登陆中国热带风暴年际和年代际变化及其与全球大尺度环流的相关

Principal Time Modes of the Interannual and Decadal Variations of Landfall Tropical Storm Number in China and Their Relationships to the Global Large Scale Circulation

利用集合经验模态分解(EEMD)方法研究了登陆中国热带风暴频数的非平稳年际和年代际变化主要周期型。对1951—2006年登陆中国的热带风暴频数序列进行分解,分别得到包含有准4年(C01)、6～7年(C02)的年际周期分量和14～16年(C03)的年代际周期分量的时间变化型。这些分量给出了登陆中国热带风暴频数在不同时间尺度上独立的变化特征,其中C01周期分量强度最大,且与ENSO有关。登陆中国的热带风暴频数趋势分量不显著,表明近56年来登陆中国热带风暴无明显增加(减少)趋势。这些周期分量与夏季海平面气压场的相关分析表明,登陆中国热带风暴频数年代际变化与南半球热带和中高纬度环流系统的相互作用密切相关。

Ensemble empirical mode decomposition（EEMD） method was adopted to study the non-stationary interannual and decadal variations of landfall tropical storm number in China.Time series of the landfall tropical storm number of 56 years（1951-2006） can be decomposed into a series of modes,mainly including the quasi 4 years（C01）,6-7 years（C02） and 14-16 years（C03） oscillation components.Among them,the quasi 4-year oscillation with the largest amplitude is related to ENSO.In brief,the EEMD method instead of traditional and conventional decomposition methods can bring us the isolated characteristics of the temporal variations of the landfall tropical storm number on various time scales,especially on the interannual and decadal timescales.In addition,the long-range trend is not obvious,indicating that there was no increasing or declining trend in the series of landfall tropical storm number in the past 56 years.Moreover,the correlation analysis also suggests that the interdecadal variations of landfall tropical storm number in China were closely related to the interaction between tropical and extratropical circulation systems in the Southern Hemisphere.