熱帶太平洋海溫變率模態(tài)的結(jié)構(gòu)特征分析
發(fā)布時間：2019-04-08 10:50
【摘要】：本文針對去趨勢的Hadley中心1958-2008年月平均海溫數(shù)據(jù),采用季節(jié)聯(lián)合正交經(jīng)驗分解(SEOF)的分析方法,揭示了熱帶太平洋海溫異常變率的兩個主要季節(jié)演變模態(tài)。SEOF-1為年際變率模態(tài),主周期為3年和5年,反映了傳統(tǒng)的ENSO模態(tài),與全球海洋、表現(xiàn)熱通量、大氣環(huán)流及降水異常都具有明顯的遙相關(guān),全球性影響顯著。SEOF-2為年代際變率模態(tài),主周期為10-12年,包含有赤道中太平洋和副熱帶東北太平洋兩個不同步的暖異常中心、以及東太平洋的冷異常中心。該年代際變率模態(tài)的全球遙相關(guān)分布具有明顯的局地性特征,主要集中于熱帶及北太平洋區(qū)域。本文較為細致地分析了模態(tài)的結(jié)構(gòu)特征及各部分之間的關(guān)系。研究發(fā)現(xiàn)：副熱帶東北太平洋暖異常中心海溫距平計算的指數(shù)、及由赤道緯向反位相的冷暖異常差值計算的指數(shù)都與SEOF-2模態(tài)時間序列的相關(guān)性較高,同時與ENSO相對獨立,但兩指數(shù)之間相關(guān)性非常弱,具有一定的獨立性；兩個指數(shù)都具有一定的穩(wěn)定性,即ENSO信號存在與否不影響指數(shù)本身的變化規(guī)律,也不影響兩指數(shù)之間及與SEOF-2時間序列的相關(guān)關(guān)系；另外,兩個指數(shù)各自能夠單獨回歸出SEOF-2模態(tài)中的一部分海溫異常形態(tài),副熱帶東北太平洋海溫異常指數(shù)能回歸得到該模態(tài)中大部分的暖異常,尤其是赤道中太平洋及副熱帶東北太平洋的兩個暖中心十分明顯,赤道緯向反位相結(jié)構(gòu)海溫異常指數(shù)則能回歸得到該模態(tài)中赤道緯向反位相變化部分,尤其是東太平洋冷異常明顯,而且兩指數(shù)回歸的海溫異常的合成與原模態(tài)十分相近,說明該模態(tài)很有可能是兩種具有不同性質(zhì)的海溫異常模態(tài)的合成或者伴隨發(fā)生的結(jié)果,暗示了該模態(tài)具有被再分解的可能性。利于傅利葉濾波方法從原始海溫異常中濾掉了8年以下的高頻振蕩,對剩余的以年代際低頻變率為主的熱帶太平洋海溫異常再次進行SEOF分解,得到兩個具有不同特性的年代際變率模態(tài)。第一模態(tài)主周期12-15年,表現(xiàn)為中東太平洋赤道及兩側(cè)的三角形區(qū)域內(nèi)同時增暖,位于赤道中太平洋及副熱帶東北太平洋位置各有一個暖異常中心,由于該模態(tài)呈現(xiàn)出經(jīng)向的雙暖中心結(jié)構(gòu),定義此模態(tài)為熱帶太平洋年代際變率經(jīng)向模態(tài)(Tropical Pacific interdecadal meridional mode, TPDMM),此模態(tài)與副熱帶東北太平洋海溫指數(shù)在時間變化及海溫異常形態(tài)分布上都十分相似;第二模態(tài)最突出的周期為20年左右,表示為赤道東太平洋為較強的冷異常,中太平洋為相對較弱的暖異常,該模態(tài)表現(xiàn)為赤道緯向的冷暖異常反位相結(jié)構(gòu),故定義此模態(tài)為熱帶太平洋年代際變率緯向模態(tài)(Tropical Pacific interdecadal zonal mode, TPDZM),同樣,此模態(tài)與赤道緯向反位相結(jié)構(gòu)海溫指數(shù)回歸的海溫模態(tài)及時間序列對應(yīng)關(guān)系也非常良好。進一步的研究發(fā)現(xiàn)這兩個再分解得到的年代際模態(tài)都具有現(xiàn)實的意義,TPDMM模態(tài)的全球遙相關(guān)分布呈現(xiàn)出“類ENSO (ENSO-like)"形態(tài),而且與ENSO的時間序列也具有協(xié)同變化的特點,暗示TPDMM可能是ENSO在年代際之間的調(diào)整產(chǎn)生的結(jié)果；TPDZM則反映了熱帶太平洋海溫平均態(tài)的變化。
[Abstract]:In this paper, the two main seasonal evolution modes of the sea surface temperature anomaly rate in the tropical Pacific are revealed by the analysis method of the seasonal joint orthogonal empirical decomposition (SEOF) for the average sea temperature data of the Hadley center, which is going to the trend, from 1958 to 2008. SEOF-1 is the interannual variability mode, the main period is 3 years and 5 years, the traditional ENSO mode is reflected, and the global ocean, the performance heat flux, the atmospheric circulation and the precipitation anomaly have obvious remote correlation, and the global influence is remarkable. SEOF-2 is an interdecadal variability mode with a main cycle of 10-12 years, including two non-synchronized warm anomaly centers in the Pacific and subtropical North-East Pacific in the equator, and a cold anomaly center in the Eastern Pacific. The global teleconnection distribution of interdecadal variability mode has obvious local characteristics, mainly in the tropical and northern Pacific region. In this paper, the structural characteristics of the modal and the relation between the parts are analyzed in detail. It is found that the index of the SST anomaly in the warm anomaly center in the North-East Pacific Ocean and the index of the cold and warm anomaly of the equatorial zonal inversion phase are higher than that of the SEOF-2 mode time series, while the correlation with the ENSO is very weak, but the correlation between the two indices is very weak, The two indexes have certain stability, that is, the presence or absence of the ENSO signal does not affect the change law of the index itself, nor does it affect the correlation between the two indexes and the SEOF-2 time series; in addition, the two indexes can be respectively returned to a part of the sea surface temperature anomaly in the SEOF-2 mode, and the SST anomaly index in the northeast Pacific of the subtropical zone can be returned to obtain most of the warm anomalies in the mode, especially the two warm centers of the Pacific and the subtropic Pacific in the equator are very obvious, The temperature anomaly index of the equatorial zonal reverse-phase structure can be regressed to obtain the variation of the equatorial latitudinal inversion in this mode, especially the cold anomaly of the eastern Pacific, and the anomaly of the sea surface temperature of the two-index regression is very similar to that of the original mode. It is suggested that the mode is likely to be the combination of two sea surface temperature anomaly modes with different properties or the result of the occurrence, which implies that the mode has the possibility of re-decomposition. The method is beneficial to the Fourier-leaf filtering method to filter out the high-frequency oscillation below 8 years from the original sea temperature anomaly, and again carry out SEOF decomposition on the rest of the tropical Pacific sea surface temperature anomaly, which is dominated by the inter-time low-frequency variability, to obtain two interdecadal variability modes with different characteristics. the main period of the first mode is 12-15 years, and the main period of the first mode is 12-15 years, This mode is defined as the meridional mode (TPDMM) of the interdecadal variability of the tropical Pacific. This mode is very similar to that of the Pacific SST in the north-east of the subtropical zone. The most prominent period of the second mode is about 20 years. It is indicated that the equatorial eastern Pacific is a relatively weak cold anomaly, and the middle and the Pacific are relatively weak warm and abnormal, the mode is the equatorial zonal cold and warm abnormal reverse phase structure, so this mode is defined as the tropic Pacific interdecadal zontal mode (TPDZM) in the tropical Pacific. The relationship between the modal and the time series of the sea surface temperature index regression with the equatorial zonal inversion is also very good. The further study found that the interdecadal mode of the two re-decomposition has the real meaning, and the global teleconnection distribution of the TPDMM mode presents the "ENSO-like" form, and the time series with the ENSO also has the characteristic of cooperative change, It is suggested that the TPDMM may be the result of the adjustment of the ENSO between the ages, and the TPDZM reflects the change of the mean state of the sea surface temperature in the tropical Pacific.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：P731.11
本文編號：2454516
[Abstract]:In this paper, the two main seasonal evolution modes of the sea surface temperature anomaly rate in the tropical Pacific are revealed by the analysis method of the seasonal joint orthogonal empirical decomposition (SEOF) for the average sea temperature data of the Hadley center, which is going to the trend, from 1958 to 2008. SEOF-1 is the interannual variability mode, the main period is 3 years and 5 years, the traditional ENSO mode is reflected, and the global ocean, the performance heat flux, the atmospheric circulation and the precipitation anomaly have obvious remote correlation, and the global influence is remarkable. SEOF-2 is an interdecadal variability mode with a main cycle of 10-12 years, including two non-synchronized warm anomaly centers in the Pacific and subtropical North-East Pacific in the equator, and a cold anomaly center in the Eastern Pacific. The global teleconnection distribution of interdecadal variability mode has obvious local characteristics, mainly in the tropical and northern Pacific region. In this paper, the structural characteristics of the modal and the relation between the parts are analyzed in detail. It is found that the index of the SST anomaly in the warm anomaly center in the North-East Pacific Ocean and the index of the cold and warm anomaly of the equatorial zonal inversion phase are higher than that of the SEOF-2 mode time series, while the correlation with the ENSO is very weak, but the correlation between the two indices is very weak, The two indexes have certain stability, that is, the presence or absence of the ENSO signal does not affect the change law of the index itself, nor does it affect the correlation between the two indexes and the SEOF-2 time series; in addition, the two indexes can be respectively returned to a part of the sea surface temperature anomaly in the SEOF-2 mode, and the SST anomaly index in the northeast Pacific of the subtropical zone can be returned to obtain most of the warm anomalies in the mode, especially the two warm centers of the Pacific and the subtropic Pacific in the equator are very obvious, The temperature anomaly index of the equatorial zonal reverse-phase structure can be regressed to obtain the variation of the equatorial latitudinal inversion in this mode, especially the cold anomaly of the eastern Pacific, and the anomaly of the sea surface temperature of the two-index regression is very similar to that of the original mode. It is suggested that the mode is likely to be the combination of two sea surface temperature anomaly modes with different properties or the result of the occurrence, which implies that the mode has the possibility of re-decomposition. The method is beneficial to the Fourier-leaf filtering method to filter out the high-frequency oscillation below 8 years from the original sea temperature anomaly, and again carry out SEOF decomposition on the rest of the tropical Pacific sea surface temperature anomaly, which is dominated by the inter-time low-frequency variability, to obtain two interdecadal variability modes with different characteristics. the main period of the first mode is 12-15 years, and the main period of the first mode is 12-15 years, This mode is defined as the meridional mode (TPDMM) of the interdecadal variability of the tropical Pacific. This mode is very similar to that of the Pacific SST in the north-east of the subtropical zone. The most prominent period of the second mode is about 20 years. It is indicated that the equatorial eastern Pacific is a relatively weak cold anomaly, and the middle and the Pacific are relatively weak warm and abnormal, the mode is the equatorial zonal cold and warm abnormal reverse phase structure, so this mode is defined as the tropic Pacific interdecadal zontal mode (TPDZM) in the tropical Pacific. The relationship between the modal and the time series of the sea surface temperature index regression with the equatorial zonal inversion is also very good. The further study found that the interdecadal mode of the two re-decomposition has the real meaning, and the global teleconnection distribution of the TPDMM mode presents the "ENSO-like" form, and the time series with the ENSO also has the characteristic of cooperative change, It is suggested that the TPDMM may be the result of the adjustment of the ENSO between the ages, and the TPDZM reflects the change of the mean state of the sea surface temperature in the tropical Pacific.
【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：P731.11
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