自忆谱模式制作中期天气预报的试验

资助项目:

国家自然科学基金项目49675262

NUMERICAL WEATHER PREDICTION WITH SELF-MEMORIAL SPECTRAL MODEL

摘要: 基于大气自忆性观点, 引进记忆函数, 可构造一个差分-积分方程; 称之为自忆性方程; 给出了此方程的球谐表达式及其离散计算公式.以T42L9谱模式为动力核, 建立了一个全球自忆T42谱模式 (SMT42).用实际资料进行了逐日至15天积分试验计算, 表明对于500 hPa中期数值天气预报, SMT42比T42的均方根误差小得多, 同时SMT42对距平相关系数也有所提高, 这为中期数值天气预报提供了一种有潜力的新途径.
- 中期天气预报;
- 数值谱模式;
- 自记忆
Abstract: Applying a memory concept to numerical weather prediction and introducing a memorial function, an appropriate difference-integral equation which is called a selfmemorization one has been formulated. Meanwhile the spherical harmonic representation of the equation is drieved too. Setting up and solving the equation establish a new approach of numerical weather prediction. Using T42L9 spectral model as a dynamic kernel, a global self-memorial T42 model (SMT42) was setup, with which several cases of 15-day integration experiments were carried out. Compared with T42, SMT42 is much better in 500 hPa forecast in daily up to 15 days, whose root mean square error (RMSE) is significantly reduced.
- Medium-range weather prediction;
- Spectral Model;
- Self-memorization

图 1 以T42谱模式 (虚线) 与SMT42谱模式 (实线) 所作的 500 hPa高度预报的均方根误差 (S) 全球平均

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图 2 1990年8月31日500 hPa高度的初始场

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图 3 1990年9月5日500 hPa高度

a) 观测结果; b) T42谱模式的预报; c) SMT42谱模式的预报

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图 4 1990年9月10日500 hPa高度场

(说明同图 3)

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表 1 北半球20°～90°N 500 hPa高度的均方根误差

表 2 南半球20°～90°S 500 hPa高度的均方根误差

表 3 热带20°S～20°N 500 hPa高度的均方根误差

表 4 观测场与预报场之间距平相关系数ρ≥0.6的天数

表 5 逐日距平相关系数的12个月平均值及改进率

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