Spatio-temporal modelling of the status of groundwater droughts
Spatio-temporal modelling of the status of groundwater droughts
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DOI：
10.1016/j.jhydrol.2018.07.009
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发表时间：
2018-09
影响因子：
6.4
通讯作者：
B. Marchant;J. Bloomfield
中科院分区：
文献类型：
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作者：
B. Marchant;J. Bloomfield
一个经验（地理）统计建模计划的开发，以解决模拟地下水干旱的严重性和分布的挑战，因为它们的空间和时间的异质性，并给出典型的高度不规则的地下水位观测的空间和时间。该计划是测试使用GWL测量948观测钻孔在白垩含水层（英国），估计每月地下水干旱状态从1960年到2013年。对于每个钻孔，使用经验混合模型模拟每月GWL，其中固定效应基于对当地月降水量应用脉冲响应函数。使用标准化地下水指数（SGI）和跨含水层内插的每月SGI值对模拟GWL进行标准化，以生成54年来粉笔SGI干旱状况的空间分布月度地图。混合模型包括较少的参数比可比的集总参数地下水模型，同时解释相似的比例（超过65%）的GWL变化。此外，经验建模方法，使预测的GWL和SGI值的置信区间估计，而不需要有关集水区或含水层参数的先验信息。模拟方案的结果显示了三个主要的多年干旱事件（1975-1976年; 1988-1992年; 2011-2012年）。他们同意以前记录的地下水干旱的分析，同时首次提供了一个系统的，空间上连贯的事件特征。该计划是适合使用在近真实的时间，提供短期的地下水干旱状况的预测，如果合适的预测的驱动气象。
An empirical (geo)statistical modelling scheme is developed to address the challenges of modelling the severity and distribution of groundwater droughts given their spatially and temporally heterogeneous nature and given typically highly irregular groundwater level observations in space and time. The scheme is tested using GWL measurements from 948 observation boreholes across the Chalk aquifer (UK) to estimate monthly groundwater drought status from 1960 to 2013. For each borehole, monthly GWLs are simulated using empirical mixed models where the fixed effects are based on applying an impulse response function to the local monthly precipitation. Modelled GWLs are standardised using the Standardised Groundwater Index (SGI) and the monthly SGI values interpolated across the aquifer to produce spatially distributed monthly maps of SGI drought status for 54 years for the Chalk. The mixed models include fewer parameters than comparable lumped parameter groundwater models while explaining a similar proportion (more than 65%) of GWL variation. In addition, the empirical modelling approach enables confidence bounds on the predicted GWLs and SGI values to be estimated without the need for prior information about catchment or aquifer parameters. The results of the modelling scheme are illustrated for three major episodes of multi-annual drought (1975–1976; 1988–1992; 2011–2012). They agree with previous documented analyses of the groundwater droughts while providing for the first time a systematic, spatially coherent characterisation of the events. The scheme is amenable to use in near real time to provide short term forecasts of groundwater drought status if suitable forecasts of the driving meteorology are available.