Land use, climate change and water availability: preliminary modelling of impacts of climate change and land use change on groundwater recharge for England and Wales
Land use, climate change and water availability: preliminary modelling of impacts of climate change and land use change on groundwater recharge for England and Wales
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土地利用、气候变化和水资源供应：气候变化和土地利用变化对英格兰和威尔士地下水补给影响的初步模拟
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
A. Hughes
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文献类型：
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作者：
M. Mansour;A. Hughes
为了研究土地利用和气候变化如何影响潜在的补给，来自未来流量和地下水位（FFGWL）项目的11个区域气候模型（RCMs）的降雨和温度数据已被输入补给模型ZOODRM。这为整个英格兰和威尔士的三个时间段（2020年代，2050年代和2080年代）提供了潜在的补给。与此相关联，历史降雨量和潜在蒸发时间序列已运行的历史和“极端假设”的土地利用变化。使用不同的土地覆盖图（LCM）数据集（LCM 2000和LCM 2007）以及三种情景：所有耕地，所有草地和所有森林，运行补给模型。通过将50%的一种土地用途转换为另一种土地用途，对土地使用的一种更微妙的变化进行了调查，例如耕地到森林。
这项工作是作为抽象改革（AR）过程的一部分进行的，这是一个Defra领导的过程，旨在制定一个修订的抽象许可制度。为了与AR过程保持一致，使用了AR试点研究中使用的集水区（Dee、Ely-Ouse、Hampshire Avon、Stour、Tees、Trent和Derwent）。此外，还增加了泰晤士河流域，并总结了英格兰和威尔士的结果。泰晤士河流域的结果产生了异常值，这些值被认为与流域的大小、形状和方向有关。为了研究方向的影响，还研究了两个东西向和两个南北向的条带。结果已被提交为长期平均补给和箱形图的绝对值和修改后的运行和其basecase（历史模拟）之间的差异的差异图。
所选择的集水区有一系列的大小，并位于全国各地不同的气候条件。对气候变化的响应反映了这一点，补给量的增加或减少取决于输入数据和时间段所使用的RCM。可按流域进行以下概括：
Dee -一般情况下，随着时间段内充电量的增加，充电量会降低
Ely-Ouse -在整个时间段内，充电量略有增加
Hampshire Avon -变化取决于RCM;在时间段内无显著变化
Stour -减少充电
充电减少-通过时间片减少充电
泰晤士河-变化取决于RCM; 21世纪80年代补给增加的显著离群值
Trent -变化取决于RCM;通过时间片增加充电
充电乌斯克-增加充电;在时间片上保持一致
就土地利用变化的影响而言，由于历史土地利用（2000年LCM和2007年LCM之间）的微妙“真实的变化”而产生的变化很小，尽管在当地很重要。预计极端的土地利用变化将导致重大变化，但这些情景不太可能实现。对于Dee、Hampshire Avon、Tees和乌斯克，由于土地利用变化和气候变化引起的补给变化相当，对于Ely-Ouse和Trent，由于土地利用变化引起的补给变化小于气候变化引起的补给变化，对于Stour和英格兰和威尔士，整个变化较大。通过交换不同的土地使用类型，即耕地到林地，进一步研究了这一点。这表明变化要小得多，与气候变化相比也不那么重要。
模拟工作要解决的最初问题涉及相对于土地使用变化而言的气候变化引起的补给的相对变化。把英格兰和威尔士作为一个整体，那么由于土地利用变化而引起的补给变化的顺序是：社会经济土地利用（LCM 2000 w.r.t. LCM 2007）小于空间替换小于批发替换（即英格兰和威尔士的所有一种土地使用类型）。比较
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这些变化与气候变化引起的变化的幅度表明，与气候变化有关的补给变化福尔斯属于土地利用变化引起的变化范围。然而，由于使用不同的区域协调机制的补给变化与土地利用变化的总体变化是可比的。
建议进一步开展以下工作：
了解用于输入FFGWL区域气候模型的气候模型，以及改进的“阻塞高压”（大西洋缓慢移动的压力系统）造成的干旱表示。
在模型中使用国家生态系统评估土地使用情景，与气候变化运行的量化进行比较。
将可能产生的补给与其他补给模型（例如顾问为环境署或出版文献中产生的模型）结合起来，并/或产生水平衡，以帮助验证量化的补给。
* 对结果进行进一步分析，例如每月总结潜在的补给，并分析这种情况在每个时间段和跨流域的变化。
3.量化结果中的不确定性。
To investigate how land use and climate change can affect potential recharge, rainfall and temperature data from 11 Regional Climate Models (RCMs) from the Future Flow and Groundwater Level (FFGWL) project have been fed into the recharge model ZOODRM. This has produced potential recharge for the whole of England and Wales for three time slices (2020s, 2050s and 2080s). Allied to this, the historic rainfall and potential evaporation time series have been run for both historic and “extreme assumed” land use change. The recharge model was run using different land cover mapping (LCM) datasets (LCM2000 and LCM2007) as well as three scenarios: all arable, all grass and all forested. A more subtle change in land use was investigated by swapping 50% of one land use for another, e.g. arable to forested.
This work has been undertaken as part of the Abstraction Reform (AR) process, a Defra led process which aims to produce a revised abstraction licencing regime. To provide consistency with the AR process the catchments used in the AR pilot study have been used (Dee, Ely-Ouse, Hampshire Avon, Stour, Tees, Trent and Derwent). In addition, the Thames Basin has been added and the results summarised for England and Wales. The results for the Thames Basin produced anomalous values which were thought to be related to the size, shape and orientation of the catchment. To investigate the impact of orientation, then two east-west and two north-south strips were also examined. The results have been presented as both difference maps of long-term average recharge and box and whisker plots for both the absolute values of recharge and the differences between the modified run and its basecase (historical simulation).
The catchments chosen have a range of sizes and are located in different climate conditions around the country. The response to climate change reflects this with recharge decreasing or increasing depending on the RCM used for the input data and time slice. The following generalisations by catchment can be made:
Dee – lower recharge in general with increasing recharge through the time slices
Ely-Ouse – very slight increase in recharge which increases through the time slices
Hampshire Avon –variation depending on the RCM; no significant change across the time slices
Stour – reduction in recharge
Tees – reduction in recharge which decreases through time slices
Thames – variation depending on the RCM; significant outliers with increased recharge in the 2080s
Trent – variation depending on the RCM; increased recharge through the time slices
Usk – increased recharge; consistent over time slices
In terms of the effect of land use change then variation due to subtle ‘real changes’ in historic land use (between LCM 2000 and LCM 2007) is small, although locally significant. Extremes of land use change are predicted to result in significant change but these scenarios are very unlikely to be realised. For the Dee, Hampshire Avon, Tees and the Usk the change in recharge due to land use change and due to climate change is comparable, for the Ely-Ouse and Trent the change in recharge less due to land use change than for climate change and for the Stour and England and Wales as a whole the change is greater. This was investigated further by swapping out different land use types, i.e. arable to forested. This showed much less variation, and was less significant in comparison with climate change.
The original question that the modelling work was to address relates to the relative changes in recharge with respect to climate change as opposed to land use change. Taking England and Wales as a whole then the order of change in recharge due to land use variation is: socio-economic land use (LCM2000 w.r.t. LCM2007) is less than spatial replacement is less than wholesale replacement (i.e. all one land use type for England and Wales). Comparing the
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magnitude of these changes with those resulting from climate change show that variation of recharge related to climate change falls within the range of that resulting from land use change. However, the variation of recharge due to the use of different RCMs is comparable with the overall variation of land use change.
Further work is recommended as follows:
Understand the climate models used to feed into the FFGWL RCMs alongside an improved representation of droughts resulting from “blocking highs” – slow moving pressure systems in the Atlantic.
Use of National Ecosystem Assessment land use scenarios in the model to compare with the quantification of climate change runs.
Combine the potential recharge produced with other recharge models (e.g. those produced for the Environment Agency by consultants or in the published literature) and/or produce water balances to help validate the recharge quantified.
Undertake further analysis of the results, such as monthly summaries of potential recharge and analyse how this changes for each time slice and across catchments.
Quantify the uncertainty in the results.