量变化、洪水风险估计等。关键词：水资源;气候变化;影响;随机降雨模型;兰姆天气类型
Abstract. A stochastic model is developed for the synthesis of daily precipitation using conditioning by weather types. Daily precipitation statistics at multiple sites within the region of Yorkshire, UK, are linked to objective Lamb weather types (LWTs) and used to split the region into three distinct precipitation sub-regions. Using a variance minimisation criterion, the 27 LWTs are clustered into three physically realistic groups or ‘states'. A semi-Markov chain model is used to synthesise long sequences of weather states, maintaining the observed persistence and transition probabilities. The Neyman-Scott Rectangular Pulses (NSRP) model is then fitted for each weather state, using a defined summer and winter period. The combined model reproduces key aspects of the historic precipitation regime at temporal resolutions down to the hourly level. Long synthetic precipitation series are useful in the sensitivity analysis of water resource systems under current and changed climatic conditions. This methodology enables investigation of the impact of variations in weather type persistence or frequency. In addition, rainfall model statistics can be altered to simulate instances of increased intensity or proportion of dry days for example, for individual weather groups. The input of such data into a water resource model, simulating potential atmospheric circulation changes, will provide a valuable tool for future planning of water resource systems. The ability of the model to operate at an hourly level also allows its use in a wider range of hydrological impact studies, e.g. variations in river flows, flood risk estimation etc. Keywords: water resources; climate change; impacts; stochastic rainfall model; Lamb weather types