苏拉威西海海面高度多频率季节内变化及其机制分析

Multi-frequency variability and mechanism of intra-seasonal sea surface height in the Sulawesi Sea

本文利用1993-2022年卫星高度计观测数据,分析苏拉威西海海面高度多频率季节内变化信号的时空特征,利用罗斯贝标准模理论给出动力解释。谱分析显示,苏拉威西海海面高度变化存在很强的30~90 d的季节内信号,其平均功率谱密度为半年内信号平均功率谱密度的13倍。这些季节内信号具有离散、不连续的谱峰周期,其中54.0 d和64.4 d的峰值最大,分别为30~90 d信号平均谱值的28倍和23倍。罗斯贝标准模态理论分析显示,近封闭的苏拉威西深海盆存在离散的罗斯贝标准模态。卫星高度计观测的季节内变化与罗斯贝标准模态结果的二维空间结构演化、周期以及西传速度一致,罗斯贝标准模态解的叠加呈现出与海面高度变化相似的方差分布,这说明苏拉威西海海盆的固有振荡是其季节内变化特征形成的重要机制之一。

Based on the satellite altimeter observation data from 1993 to 2022,this paper analyzes the temporal and spatial characteristics of the multi frequency seasonal variation signal of sea surface height in the Sulawesi sea,and gives the dynamic interpretation by using Rossby standard mode theory.The spectral analysis shows that there is a strong intra-seasonal signal of 30-90 days in the sea surface height variation of Sulawesi sea,and its average power spectral density is 13 times of the average power spectral density of the signal in half a year.These seasonal signals have discrete and discontinuous spectral peak periods,and the peaks of 54.0 d and 64.4 d are the largest,which are 28 times and 23 times of the signal of 30-90 days,respectively.The theoretical analysis shows that the existence of Rossby standard modes in the nearly closed Sulawesi deep-sea basin.The seasonal variation observed by satellite altimeter is consistent with the two-dimensional spatial structure evolution,period and westward propagation velocity of Rossby standard mode results,the superposition of Rossby standard mode solutions presents a variance distribution similar to the sea surface height variation field.This shows that the inherent oscillation of Sulawesi Sea basin is one of the important mechanisms that contribute to its intra-seasonal variation.