Why Should Ensemble Spread Match the RMSE of the Ensemble Mean?

被引:165
作者
Fortin, V. [1 ]
Abaza, M. [2 ]
Anctil, F. [2 ]
Turcolle, R. [3 ]
机构
[1] Environm Canada, Meteorol Res Div, Dorval, PQ H9P 1J3, Canada
[2] Univ Laval, Dept Genie Civil, Quebec City, PQ G1K 7P4, Canada
[3] Minist Dev Durable, Ctr Expertise Hydr Quebec, Quebec City, PQ, Canada
关键词
GLOBAL ENSEMBLE; FORECASTS; RELIABILITY; SYSTEM; IMPACT; FRANCE;
D O I
10.1175/JHM-D-14-0008.1
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
When evaluating the reliability of an ensemble prediction system, it is common to compare the root-mean-square error of the ensemble mean to the average ensemble spread. While this is indeed good practice, two different and inconsistent methodologies have been used over the last few years in the meteorology and hydrology literature to compute the average ensemble spread. In some cases, the square root of average ensemble variance is used, and in other cases, the average of ensemble standard deviation is computed instead. The second option is incorrect. To avoid the perpetuation of practices that are not supported by probability theory, the correct equation for computing the average ensemble spread is obtained and the impact of using the wrong equation is illustrated.
引用
收藏
页码:1708 / 1713
页数:6
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