江苏海陆局地气候要素分数维对比研究

A Fractal Dimension Comparison of Local Climate Elements of Jiangsu Inland and Offshore Areas

将分数维分析方法应用于江苏海洋和内陆的局地温度、气压的气候要素时间演变的对比与分析。通过对盒维数法的变通改进,计算和对比江苏内陆和江苏北部海区近20 a年平均及月平均温压气候要素时间序列的分数维,定量化地指示要素系统及演变的复杂性。在此基础上,设计计算了分数维双向累积频率分布,从分数维频率分布图中提取系统年代际尺度的主要气候特征。依据频率分布的偏态结构,客观选择典型年份,并以流场为例分析系统年代际的典型平均空间背景场结构,得到在这两个年代中,前10 a北方大陆气团较强,流场动力性较强,而后9 a南方热带气团向北移动,流场动力性减弱。总之分数维参数定量化方法能够较确切地描述最近20 a江苏局地海陆气候要素演变特征。

To analyze and compare the temporal evolution characters of the climate elements（tempera-ture and pressure） of Jiangsu inland and offshore areas, an improved box-counting method was used to calculate the fractal dimension of the yearly and monthly element series of three representative stations in the period 1988-2006;and the fractal dimension was used to quantitatively describe the complexity of the evolution of the element systems. Furthermore, a two-side cumulative frequency distribution for the fractal dimension was designed and calculated, and the major climate characters of the evolution systems on the interdecadal scale were extracted from the calculated distributions. According to the bias structure of the cumulative frequency distribution, the typical years for the first l0 years and later 9 years were objectively determined. It has also been found from the typical spatial background fields that in the first decade the northern continental air mass controlled the streamline fields over Jiangsu province with strong momentum ;while in the later decade, the wind streamline field was weaker due to the influence of the northward-moved tropical air mass. In short, the fractal dimension method is able to better describe the evolution character of climate element systems of local land and sea areas in Jiangsu in the past 20 years.