Multiscale prediction of groundwater response to extreme events

地下水动态是最大限度地减少极端气象事件（干旱或洪水）对生态、社会和经济影响并提高抵御能力的关键。地下水行为的时间动态，由当地天气和补给模式驱动，是很好的理解。然而，有一些较慢的全球气候振荡对陆地水循环有重大影响，而且人们几乎不了解它们（由不饱和带的作用介导）如何影响地下水长期储存动态，也不了解它们对预测干旱风险可能产生的后果。以前有限的工作，包括克兰菲尔德和英国地质调查局之间的工作，已经确定了大规模海洋-大气遥相关模式（如北大西洋涛动和地下水位）之间存在潜在的重要时间关系。Holman等人（2009,2011）利用小波技术研究了三个长期记录的白垩井中大尺度海洋-大气遥相关与地下水位之间的时空相互作用，而Folland等人（2014）基于两个长期地下水位记录发现了La Niña事件与英国低地一些主要多年地下水干旱事件冬季降水不足之间潜在因果关系的证据。该项目将通过结合先进的统计方法、广泛的时空（包括气候、气象、水文地质）数据集和地下水模型来进一步分析这些关系，从而扩展早期的工作。这将有助于改进对地下水位对极端事件（特别是干旱）的反应的预测和管理，以及对地表水系统和水文生态的连锁反应。这项研究将集中在英国和更广泛的欧洲的大量钻孔上，在那里可以获得长期的地下水位数据，以了解不同含水层或气候区域之间的敏感性差异，从而了解干旱的风险。

Groundwater dynamics are key to minimising ecological, societal and economic impacts of, and driving resilience to, extreme meteorological events (drought or flooding). The temporal dynamics of groundwater behaviour, driven by local weather and recharge patterns, are well understood. However, there are slower, global climate oscillations which have a significant impact on the terrestrial water cycle, and for which there is almost no understanding of either how they (mediated by the role of the unsaturated zone) affect long-term groundwater storage dynamics nor what the consequences may be for predicting the risk of drought. Limited previous work, including between Cranfield and the British Geological Survey, has identified that there are potentially significant temporal relationships between large-scale ocean-atmosphere teleconnection patterns such as the North Atlantic Oscillation and groundwater levels. Holman et al (2009, 2011) used wavelet techniques to investigate spatio-temporal interactions between large scale ocean-atmosphere teleconnections and groundwater levels in three chalk boreholes with long term records, while Folland et al. (2014) found evidence for potential causal relationships between La Niña episodes and winter rainfall deficits in some major multi-annual groundwater drought episodes in the English lowlands based on two long groundwater level records. This project will seek to expand on this earlier work by combining advanced statistical methods, extensive spatiotemporal (including climatological, meteorological, hydrogeological) datasets and groundwater modelling to further analyse these relationships. This will enable improved prediction and management of groundwater level response to extreme events (particularly droughts), and the knock-on effects on surface water systems and hydroecology. The research will focus on a larger number of boreholes across the UK and more broadly in Europe where long-term groundwater level data are available to understand the differences in sensitivity between different aquifers or climatological areas and hence risk of drought.