Improved confidence in climate change projections of precipitation evaluated using daily statistics from the PRUDENCE ensemble
Improved confidence in climate change projections of precipitation evaluated using daily statistics from the PRUDENCE ensemble
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DOI：
10.1007/s00382-008-0446-y
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发表时间：
2009-06
期刊：
影响因子：
4.6
通讯作者：
F. Boberg;P. Berg;P. Thejll;W. Gutowski;J. Christensen
中科院分区：
文献类型：
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作者：
F. Boberg;P. Berg;P. Thejll;W. Gutowski;J. Christensen
通过用概率密度函数 (PDF) 表征降水，将欧洲框架项目 PRUDENCE 的区域气候模型模拟集合与欧洲气候评估数据集中观测到的每日降水量进行比较。基于归一化概率密度函数的重叠，确定了强有力地描述给定区域以及跨区域控制期（1961-1990）观察结果的模型，然后使用基于替换引导的方法进行验证。我们还使用所有可用模型比较了情景期（2071-2100）和控制期降水量之间的差异。通过使用量化整个 PDF 偏差的指标，我们发现场景期间较密集的事件对总降水量的贡献明显显着增加，而小降水天数的贡献明显显着减少。这种变化经过测试是稳健的，并且在所有模型和所有子区域中都有发现。我们发现，随着变暖程度的增加，PDF 差异的增加可被检测到，从而成为气候变化水平的相对指标。此外，当气候变化没有表现出任何显着变化时，交叉点将归一化降水谱的贡献减少与增加分开，这符合假设对降水谱进行简单分析拟合的预期。
An ensemble of regional climate modelling simulations from the European framework project PRUDENCE are compared across European sub-regions with observed daily precipitation from the European Climate Assessment dataset by characterising precipitation in terms of probability density functions (PDFs). Models that robustly describe the observations for the control period (1961–1990) in given regions as well as across regions are identified, based on the overlap of normalised PDFs, and then validated, using a method based on bootstrapping with replacement. We also compare the difference between the scenario period (2071–2100) and the control period precipitation using all available models. By using a metric quantifying the deviation over the entire PDF, we find a clearly marked increase in the contribution to the total precipitation from the more intensive events and a clearly marked decrease for days with light precipitation in the scenario period. This change is tested to be robust and found in all models and in all sub-regions. We find a detectable increase that scales with increased warming, making the increase in the PDF difference a relative indicator of climate change level. Furthermore, the crossover point separating decreasing from increasing contributions to the normalised precipitation spectrum when climate changes does not show any significant change which is in accordance with expectations assuming a simple analytical fit to the precipitation spectrum.