气象领域极端事件的长程相关性

Long-range correlation of extreme events in meterorological field

利用固定阈值法研究了Lorenz系统极端事件序列的长程相关性特征.研究结果表明:不同阈值标定的极端事件序列具有长程相关性,且标度指数α比较接近,但都比Lorenz系统略小.不同的初值对极端事件序列的长程相关性影响不大,即对初值不敏感性,但Lorenz系统的长程相关性随着控制参数的增大而明显减弱.通过与高斯白噪声序列对比研究发现,Lorenz系统极端事件序列具有较好的记忆性特征.最后采用国家气候中心194个测站1957年—2004年日最高气温观测资料进行分析,揭示了实际气象要素中存在类似的规律.

The long range correlation of extreme events of the Lorenz system is discussed by using the method of fixed threshold.It turns out that all of the extreme events with different threshold have long range correlation.The scaling exponents are similar,but just smaller than the original series.The long range correlation of extreme events is less effected by the initial value changes,but it decreases distinctly when the parameters increases.The long range correlation of Lorenz system＇s extreme events series has the traits of memory when compared with Gaussian white noise.Finally,we use the maximal day air temperature data of 194 stations between 1957 and 2004,from the National Climate Center of China,to reveal that the similar law exists in the actual meteorological factors.