南海海表盐度的分布特征

发布时间：2018-10-05 18:11

【摘要】：海表盐度（SSS）作为描述海洋基本性质的关键变量之一，对其分布和变化规律的研究有助于了解海洋环流、海洋碳循环、全球水循环以及海洋大气之间的相互作用对全球气候的影响。随着SSS的重要性与日俱增，及其测量方法的不断完善，国内外对于SSS的研究不仅表现在SSS的分布特征和影响因素的研究，以及SSS对全球水循环和大洋环流等气候特征的影响方面的研究，还包括SSS反演算法和精确地的提高和校正方面。总结国内外SSS研究进展的基础上发现，南海特殊的地理位置与气候特征决定了南海SSS对南海环流以及海气之间的相互作用具有重要的影响，并且由于受到南海海域的观测数据在区域上不完整或者时间上不连续的影响，近几年来对南海SSS的研究重点在卫星遥感数据的精度校准上。因此，对南海SSS的分布特征进行分析，有益于了解南海环流和水循环对气候的影响，同时，可以为下一步卫星海表盐度反演精度的提高提供数据和观测基础。基于此，本文利用1980年-2011年长达32年的SODA月平均海表盐度和2011年的高分辨率的HYCOM/NCODA日平均再分析资料，，重点讨论了南海海表盐度SSS的分布特征和差异分析，重点讨论了南海海表盐度SSS的分布特征和差异分析。主要的研究内容如下：（1）利用最小二乘法对南海的SODA月平均海表盐度数据进行线性拟合分析SSS异常的变化趋势。结果显示，从1980年到2011年，南海SSS总体上呈现出下降的趋势。（2）利用EOF分析方法对南海的SODA月平均海表盐度数据进行时空分解。结果显示，第1模态EOF分析表明南海SSS具有同相位的变化；第2、3模态EOF分析说明不同海域的SSS异常变化是有差别的，其中，在南海北部和南部SSS异常变化大且呈反相关，在南海中部SSS异常变化小。（3）主要通过处理分析2011年的高分辨率的HYCOM/NCODA日平均盐度资料，并将之与同年的SODA月平均海洋同化数据盐度资料进行对比，分析两者之间的差异，以及在南海的SSS的分布特征。处理结果表明，2011年的南海月平均SSS在时间上都是先升高后降低再升高的趋势。通过对比这两种数据的SSS偏差，发现各自都随各自的月平均盐度而上下起伏，但是前者的变化在时间上更规律一些，后者则是在区域上有较大的浮动。两者相减得到的SSS差异在南海不同的海域上表现不一样，基本上跟SSS的季节变化有关。通过使用最小二乘法对HYCOM/NCODA SSS数据和SODA SSS数据进行线性拟合和计算RMSE发现，它们之间存在正相关，虽然相关性不是非常显著，但是在一定程度上仍能说明这两种数据在表现南海SSS的分布特征上是基本一致的。另外在本文的最后，对于南海SSS的小尺度分布特征进行了初步分析，结果显示，选择的样本点内的SSS基本上可以代表1°ｘ1°范围内的SSS，相对来说几个异常值的存在对于进行卫星海表盐度的反演精度提高的研究来说是有意义的。
[Abstract]:Sea surface salinity (SSS) is one of the key variables to describe the basic properties of the ocean. The study of its distribution and variation is helpful to understand the ocean circulation and the ocean carbon cycle. The effects of the global water cycle and the interactions between the oceans and the atmosphere on the global climate. With the increasing importance of SSS and the continuous improvement of measurement methods, the research of SSS at home and abroad is not only reflected in the distribution characteristics of SSS and the study of influencing factors. The effects of SSS on the global water cycle and oceanic circulation, including the SSS inversion algorithm and the precise improvement and correction of the SSS inversion algorithm, are also discussed. On the basis of summarizing the research progress of SSS at home and abroad, it is found that the special geographical location and climatic characteristics of the South China Sea determine that the South China Sea SSS plays an important role in the South China Sea circulation and the interaction between sea and atmosphere. Due to the incomplete or temporal discontinuity of the observed data in the South China Sea, the research on the SSS in the South China Sea has focused on the accuracy calibration of the satellite remote sensing data in recent years. Therefore, the analysis of the distribution characteristics of SSS in the South China Sea is helpful to understand the influence of the circulation and water cycle in the South China Sea on the climate, at the same time, it can provide the data and observation basis for improving the accuracy of the inversion of sea surface salinity of the satellite in the next step. Based on this, the distribution characteristics and difference analysis of SODA monthly mean sea surface salinity from 1980 to 2011 and high-resolution daily average HYCOM/NCODA reanalysis data from 2011 are used to discuss the distribution characteristics and difference analysis of SSS in the South China Sea. The distribution characteristics and difference analysis of sea surface salinity (SSS) in the South China Sea are discussed in detail. The main research contents are as follows: (1) the variation trend of SSS anomaly is analyzed by linear fitting of SODA monthly mean sea surface salinity data in the South China Sea by least square method. The results show that from 1980 to 2011, the South China Sea SSS generally showed a downward trend. (2) the SODA monthly mean sea surface salinity data of the South China Sea are decomposed by EOF method. The results show that the first mode EOF analysis shows that the SSS in the South China Sea has the same phase change, the second mode EOF analysis shows that there are differences in the variation of SSS anomaly in different sea areas, among which, the SSS anomaly in the north and south of the South China Sea varies greatly and is inversely correlated. In the middle of the South China Sea, the SSS anomaly change is small. (3) by processing and analyzing the high-resolution HYCOM/NCODA daily average salinity data in 2011 and comparing it with the SODA monthly average ocean assimilation data of the same year, the differences between the two data and the distribution characteristics of SSS in the South China Sea are analyzed. The results show that the average monthly SSS of the South China Sea in 2011 increased first and then decreased and then increased. By comparing the SSS deviations of the two data, it is found that each of them fluctuates with their monthly average salinity, but the former is more regular in time, and the latter is larger in region. The difference of SSS between them is different in different waters of the South China Sea, which is related to the seasonal variation of SSS. By linear fitting and calculating RMSE of HYCOM/NCODA SSS data and SODA SSS data using the least square method, it is found that there is a positive correlation between them, although the correlation is not very significant. To some extent, however, these two kinds of data are consistent in the distribution of SSS in the South China Sea. In addition, at the end of this paper, the small scale distribution characteristics of SSS in the South China Sea are analyzed, and the results show that, The SSS in the selected sample points can basically represent the existence of several outliers in the range of 1 掳x 1 掳for the study of improving the accuracy of the inversion of sea surface salinity.
【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】：P731.12

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