中国年降水气候振动的非线性动力学特征

从观测资料出发,利用反演方法,获得了描述我国17个站年降水气候振动的二阶非线性动力学方程组中的系数,并在无外源强迫的情况下对该非线性动力学方程组作了定性的分析,对17个站的年降水气候振动进行气候模拟试验。结果表明:我国大部分地区的年降水气候振动存在弱的非线性振动特征,17个站的年降水气候振动都可以看作是一个正阻尼的动力系统,在运动变化过程中,自身能量的变化dEdt<0,17个站年降水气候振动的固有频率的变化范围为0.6≤ω0≤1.417,其固有周期的变化范围为10.4≥T≥4.4年。从空间分布特征上可以看到,其固有周期的长短分布有明显的东西向特征。在17个站中,兰州、成都、重庆、南宁、福州、上海、温州地区的年降水气候振动是一个类似于具有渐软弹簧特性的非线性动力系统,而昆明、长春、哈尔滨、北京、广州、西安、厦门、长沙、南京、杭州地区的年降水气候振动是一个类似于具有渐硬弹簧特性的非线性动力系统,从其空间分布特征上看也有东西向特征。全国17个站年降水气候振动的动力系统都存在一个稳定的焦点,在无外源强迫作用时,各站的年降水气候振动将逐渐趋向于各自的稳定的焦点,但都不存在极限环。在仅考虑降水自身振动的情况下,利用我们反演得到的非线性动力学方程对年降水气候振动做模拟,位于内陆地区的模拟情况可以通过显著性水平检验,而靠近海洋的地区模拟效果没有内陆好。这一结果说明在降水气候振动中,靠近海洋地区的外源强迫影响作用比位于内陆地区大。

The Nonlinear Dynamical Features of Annual Precipitation Climate Oscillation in China

According to the observational data,with the application of quadratic dynamical system,we have retrieved the nonlinear dynamical equations that describing the precipitation climate oscillation at 17 stations in China.Then the considering without external forcing, these equations are qualitatively analyzed.Results of the analysis show that most of the annual precipitation climate oscillation system in China exist the weak nonlinear oscillation feature.This system can be seen as a positive damped dynamical system,and its energy transformation is beyond zero.That is to say,without external forcing,the movement of this system could always be wane.The natural period of the system is from 4.4 to 10 years,and its distribution is like a wave from west to east.At the 17 stations,the annual precipitation climate oscillation systems of Lanzhou,Chengdu,Chongqing,Nanning,Shanghai,Fuzhou and Wenzhou are gradual-soft elastic systems.But those of Kunming,Changchun,Haerbing,Beijing,Guangzhou,Xian,Xiamen,Changsha,Nanjing and Hangzhou are gradual-hard elastic systems.Finally using the nonlinear dynamical equations,the series of the annual precipitation climate oscillation at 17 stations in China are simulated.