摘要
本文分析了太平洋236个水位站的月平均序列,对其中大于45a的序列进行二阶谱和二阶凝聚谱分析,表明这些序列中有的周期成分相位相关性显著.因此采用考虑非线性效应的混合谱分析方法,重复进行谱分析及周期检验和最小二乘滤波、逐次检验并滤掉最显著的周期分量,求得序列中的显著周期.结果表明水位序列的振动周期因站而异,并非固定不变.讨论了准2a大气振动周期、与厄尔尼诺(EI Ni(?)o)事件相关的3～7a周期、太阳黑子、双太阳黑子和25～30a超长振动周期的存在.用显著周期分量加线性趋势项拟合月平均水位序列,结果中国沿海年周期迟角南北分布趋势与太平洋大部分海区的分布趋势几乎相反.在EI Ni(?)o事件影响较大的低纬区,2～7a内各种周期振幅之和与年振幅之比量值>1.0,周期大于8a的振幅之和与年振幅之比量值>0.5,这表明该区月平均水位序列中年振动的主导作用下降,与此对应存在显著的EI Ni(?)o事件周期成分,及准10a和10a以上的长周期振动.若不计海平面异常升降值,太平洋相对海平面平均上升率为1.16mm/a.按线性趋势项的正负及海区的地理位置,对东南亚包括中国沿海在内的太平洋海平面的升降进行了区划,分析了各海区海平面的升降趋势,由于各种因素的影响其结果变化较大.
The monthly mean series of 236 sea level(SL)stations in the Pacific Ocean are analysed. The outcome of bispectrum and bicoherence analysis applied to the data of the stations with a record of more than 45 years suggest that phase coherences between pairs of period compo-nents are significant among some of these series. Thus mixed spectra modeled by a nonlinear system are adopted, through which spectral analysis, test of the significant period and least square filtering are conducted repeatedly, so the most significant perion components are tested and filteredoff step by step to get the significant periods of the series. The results indicate that the oscillation periods of SL series are variable with different stations. The existence of quasi-2 year period of atmosphere oscillation, 3-7 year period linked with El-Nino event, the sunspot and bisunspot periods, and extra-long period of 25-30 year oscillation are approached.The SL series of monthly mean are fitted by the obtained significant period components plus linear trend. The outcome is that the distributional pattern of annual periodic phase lag from the south to the north of China seas is almost opposite to that over most parts of the Pacific Ocean. To the lower latitudes where the effect of El-Nino is apparent, the ratio of the sum of the amplitudes corresponding to various periods for 2-7 years and the annual amplitude is equal to or greater than 1. 0,and the ratio of the sum of the amplitudes corresponding to the periods over 8 years and the annual amplitude is equal to or greater than 0. 5, which leads to the conclusion that the annual oscillation in monthly mean value of SL becomes less dominant in these areas while there exist the significant periodic components of El-Nino and long period oscillation of quasidecade and more than a decade.The average rising rate of relative SL of the Pacific Ocean is 1. 16mm/a if anomalous rising and falling rates are not counted. In terms of the positives and negatives of linear trends and the geographic positions of ea
出处
《海洋通报》
CAS
CSCD
北大核心
1994年第6期1-16,共16页
Marine Science Bulletin
基金
国家自然科学基金(49376261)
国家科委项目(K90-05-20-03)
(C85-03-02)资助
关键词
太平洋
水位
周期变化
非线性
升降趋势
Pacific Ocean
sea level
monthly mean
rising trend
nonlinear
bispectrum
spectral analysis
periodic analysis
