基于卫星高度计数据的南海海平面时空变化特征分析

Analysis of Spatial and Temporal Variation of Sea Level in South China Sea Based on Satellite Altimeter Data

本文利用卫星高度计数据,采用多种方法对1993-2017年中国南海海平面高度异常(Sea Level Anomaly,SLA)的空间分布和时间变化进行分析,主要采取的方法有线性回归、Winters指数平滑法、经验模态分解(Empirical Modal Decomposition,EMD)和经验正交函数(Empirical Orthogonal Function,EOF)。通过研究发现,南海大部分海域的多年平均SLA为正值,只有很少一部分海域出现负值(菲律宾群岛中部海域),并且南海的平均SLA有明显的季节性变化。利用线性回归的方法,发现1993-2017年的南海海平面总体呈现上升趋势。利用EMD分析法发现南海有明显的年际和年代际变化。研究结果表明:中国南海海平面高度呈不断上升的趋势,具有明显的季节和年际变化周期,且ENSO对中国南海海平面的作用不可忽视。

Based on satellite altimeter data,the spatial distribution and temporal variation of Sea Level Anomalies(SLA)in the South China Sea(SCS)from 1993 to 2017 are analyzed by various methods.The main methods include linear regression,Winters exponential smoothing,Empirical Mode Decomposition(EMD)and Empirical Orthogonal Function(EOF).The results show that the annual mean SLA in most areas of the SCS is positive,and only a small number of areas have negative values(the central part of the Philippine Islands),and the mean SLA in the SCS have obvious seasonal changes.Using the linear regression method,it was found that the sea level of the SCS from 1993 to 2017 showed an overall upward trend.Based on EMD analysis,it was found that there are obvious “interannualand interdecadalchanges in the SCS.The conclusions show that the sea level in the SCS is rising,with obvious seasonal and interannual cycles,and the role of ENSO on the sea level in the SCS cannot be ignored.