Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in ...Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth＇s rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD（length of day） were described. We applied MSSA（Multichannel Singular Spectrum Analysis） jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs（Principal components） strongly related to ENSO（El Nino southern oscillation） were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.展开更多
In this paper the multi-stage digit filter is used to analyse the data of Earth rotation represented by the length of day, ΔLOD. The results show that the interannual variations of Earth rotation, which are in the ti...In this paper the multi-stage digit filter is used to analyse the data of Earth rotation represented by the length of day, ΔLOD. The results show that the interannual variations of Earth rotation, which are in the time scale of several years but not quasi-periodic terms, exist in the long periodic fluctuations. They induce the relative variation in the length of day of 0.3×10^(-8).Comparing the series of length of day with the data of temperature departure of the sea surface in the equatorial area of the eastern Pacific, we found that the deceleration and acceleration of the interannual rate of Earth rotation are consistent with the warming up and down of sea temperature in the equatorial area very well. This means that every El Nio event always occurs after the turning of acceleration of the interannual rate of Earth rotation to deceleration.According to the strong interannual variation in the length of day and strong warming of the sea surface temperature in the equatorial area between 1982 and 1983, we analysed the data from atmospheric angular momentum (AAM) calculated by using the global zonal wind data, and found that the interannual variation in AAM has an excess of two to three months. We suggest that the interannual variations in Earth rotation and the El Nio events are probably responses of solid earth and ocean, respectively, to the anomaly of atmospheric circulation.It is also shown in oar analysis that the minimum of ΔLOD series, which is deduced from UT1 data observed regularly with astrometry, can predict the occurrence of the El Nio events for a long range forecast about one year.展开更多
Data sets of the changes of the length of day, the sea surface temperature in the eastern Pacific and of the sea level in Hong Long from tide gauge observations are used to analyze and reveal the reflections in the ob...Data sets of the changes of the length of day, the sea surface temperature in the eastern Pacific and of the sea level in Hong Long from tide gauge observations are used to analyze and reveal the reflections in the observations of the length of day and the sea level changes concerned with the premonitory phenomenon of next El Nino event. The results from this study indicate that a new El Nino event has been brewing with the ending of the strong La Nina event that started in early summer of 1998. The estimated formation period of the new El Nino event will begin before the end of 2000, and the peak period may be reached at around the end of 2001.展开更多
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
基金supported by Russian Foundation for Basic Research grants No. 17-05-00989, No. 16-05-00753,NRU HSE and visiting grants positions at Paris observatory and Wuhan university for the first authorpartially supported by grants by NSF/IGFA Belmont Forum Project (Grant No. ICER-1342644)the Chinese Academy of Sciences/SAFEA International Partnership Program for Creative Research Teams(Grant No. KZZD-EW-TZ-05)
文摘Earth＇s variable rotation is mainly produced by the variability of the AAM（atmospheric angular momentum）. In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth＇s rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD（length of day） were described. We applied MSSA（Multichannel Singular Spectrum Analysis） jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs（Principal components） strongly related to ENSO（El Nino southern oscillation） were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.
文摘In this paper the multi-stage digit filter is used to analyse the data of Earth rotation represented by the length of day, ΔLOD. The results show that the interannual variations of Earth rotation, which are in the time scale of several years but not quasi-periodic terms, exist in the long periodic fluctuations. They induce the relative variation in the length of day of 0.3×10^(-8).Comparing the series of length of day with the data of temperature departure of the sea surface in the equatorial area of the eastern Pacific, we found that the deceleration and acceleration of the interannual rate of Earth rotation are consistent with the warming up and down of sea temperature in the equatorial area very well. This means that every El Nio event always occurs after the turning of acceleration of the interannual rate of Earth rotation to deceleration.According to the strong interannual variation in the length of day and strong warming of the sea surface temperature in the equatorial area between 1982 and 1983, we analysed the data from atmospheric angular momentum (AAM) calculated by using the global zonal wind data, and found that the interannual variation in AAM has an excess of two to three months. We suggest that the interannual variations in Earth rotation and the El Nio events are probably responses of solid earth and ocean, respectively, to the anomaly of atmospheric circulation.It is also shown in oar analysis that the minimum of ΔLOD series, which is deduced from UT1 data observed regularly with astrometry, can predict the occurrence of the El Nio events for a long range forecast about one year.
文摘Data sets of the changes of the length of day, the sea surface temperature in the eastern Pacific and of the sea level in Hong Long from tide gauge observations are used to analyze and reveal the reflections in the observations of the length of day and the sea level changes concerned with the premonitory phenomenon of next El Nino event. The results from this study indicate that a new El Nino event has been brewing with the ending of the strong La Nina event that started in early summer of 1998. The estimated formation period of the new El Nino event will begin before the end of 2000, and the peak period may be reached at around the end of 2001.
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-
