NCC_CGCM模式的我国夏季降水集合预报方法效果评估及改进

通过对国家气候中心全球海气耦合模式(NCC_CGCM)1983～2006年48个不同初值样本的我国夏季降水预报(回报)、等权重集合预报及二次非线性订正预报的评估效果比较,其中订正预报的平均效果比等权重集合预报的平均效果好,但总体平均预报效果都不高.在评估中发现,48个样本在不同地区的预报效果的差异显著,正相关显著区域出现的位置各不相同,有的样本出现在江南,有的出现在东北,还有的出现在黄淮等地,因此提出了用历史回报的相关系数构建新的集合预报.试验表明,新集合预报的平均效果优于等权重集合预报、二次非线性订正预报和业务系统中现有的集成方法.

EVALUATION AND IMPROVEMENT OF SUMMER PRECIPITATION ENSEMBLE FORECAST BY THE NCC-CGCM MODEL

The prediction of summer precipitation by the NCC_CGCM model with 48 samples in China(160 stations) from 1983 to 2006 is assessed.It's found from the comparison of the equal weight consensus with the forecast amendment(with the Ps,ACC grade of NCC and Ks grade commended by WMO) that the average effect of forecast amendment of quadratic non-linear of 48 samples is better than that of equal weight ensemble forecast but is still poorer than the best of the individual samples,The 48 samples have different prediction results in different areas and the average effect of the new ensemble forecast designed by ACC is better than the equal weight ensemble forecast,forecast amendment and exiting ensemble method in the operation system.