Ⅰ. INTRODUCTIONSince the strong El Nio event occurred at the end of 1982, which was characterized by the anomalous warming up of the sea surface water in equatorial area of eastern Pacific, the relationship between t...Ⅰ. INTRODUCTIONSince the strong El Nio event occurred at the end of 1982, which was characterized by the anomalous warming up of the sea surface water in equatorial area of eastern Pacific, the relationship between the variation of the rate of Earth rotation and the El Nio event has attracted more and more attention and some significant studies have been made. How-展开更多
Scientists pay great attention to different-time-scale signals in the lengllh of day （LOD） variations △LOD, which provide signatures of the Earth＇s interior structure, couplings among different layers, and potenti...Scientists pay great attention to different-time-scale signals in the lengllh of day （LOD） variations △LOD, which provide signatures of the Earth＇s interior structure, couplings among different layers, and potential excitations of ocean and atmosphere. In this study, based on the ensemble empirical mode decomposition （EEMD）, we analyzed the latest time series of △LOD data spanning from January 1962 to March 2015. We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms, 1.0 month and 0.19 ms, 0.5 yr and 0.22 ms, 1.0 yr and 0.18 ms, 2.28 yr and 0.03 ms, 5.48 yr and 0.05 ms, respectively, in coincidence with the results of predecessors. In addition, some signals that were previously not definitely observed by predecessors were detected in this study, with periods and amplitudes of 9.13 d and 0.12 ms, 13.69 yr and 0.10 ms, respectively. The mechanisms of the LOD fluctuations of these two signals are still open.展开更多
The long-term fluctuation of the Schwabe period (LSP) of sunspots number (SSN) has been found to have high correlation with the variation of the length-of-day (LOD) in low frequency by using the data of smoothed month...The long-term fluctuation of the Schwabe period (LSP) of sunspots number (SSN) has been found to have high correlation with the variation of the length-of-day (LOD) in low frequency by using the data of smoothed monthly mean SSN during 1818-1999 and the method of wavelet transform. Analyses indicate that the maximum correlation coefficient between the series of LSP and LOD during 1892-1997 is about 0.9, with a time lag of about 5 years for the LOD related to the LSP. Though the maximum correlation coefficients between the LSP and the other two LOD series (1818-1997) reduce to about 0.4, they remain over the thresholds of 95% confidence level. This suggests new evidence for possible impact of solar activity on the long-term fluctuation of the earth rotation.展开更多
文摘Ⅰ. INTRODUCTIONSince the strong El Nio event occurred at the end of 1982, which was characterized by the anomalous warming up of the sea surface water in equatorial area of eastern Pacific, the relationship between the variation of the rate of Earth rotation and the El Nio event has attracted more and more attention and some significant studies have been made. How-
基金supported by National 973 Project China (2013CB733305)National Natural Science Foundation of China (NSFCs) (41174011,41429401,41210006,41128003,41021061)
文摘Scientists pay great attention to different-time-scale signals in the lengllh of day （LOD） variations △LOD, which provide signatures of the Earth＇s interior structure, couplings among different layers, and potential excitations of ocean and atmosphere. In this study, based on the ensemble empirical mode decomposition （EEMD）, we analyzed the latest time series of △LOD data spanning from January 1962 to March 2015. We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms, 1.0 month and 0.19 ms, 0.5 yr and 0.22 ms, 1.0 yr and 0.18 ms, 2.28 yr and 0.03 ms, 5.48 yr and 0.05 ms, respectively, in coincidence with the results of predecessors. In addition, some signals that were previously not definitely observed by predecessors were detected in this study, with periods and amplitudes of 9.13 d and 0.12 ms, 13.69 yr and 0.10 ms, respectively. The mechanisms of the LOD fluctuations of these two signals are still open.
基金This work was supported in part by the National Natural Science Foundation of China (Grant Nos. 19973011 and 19833030), the Major Project of Chinese Academy of Sciences (Grant No. KJ951-1-304) and the Shanghai Science and Technology Department Foundation
文摘The long-term fluctuation of the Schwabe period (LSP) of sunspots number (SSN) has been found to have high correlation with the variation of the length-of-day (LOD) in low frequency by using the data of smoothed monthly mean SSN during 1818-1999 and the method of wavelet transform. Analyses indicate that the maximum correlation coefficient between the series of LSP and LOD during 1892-1997 is about 0.9, with a time lag of about 5 years for the LOD related to the LSP. Though the maximum correlation coefficients between the LSP and the other two LOD series (1818-1997) reduce to about 0.4, they remain over the thresholds of 95% confidence level. This suggests new evidence for possible impact of solar activity on the long-term fluctuation of the earth rotation.
