Correcting precipitation feature location in general circulation models
Correcting precipitation feature location in general circulation models
复制标题
修正大气环流模型中的降水特征位置
DOI：
10.1002/2014jd022357
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Allen
中科院分区：
文献类型：
--
作者：
A. A. Levy;M. Jenkinson;W. Ingram;M. Allen
有很多证据表明，降水对全球变暖的反应包括潮湿地区变得更潮湿，干燥地区变得更干燥。这提出了挑战的解释预测从大气环流模式（GCM）有很大的偏见，在降水特征的位置。虽然改进GCM模拟的降水是最理想的解决办法，但适应和减缓决策必须利用现有的模型。许多技术已被开发出来，以纠正网格点降水强度的偏差，但很少被引入到纠正位置偏差。在这里，我们描述了一种新的技术，用于校正气候降水特征的空间和季节位置。我们设计这种技术，尊重问题的几何形状（球形空间尺寸，循环季节），同时保存降水强度，或综合降水量。我们讨论了该技术的数学基础，并探讨其在不同制度的行为。我们发现，所产生的翘曲平滑地依赖于最有影响力的参数，这决定了平滑度和拟合度之间的平衡。我们表明，该技术是能够消除一半以上的RMS误差模型的气候，获得一致的更好的结果时，保存综合降水。为了证明新技术改善模拟降水变化的能力，我们将我们的转换应用于历史异常，并表明对于两种类型的偏差，相对于GPCP的异常，RMS误差减少了约10%。这验证了降水变化的误差可以通过校正GCM气候学中的潜在位置误差来减少。
There is much evidence that precipitation responses to global warming involve wet regions becoming wetter and dry regions drier. This presents challenges for the interpretation of projections from general circulation models (GCMs) which have substantial biases in the location of precipitation features. While improving GCM simulated precipitation is the most desirable solution, adaptation and mitigation decisions must be made with the models already available. Many techniques have been developed to correct biases in grid point precipitation intensities, but few have been introduced to correct for location biases. Here, we describe a new technique for correcting the spatial and seasonal location of climatological precipitation features. We design this technique to respect the geometry of the problem (spherical spatial dimensions, with cyclic seasons), while conserving either precipitation intensities, or integrated precipitation amount. We discuss the mathematical basis of the technique and investigate its behaviour in different regimes. We find that the resulting warps depend smoothly on the most influential parameter, which determines the balance between smoothness and closeness of fit. We show that the technique is capable of removing more than half the RMS error in a model's climatology, obtaining consistently better results when conserving integrated precipitation. To demonstrate the ability of the new technique to improve simulated precipitation changes, we apply our transformations to historical anomalies and show that RMS error is reduced relative to GPCP's anomalies by approximately 10% for both types of warp. This verifies that errors in precipitation changes can be reduced by correcting underlying location errors in a GCM's climatology.
影响因子：
5.1
作者：
Jones, C. D.;Hughes, J. K.;Zerroukat, M.
通讯作者：
Zerroukat, M.
通过校正 GCM 中的特征位置来提高外部降水影响的可检测性
DOI：
10.1002/2014jd022358
发表时间：
2014
期刊：
Atmospheres
影响因子：
--
作者：
Levy A
通讯作者：
Levy A