Generation of ensemble precipitation forecast from single-valued quantitative precipitation forecast for hydrologic ensemble prediction
Generation of ensemble precipitation forecast from single-valued quantitative precipitation forecast for hydrologic ensemble prediction
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DOI：
10.1016/j.jhydrol.2011.01.013
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发表时间：
2011-03
影响因子：
6.4
通讯作者：
Limin Wu;D. Seo;J. Demargne;James D. Brown;S. Cong;J. Schaake
中科院分区：
文献类型：
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作者：
Limin Wu;D. Seo;J. Demargne;James D. Brown;S. Cong;J. Schaake
可靠和熟练的降水集合预报对于产生可靠和熟练的水文集合预报是必要的。众所周知，一般来说，来自数值天气预报(NWP)模式的原始降水集合预报不是很可靠，对于短期预报，人类预报员为NWP生成的单值定量降水预报(QPF)增加了大量的技能。在本文中，我们描述和评估了一种从单值QPF产生降水集合预报的统计方法。该方法基于观测降水量与单值QPF之间的双变量概率分布。其分布模型为混合型，其中正向实测值与正向预报值之间的关系假定为二元亚高斯分布。我们还描述并比较了一个广义的元高斯模型，该模型通过最小化平均连续排序概率得分来优化模型参数。这些程序的性能是通过使用国家气象局阿肯色州-红色盆地、加利福尼亚州-内华达州和中大西洋河流预报中心服务区选定河流流域的相关和交叉验证数据来评估的。验证结果表明，总体来说，由所提出的方法生成的降水集合是可靠的，并很好地捕捉到了条件单值预报的技巧。
Reliable and skillful precipitation ensemble forecasts are necessary to produce reliable and skilful hydrologic ensemble forecasts. It is well known that, in general, raw precipitation ensemble forecasts from the numerical weather prediction (NWP) models are not very reliable and that, for short-range prediction, human forecasters add significant skill to the NWP-generated single-valued quantitative precipitation forecasts (QPF). In this paper, we describe and evaluate a statistical procedure for producing precipitation ensemble forecasts from single-valued QPFs. The procedure is based on the bivariate probability distribution between the observed precipitation and the single-valued QPF. The distribution is modeled as a mixed-type in which the relationship between the positive observed precipitation and positive forecast precipitation is assumed to be bivariate meta-Gaussian. We also describe and comparatively evaluate a generalized meta-Gaussian model in which the model parameter is optimized by minimizing the mean Continuous Ranked Probability Score. The performance of these procedures is assessed through dependent and cross validation using data for selected river basins in the service areas of the Arkansas-Red Basin, California-Nevada and Middle-Atlantic River Forecast Centers of the National Weather Service. The validation results show that, overall, the precipitation ensembles generated by the proposed procedures are reliable and capture the skill in the conditioning single-valued forecasts very well.