%0 Journal Article
%T DETECTION OF LONG-PERIOD CORE MODES BY USING THE DATA FROM GLOBAL SUPERCONDUCTING GRAVIMETERS<br>利用全球超导重力仪数据检测长周期核模
%A XU Jian-Qiao
%A SUN He-Ping
%A FU Rong-Shan Key Laboratory of Dynamic Geodesy
%A Institute of Geodesy
%A Geophysics
%A Chinese Academy of Sciences
%A Wuhan
%A China College of Earth
%A Space Sciences
%A University of Science
%A Technology of China
%A Hefei
%A China
%A <br>徐建桥
%A 孙和平
%A 傅容珊
%J 地球物理学报
%D 2005
%I 
%X Possibility of detection of the long-period core modes is discussed by using the long-term gravity observations recorded with 13 superconducting gravimeters (SGs) in a worldwide network of the Global Geodynamics Projects. Identical techniques are used to remove the luni-solar gravity tides, the long-term trends of instrument drift, and the effects of atmospheric pressure from all 13 SG data sets. The power spectral density of each data set, as well as the product spectral density of all the data sets, is evaluated. The background noise levels in various non-tidal bands are estimated and analyzed. The results indicate that the background noise level of the global SG observations is 0 0649 nm/s2 in the inter-tidal band from 0 047 to 0 075cph, 0 0350 nm/s2 in another inter-tidal band from 0 089 to 0 117cph, and 0 0138 nm/s2 in the sub-tidal band from 0 172 to 0 333cph. The magnitude thresholds of any global harmonic signals, which may be detected by the global SGs, in these three non-tidal bands are 0 0416, 0 0231and 0 0098 nm/s2, respectively. It implies that the signals, related to the long-period core modes, may be identified in the global SG observations, if they exist. The spectral peaks of the global harmonic signals with periods of 16 55, 15 79, 11 00 and 10 09h are detected in the two inter-tidal bands of the global SG records; and they may come from the long-period oscillations in the fluid outer core of the Earth. In the sub-tidal band, there is no obvious peak relating to the Slichter triplet claimed by Smylie in 1992 Instead, 8 spectral peaks of global harmonic signatures significantly emerge from the background noise. Comparing their periods with those of the Slichter triplet predicted theoretically, it may be concluded that the Slichter triplet is one of the possible resources of three peaks of them.
%K Global Geodynamics Projects
%K Superconducting gravimeters
%K Long-period core modes
%K Product spectral density<br>全球地球动力学计划
%K 超导重力仪
%K 长周期核模
%K 积谱密度
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=1E44AE713D8A6DE0&jid=14DC41C59CBF6770055A7D610D53AE46&aid=C889C2292607105D&yid=2DD7160C83D0ACED&vid=B6DA1AC076E37400&iid=CA4FD0336C81A37A&sid=CB423C9A71560A74&eid=E44E40A2398D4F2A&journal_id=0001-5733&journal_name=地球物理学报&referenced_num=3&reference_num=36