热带印度洋海平面低频变化及机理研究

发布时间：2018-07-15 07:06

【摘要】：本文采用卫星高度计数据、验潮站数据以及海平面重构数据较为系统的分析了热带印度洋海平面低频变化特征；结合温盐、流场和风场与海平面变化的关系，探讨海平面年际变化机理。热带印度洋海平面年际变化具有显著的区域性特征，主要集中在西南热带印度洋和苏门答腊-爪哇岛沿岸，标准差可达8cm。西南热带印度洋海平面变化滞后苏门答腊-爪哇海区3个月时，相关系数达到最大负值-0.88，印度半岛沿岸和澳大利亚西部沿岸的验潮站海平面变化序列有很好的滞后关系。IOD（印度洋偶极子）和ENSO事件共同发生期间海平面变化较IOD事件期间更为显著，IOD事件期间的海平面变化较ENSO事件期间强且范围广，ENSO事件期间的海平面变化则主要位于南热带印度洋。澳大利亚西岸海平面卫星高度计数据、以及Fremantle验潮站均与ENSO指数有很好相关关系，同步相关系数超过-0.6。海平面EOF第1模态的方差贡献为44%，呈东西反向变化，第2模态则主要表现为“三明治”结构。热带印度洋海平面存在年代际变化，主要集中在年际变化显著的海域（西南热带印度洋和苏门答腊-爪哇海区）。海平面年代际变化具有显著的空间差异，重构数据显示年代际变化空间分布与年际变化相似，且与太平洋年代际振荡（PDO）有关。52年的重构数据第1模态的方差贡献为73%，与PDO指数呈负相关，分别在1974和1994年达到年代际的极值；澳大利亚西岸验潮站海平面序列也与PDO密切相关，两者的相关系数达到-0.75。区域海平面年际变化的主要影响因素是比容效应和大气风场强迫，而海洋环流与净热通量在局部区域也有着重要作用。大气风场通过Ekman效应和斜压Rossby波影响海平面变化，且区域特征显著。洋盆尺度上，斜压Rossby的作用明显大于局地Ekman效应，前者能解释30%的海平面年际变化；仅在阿拉伯海和南热带印度洋中部，风场强迫的局地Ekman效应对海平面年际变化的影响更为显著。IOD和ENSO事件期间的风场与海平面年际变化有重要联系，使得ENSO事件期间的海平面年际变化偏南偏弱。洋盆尺度上，比容效应能解释至少50%的海平面变化。主温跃层的抬升（下沉）伴随海水的增温（降温），相应出现海平面的抬升（下沉），海水温度的垂直结构变化与海平面年际变化有很好的一致性。热带印度洋大部分海域海表净热通量引起的海平面变化与实测海平面变化呈负相关，而在阿拉伯海域热通量有重要作用。合成分析显示，，在西南热带印度洋出现逆时针流涡，与顺时针的背景流场相反，IOD+ENSO事件期间最强，IOD事件期间次之，ENSO事件期间最弱；逆时针流场的存在使得在三种事件期间将会在西南热带印度洋产生海平面正异常，流场的输运对海平面变化有调整作用。印尼贯穿流与澳大利亚西岸海平面变化有密切关系。
[Abstract]:By using satellite altimeter data, tidal station data and sea-level reconstruction data, the characteristics of low frequency variation in the tropical India ocean are systematically analyzed, and the interannual variation mechanism of sea level is discussed with the relation of temperature and salt, flow field and wind field to sea level change.
The interannual variation of the sea level in the tropical India ocean has significant regional characteristics, mainly in the coastal areas of the southwest tropical India ocean and Sumatra Java. The standard deviation can reach the Sumatra Java Sea area of the southwestern tropical India ocean and the 3 months in the Sumatra Java Sea area. The correlation coefficient reaches the maximum negative value -0.88, India Peninsula coast and Australia Dali. The sea level variation sequence of the tidal station on the coast of the Western Asia has a good lag relation.IOD (India Ocean dipole) and the ENSO event, the sea level changes are more significant than that of the IOD event, and the sea level changes during the IOD event are stronger and wider than the ENSO events, and the sea level changes during the ENSO event are mainly in the South tropics. The India ocean. The sea level altimeter data of the western coast of Australia and the Fremantle tide gauge have a good correlation with the ENSO index. The variance contribution of the synchronous correlation coefficient over the EOF first mode of the -0.6. sea level is 44%, and the second mode is mainly a "sandwich" structure.
The interdecadal change of sea level in the tropical India ocean is mainly concentrated in the sea area with significant interannual variation (the India ocean and Sumatra Java Sea area in the southwest tropical region). The interdecadal variations of the sea level have significant spatial differences. The reconstructive data show that the interdecadal spatial distribution of the interdecadal variation is similar to that of the interdecadal changes in the Pacific Ocean (PDO). The variance contribution of the first mode of reconstructing data in.52 is 73%, which is negatively correlated with the PDO index, reaching the interdecadal extreme value in 1974 and 1994, respectively. The sea level sequence of the West Bank test station in Australia is also closely related to PDO, and the correlation coefficient reaches -0.75..
The main influencing factors of regional sea level interannual change are specific volume effect and atmospheric wind force, and ocean circulation and net heat flux also play an important role in local area. The atmospheric wind field affects sea level through Ekman effect and baroclinic Rossby wave, and the regional characteristics are significant. The role of baroclinic Rossby is obviously greater than local E on the scale of the ocean basin. The kman effect, the former can explain the interannual variation of 30% sea level; only in the Arabia sea and the middle of the India ocean in the southern tropics, the influence of the local Ekman effect on the interannual variation of the sea level is more significant in the period of.IOD and ENSO events and the interannual variation of the sea level during the period of the event, which makes the interannual variation of sea level during the ENSO event. On the scale of the ocean, the specific volume effect can explain at least 50% of the sea level change. The uplift (subsidence) of the main thermocline is accompanied by the temperature increase (cooling) and the elevation of the sea level (subsidence). The vertical structure change of the sea water temperature is in good agreement with the interannual variation of sea level. The sea surface net heat of most of the tropical India ocean is in the sea surface. The sea level change caused by flux has a negative correlation with the measured sea level changes, and the heat flux in the Arabia sea area has an important role. The synthetic analysis shows that the reverse clockwise flow of the India ocean in the southwest tropical region is the strongest, the IOD+ENSO event is the strongest, the ENSO event is the weakest, and the counterclockwise flow is the reverse clockwise flow. The existence of the field leads to a positive sea level anomaly in the southwest tropical India ocean during the three events. The transport of the flow field has an adjustment effect on the sea level change. The Indonesian penetration flow is closely related to the sea level change in the West Bank of Australia.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.23

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