Downscaling precipitation using regional climate models and circulation patterns toward hydrology
Downscaling precipitation using regional climate models and circulation patterns toward hydrology
复制标题
利用区域气候模型和水文环流模式降尺度降水
DOI：
10.1029/2010wr009689
复制
发表时间：
2011
影响因子：
5.4
通讯作者：
G. Pegram
中科院分区：
文献类型：
--
作者：
Bárdossy;G. Pegram
本文的目的是定义一种方法来确定合理的估计降雨模拟全球环流模式（GCMs）与区域气候模式（RCMs）。本文介绍和使用两个新的程序，旨在提供信心，在解释这种降雨量估计。其中第一个程序是使用环流模式（CP）来定义观测降雨量和RCM估计降雨量之间的分位数-分位数（Q-Q）转换（CP来自海平面气压（SLP）场，该场是从先前研究中对历史每日天气的再分析中获得的）。在20年的校准期内使用两种降尺度技术推导出Q-Q变换，并在10年的观测期内进行了验证。第二个新的程序是使用双Q-Q变换来估计降雨模式和量从GCM-RCM预测的SLP和降雨场在未来一段时间。这个过程是必要的，因为我们发现每个块体上的CP依赖的降雨频率分布与相应的历史分布出乎意料地不同。每日降雨场比较记录在一个25公里的网格上的莱茵河流域在德国，观察到的每日数据的平均超过网格块，并已估计在同一个网格的RCM值。计算验证期间每个区块记录的年度极值（1）最大日降雨量和（2）最低5%过滤降雨量，以确定RCM捕获对水文应用重要的降雨特征的能力。结论是：（1）这里使用的RCM输出很好地捕捉了CP相关降雨的模式和排序;（2）CP相关的降尺度，加上双Q-Q变换，在验证期间给出了降雨的良好估计;（3）由于RCM提供了与观测分布不同的未来CP相关降雨分布，因此可以判断这些预测，一旦通过双重Q-Q转换进行修改，在水文上是合理的;（4）在莱茵河流域的气候在未来，由RCM模拟，很可能比过去更潮湿。结果表明，这种未来的预测可以谨慎地使用。
The aim of this paper is to define a method for determining reasonable estimates of rainfall modeled by global circulation models (GCMs) coupled with regional climate models (RCMs). The paper describes and uses two new procedures designed to give confidence in the interpretation of such rainfall estimates. The first of these procedures is the use of circulation patterns (CPs) to define quantile‐quantile (Q‐Q) transforms between observed and RCM‐estimated rainfall (the CPs were derived from sea level pressure (SLP) fields obtained from reanalysis of historical daily weather in a previous study). The Q‐Q transforms are derived using two downscaling techniques during a 20 year calibration period and were validated during a 10 year period of observations. The second novel procedure is the use of a double Q‐Q transform to estimate the rainfall patterns and amounts from GCM‐RCM predictions of SLP and rainfall fields during a future period. This procedure is essential because we find that the CP‐dependent rainfall frequency distributions on each block are unexpectedly different from the corresponding historical distributions. The daily rainfall fields compared are recorded on a 25 km grid over the Rhine basin in Germany; the observed daily data are averaged over the grid blocks, and the RCM values have been estimated over the same grid. Annual extremes, recorded on each block during the validation period, of (1) maximum daily rainfall and (2) the lowest 5% of filtered rainfall were calculated to determine the ability of RCMs to capture rainfall characteristics which are important for hydrological applications. The conclusions are that (1) RCM outputs used here are good at capturing the patterns and rankings of CP‐dependent rainfall; (2) CP‐dependent downscaling, coupled with the double Q‐Q transform, gives good estimates of the rainfall during the validation period; (3) because the RCMs offer future CP‐dependent rainfall distributions that are different from the observed distributions, it is judged that these predictions, once modified by the double Q‐Q transforms, are hydrologically reasonable; and (4) the climate in the Rhine basin in the future, as modeled by the RCMs, is likely to be wetter than in the past. The results suggest that such future projections may be used with cautious confidence.
影响因子：
6.8
作者：
AKAIKE, H
通讯作者：
AKAIKE, H
使用水文变量对德国西南部的大气环流模式进行分类
影响因子：
3.7
作者：
A. Bárdossy
通讯作者：
A. Bárdossy