日长变化、大气角动量和ENSO年际信号的相关分析及2020―2021年拉尼娜事件  

Correlation Analyses amongΔLOD,AAM and ENSO,and the 2020―2021 La Nina Event

作　　者：孔昭洋 周永宏[1,2,3] 许雪晴 安显然[1,4] KONG Zhao-yang;ZHOU Yong-hong;XU Xue-qing;AN Xian-ran(Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Planetary Sciences,Chinese Academy of Sciences,Shanghai 200030,China;Shanghai Key Laboratory of Space Navigation and Positioning Techniques,Shanghai 200030,China)

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院大学,北京100049 [3]中国科学院行星科学重点实验室,上海200030 [4]上海市空间导航与定位技术重点实验室,上海200030

出　　处：《天文学进展》2021年第4期532-543,共12页Progress In Astronomy

基　　金：国家自然科学基金项目(11673049,11773057);中国科学院青年创新促进会项目(2019265)。

摘　　要：作为年际尺度最强的气候变率,厄尔尼诺-南方涛动(ENSO)的发生对全球天气-气候有显著的影响,同时也与地球自转变化和大气角动量(AAM)的年际信号密切相关。基于1962年1月―2021年1月美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)的再分析资料集(R1),进行大气角动量函数计算,并将其与同时段年际分量的日长变化(ΔLOD)数据以及表征ENSO的海洋尼诺指数(ONI)和南方涛动指数(SOI)资料相对比:通过互相关分析和小波变换等统计方法分析了ENSO,AAM,ΔLOD的关联性,并给出相应过程的物理解释。同时,应用这些关联性和可能的物理过程,在日长变化的年际分量上检测到正在发生的2020―2021年中等强度拉尼娜事件信号,且在此期间年际ΔLOD已经产生约―0.18 ms的变化。As the strongest climate variability at the interannual scale,the El Nino-Southern Oscillation(ENSO)has significant impacts on global weather and climate change.And it is also closely related with the component of the interannual atmospheric angular momentum(AAM)and variation of length of day(ΔLOD).This paper calculates the excitation function of AAM,based on the dataset of National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis-1(NCEP/NCAR R1)from January 1962 to January 2021,and compares the AAM withΔLOD and the ENSO indices.The relations among the ENSO,AAM andΔLOD are analyzed by statistical methods of cross-correlation and wavelet transform analyses.And the physical explanations of corresponding processes are discussed.The results show that theΔLOD,AAM and ENSO are significantly related at the 99%level on the interannual time scale,and they have similar time-frequency wavelet spectra.The occurrences of ENSO events cause anomalies of atmospheric circulations,especially in the tropics and subtropics,which lead to variations in the AAM and LOD accordingly.Furthermore,the signal of a medium intensity La Nina event in 2020-2021 on the interannual component ofΔLOD is detected,and a change of about􀀀0.18 ms occurs inΔLOD series during this period.

关 键 词：日长变化 大气角动量 ENSO 拉尼娜 小波分析 

分 类 号：P183.3[天文地球—天文学]