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Hydrological extremes and feedbacks in the changing water cycle

变化的水循环中的水文极端情况和反馈

基本信息

批准号：
NE/I006656/1
负责人：
Richard Chandler
金额：
$ 23.48万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FI006656%2F1
关键词：
Hydrological extremes feedbacks changing water

项目摘要

The prospect of significant climate change over the next decades means that society must urgently face up to the implications for the changing water cycle, in particular increasing risks from extreme floods and droughts. Guidance for policy-makers to support adaptation to these risks and to support mitigation strategies to combat climate change is urgently required. However, the ability of climate scientists and hydrologists to predict the possible magnitudes of floods and droughts, and the frequency with which they are expected to occur, is still limited. This is due largely to gaps in knowledge of how best to use available data and models; of particular concern is the limited ability of climate and hydrological models to produce realistic extremes and changing hydrological behaviour. For example, regional climate models produce data which often requires to be downscaled to finer resolutions, but questions arise about what properties of the downscaled data are critical and how the downscaling should be done. As another example, drought planning requires inter-annual and inter-regional rainfall and evaporation to be represented accurately, however there is little guidance about how this can best be achieved under future climate using available models. In addition, there are weaknesses in the simulation of hydrology (for example, groundwater storage, river flows and evaporation) which act as hurdles to development of next generation climate models; in particular models currently used to simulate feedbacks from the earth surface to the atmosphere neglect important hydrological processes. This proposal will produce the science and models needed to address these questions, integrating climate and hydrological science to take impact modelling beyond the current state of the art. Specifically, the proposal: 1. exploits current generation climate science and statistical methods to improve and enhance projections of potential change in hydrologically-relevant metrics over a time-scale of 10 to 60 years, in particular extremes of heavy precipitation and drought; 2. builds on the analysis of historical data to improve scientific understanding and develop innovative methods for the modelling of extremes and non-stationarity in the hydrological response to climate variability; 3. seeks to improve the representation of hydrological processes in land surface models, in particular, the enhanced modelling of surface and subsurface processes for simulation of land-atmosphere feedbacks. In addressing these gaps in knowledge, the proposed project will cross all four themes of NERC's Changing Water Cycle programme: land-atmosphere interactions; precipitation modelling; understanding of change; and innovative ways to assess consequences. Case studies will include the Thames catchment and the Eden catchment. These catchments are broadly representative of lowland and upland UK with substantial climate and hydrological datasets from NERC and DEFRA-EA experimental programmes. This project will consider local to catchment scales, with the view that the resulting science and models will ultimately be integrated into global scale models. The main project outputs will be: 1) improved quantification of future variability and extremes of precipitation and evaporation over hydrologically relevant scales in the UK; 2) improved models of the hydrological water cycle response to these extremes, with the explicit inclusion of non-stationary conditions; 3) the inclusion of earth-atmosphere feedback processes and their effects in climate models, in particular the recognition and inclusion of unsaturated zone and groundwater storage and discharge. In all cases, new modelling tools will be developed to test the ideas of meteo-hydrological functioning.

未来几十年气候将发生重大变化的前景意味着社会必须紧急面对水循环变化的影响，特别是极端洪水和干旱带来的日益增加的风险。迫切需要为决策者提供指导，以支持适应这些风险，并支持应对气候变化的缓解战略。然而，气候科学家和水文学家预测洪水和干旱可能的规模以及预计发生的频率的能力仍然有限。这主要是由于在如何最好地利用现有数据和模型方面存在知识差距;特别令人关切的是，气候和水文模型产生现实极端情况和不断变化的水文行为的能力有限。例如，区域气候模型产生的数据往往需要缩小尺度以获得更精细的分辨率，但缩小尺度的数据的哪些特性是关键的以及如何缩小尺度的问题就出现了。另一个例子是，干旱规划需要准确地表示年际和区域间的降雨量和蒸发量，但对于如何利用现有模型在未来气候下最好地实现这一点，几乎没有指导。此外，水文模拟（例如地下水储存、河流流量和蒸发）也有弱点，这是开发下一代气候模型的障碍;特别是目前用于模拟从地球表面到大气的反馈的模型忽视了重要的水文过程。该提案将产生解决这些问题所需的科学和模型，整合气候和水文科学，使影响建模超越目前的最新水平。利用当代气候科学和统计方法，改进和加强对10至60年时间尺度内水文相关指标潜在变化的预测，特别是极端的强降水和干旱; 2.在分析历史数据的基础上，提高科学认识，并制定创新方法，对水文对气候变化的反应中的极端和非平稳性进行建模; 3.旨在改进陆面模型中水文过程的表现，特别是改进模拟陆-气反馈的地表和次表层过程模型。在解决这些知识差距时，拟议的项目将跨越NERC的水循环变化方案的所有四个主题：陆地-大气相互作用;降水建模;对变化的理解;以及评估后果的创新方法。案例研究将包括泰晤士河流域和伊甸园流域。这些集水区广泛代表了英国的低地和高地，并具有大量来自NERC和DEFRA-EA实验方案的气候和水文数据集。该项目将考虑从地方到流域的尺度，以期最终将由此产生的科学和模型纳入全球尺度的模型。项目的主要产出将是：1）改进对联合王国水文相关尺度上降水和蒸发的未来变异性和极端情况的量化; 2）改进对这些极端情况的水文水循环响应模型，明确纳入非平稳条件; 3）在气候模式中纳入地球-大气反馈过程及其影响，特别是确认和列入非饱和带和地下水储存和排放。在所有情况下，将开发新的建模工具，以测试气象水文功能的想法。