Uncertainty in the relationship between climate forcing and hydrological response in UK catchments
Uncertainty in the relationship between climate forcing and hydrological response in UK catchments
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DOI：
10.5194/hess-15-897-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Arnell, N. W.
中科院分区：
文献类型：
--
作者：
Arnell, N. W.
本文评估了英国集水区样本中气候强迫量（以全球平均温度变化为指标）与水文响应之间的关系。它从IPCC AR 4评估的21个气候模式的集合中构建了代表全球平均温度不同变化的气候情景。结果显示，21个气候模型之间的影响范围相当大，例如，全球平均温度上升2摄氏度时，夏季径流的变化在-40%和+20%之间。有证据表明，聚类的结果，特别是在夏季径流量和低流量指标的预计变化，这意味着合奏平均值是不是一个适当的广义指标的影响，响应的标准差不足以消除不确定性。因此，水文影响的不确定性最好通过考虑多种气候情景下响应分布的形状来表征。对于某些气候模式模式和某些集水区，也有证据表明，线性气候变化强迫产生非线性水文影响。对于大多数变量和集水区而言，气候变化的影响明显高于自然的多年变化的影响，全球平均气温上升超过1摄氏度，但集水区之间存在差异。根据集合中所代表的情景，北方高地集水区的气候变化影响将在高流量指标中最快显现，但在南方集水区，影响将在夏季和低流量指标中最快显现。由于水文模型参数化的不确定性，不同气候模型模式之间的响应不确定性大大大于范围。
This paper assesses the relationship between amount of climate forcing - as indexed by global mean temperature change - and hydrological response in a sample of UK catchments. It constructs climate scenarios representing different changes in global mean temperature from an ensemble of 21 climate models assessed in the IPCC AR4. The results show a considerable range in impact between the 21 climate models, with - for example - change in summer runoff at a 2 degrees C increase in global mean temperature varying between -40% and +20%. There is evidence of clustering in the results, particularly in projected changes in summer runoff and indicators of low flows, implying that the ensemble mean is not an appropriate generalised indicator of impact, and that the standard deviation of responses does not adequately characterise uncertainty. The uncertainty in hydrological impact is therefore best characterised by considering the shape of the distribution of responses across multiple climate scenarios. For some climate model patterns, and some catchments, there is also evidence that linear climate change forcings produce non-linear hydrological impacts. For most variables and catchments, the effects of climate change are apparent above the effects of natural multi-decadal variability with an increase in global mean temperature above 1 degrees C, but there are differences between catchments. Based on the scenarios represented in the ensemble, the effect of climate change in northern upland catchments will be seen soonest in indicators of high flows, but in southern catchments effects will be apparent soonest in measures of summer and low flows. The uncertainty in response between different climate model patterns is considerably greater than the range due to uncertainty in hydrological model parameterisation.