西太平洋暖池海温准半年振荡的年际变化及其可能机制研究

发布时间：2018-06-25 01:16

  本文选题：西太平洋暖池 + 准半年振荡　； 参考：《南京信息工程大学》2016年硕士论文

【摘要】：本文采用1982-2014年逐月NOAA最优插值海表面温度资料OISST、海气界面热通量资料、OLR资料、再分析降水资料(CMAP)以及大气环流要素场资料等,并利用旋转经验正交函数分解REOF、Morlet小波分析、功率谱分析、Butterworth带通滤波等分析方法,对西太平洋暖池WPWP中的准半年振荡现象SAO及其年际变化特征进行揭示和分析,并通过海气相互作用及ENSO循环来探讨WPWP中SAO年际变化的影响要素及其形成机制,最后通过P-SAO型与N-SAO型所对应的东亚大气环流与我国东部地区降水情况来分析SAO的年际变化对东亚气候的影响。主要研究结果如下：(1)选取20°S-20°N,120°E-160°E作为WPWP的研究区域,通过REOF方法选取第一模态作为WPWP的主要空间模态,通过对第一模态的时间序列PCI进行功率谱分析和Morlet小波分析发现,WPWP海域中显著存在着5-7个月周期的振荡现象。接着对PCI进行5-7个月的带通滤波处理,可以发现该时间序列在不同年份的位相演变存在着三种不同的情况：P-SAO型、N-SAO型和中性情况,说明WPWP中的SAO现象存在着很强的年际变化,其中P-SAO型和N-SAO型以完全相反的位相发展,且均具有显著的季节依赖性。(2) WPWP海温场的SAO与海表面热量平衡之间有着密切的联系,通过净热通量NH或者通过OLR和风速这两个物理量的变化可以判断海温的异常变化。WPWP海温场SAO的年际变化与ENSO循环紧密联系,其中P-SAO型和N-SAO型分别对应ENSO循环的冷、暖事件,WPWP海温场SAO年际变化的形成原因可以解释为由ENSO事件的纬向风异常引起的,通过对流-云-太阳辐射这样一个负反馈过程而形成的。(3)夏季,P-SAO型对应着我国东部地区降水分布为“南旱北涝”型,而P-SAO型则对应着“南涝北旱”型；冬季,P-SAO型对应着我国东部大部分地区降水偏多的情况,而N-SAO型则对应降水偏少情况。WPWP中SAO的年际变化与东亚大气异常环流以及我国东部地区降水异常都存在着紧密的联系。
[Abstract]:In this paper, monthly NOAA interpolation data of sea surface temperature (OISST), air-sea interface heat flux data (OLR), precipitation data (CMAP) and atmospheric circulation factor field data are analyzed, and the REOFN Morlet wavelet analysis is performed by means of rotational empirical orthogonal function. Power spectrum analysis and Butterworth band-pass filtering are used to reveal and analyze the quasi-semi-annual oscillation in WPWP of the western Pacific Ocean and its interannual variation. The influence factors and the formation mechanism of the inter-annual variation of SAO in WPWP are discussed by air-sea interaction and ENSO cycle. Finally, the influence of inter-annual variation of SAO on the climate of East Asia is analyzed through the East Asian atmospheric circulation corresponding to P-SAO and N-SAO and the precipitation in eastern China. The main results are as follows: (1) the first mode of WPWP is chosen as the main spatial mode of WPWP by using the REOF method, and 20 掳S-20 掳NV 120 掳E-160 掳E is selected as the research area of WPWP. Based on the power spectrum analysis and Morlet wavelet analysis of the first mode of time series PCI, it is found that there is a 5-7 month period oscillation phenomenon in the WPWP sea area. Then the bandpass filter processing of PCI for 5-7 months shows that there are three different cases in the phase evolution of the time series in different years, namely: P-SAO type N-SAO type and neutral case, which indicates that the SAO phenomenon in WPWP has strong interannual variation. Among them, P-SAO and N-SAO develop in completely opposite phases, and both have significant seasonal dependence. (2) there is a close relationship between the SAO of WPWP SST field and the heat balance of the sea surface. Based on the variation of net heat flux NH or OLR and wind speed, we can judge the anomalous variation of SST. The inter-annual variation of SST field in WPWP is closely related to ENSO cycle, in which P-SAO and N-SAO correspond to the cold of ENSO cycle, respectively. The formation of the inter-annual variation of the WPWP SST field can be explained by the zonal wind anomaly of the ENSO event. It is formed by a negative feedback process of convection-cloud-solar radiation. (3) in summer, the P-SAO type corresponds to the "South drought and North waterlogging" pattern in the eastern part of China, while the P-SAO type corresponds to the "South waterlogging and North drought" type; In winter, the P-SAO type corresponds to more precipitation in most areas of eastern China, while N-SAO type corresponds to less precipitation. The inter-annual variation of SAO in WPWP is closely related to the anomalous atmospheric circulation in East Asia and the precipitation anomaly in the eastern part of China.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732
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本文编号：2063845