巽他海峡的水交换过程研究

巽他海峡是爪哇海与东印度洋进行水交换的重要西部通道,其水交换过程与两侧水团性质和环流有密切关系。本研究基于巽他海峡及其附近海域的观测和遥感再分析数据,分析了爪哇海与印度洋通过巽他海峡进行水交换的多时间尺度变化规律,并探讨了局地和大尺度过程对水体输运的影响。研究表明,巽他海峡贯穿流主要由流出爪哇海的年均南向流与随季风南北转向的季节反向流组成,并存在显著的季节内变化。2008—2016年期间,巽他海峡贯穿流3次观测的年均流量分别为(-0.31±0.34),(-0.27±0.43)和(-0.49±0.31)Sv(负号代表流出爪哇海)。巽他海峡贯穿流与局地风和海峡两侧海表面高度梯度密切相关,因此采用多元回归重构了1993—2017年水体输运时间序列,并计算出25 a的平均流量为(-0.37±0.43)Sv。研究也表明,巽他海峡水体输运的年际变化异常与ENSO,IOD相关。

Study on the Water Exchange in the Sunda Strait

The Sunda Strait is an important passageway for water exchange between the Java Sea and the eastern Indian Ocean.Its water exchange process is closely related to the characteristics of water masses and circulation of its two sides.Basing on observation and remote sensing data in the Sunda Strait and its adjacent waters,this paper analyses the multi-time-scale variation of water exchange between the Java Sea and the Indian Ocean through the Sunda Strait,and explores the effects of local and large-scale processes on the water transport.Observations show that the Sunda Strait throughflow is mainly composed of the annual mean southward current flowing out of the Java Sea and the seasonally reversal current driven by monsoon with significant intraseasonal variability.From 2008 to 2016,the average annual water transport through the Sunda Strait based on three observations was(-0.31±0.34),(-0.27±0.43)and(-0.49±0.31)Sv(The minus sign represents the outflow of the Java Sea),respectively.The Sunda Strait throughflow is closely related to the local zonal wind and the sea surface height gradient on both sides of the strait.The time series of water transport reconstructed by multivariate regression from 1993 to 2017 can be used to calculate the average discharge for 25 years,which is(-0.37±0.43)Sv.The study also shows that the abnormal water transport in the Sunda Strait is closely related to ENSO and Indian Ocean Dipole.