区域气候模拟研究中的物理集合技术

THE PHYSICAL ENSEMBLE TECHNIQUE OF THE REGIONAL CLIMATE SIMULATION

文中介绍了基于MM 5有限区域模式的物理集合构造方法 ,通过对模式中的 5种物理过程加以扰动、组合而得到一个有 19个成员的物理集合系统 ,并用其对 1998年夏季发生在中国东部地区的异常洪涝天气气候特征进行了模拟研究。以集合预报的 3种基本释用方法 ,对集合模拟产生的大量输出结果作了细致的分析 ,发现在区域气候模拟中 ,引入物理集合是可行的 ;它为区域气候数值研究提供了更多的手段和信息 ;集合系统存在的不足之处在于 :集合成员间离散程度不足、集合模拟范围较狭窄 ,这使得离差对误差的实际预报能力低于潜在预报能力 ,也使集合概率预报的精度降低。

The five physical processes used in the limited area model MM5 are disturbed to form a physical ensemble system of 19 members. The abnormal synoptic situation and heavy rain occurred in summer of 1998 in Eastern China was simulated with this physical ensemble system. The outputs from the ensemble simulation are analyzed using the three basic interpretational methods commonly used in the ensemble forecast; the consequence is that it is practicable to introduce ensemble technique in regional climate study. The ensemble technique appends new methods and additional information to regional climate simulation as well. However, there are still some flaws in the ensemble system, the ensemble members are not diverse enough and the range of ensemble simulation is rather narrow, which not only lowers the accuracy of probability forecast of deviation but also leads to the actual forecast capability being inferior to the potential one.