A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-sca...A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-scale groundwater pumping in North China, glacier-water flow and storage in Tianshan region, and pre seismic gravity changes of the 2008 MsS. 0 Wenchuan earthquake, which are spatially similar to co-seismi, changes but reversed in sign. These features are also shown in the result of the satellite-based GRACE obser vation, after a height effect is corrected with GPS data.展开更多
The North-South Seismic Belt was analyzed using gravity observation data from 2011 to 2015, and the nontidal analysis results show that there was a nonlinear gravity change at both the Chengdu and Guza seismostations ...The North-South Seismic Belt was analyzed using gravity observation data from 2011 to 2015, and the nontidal analysis results show that there was a nonlinear gravity change at both the Chengdu and Guza seismostations one month before the Leshan M5.0 earthquake.展开更多
On the： basis of wavelet theory, we propose an outlier-detection algorithm for satellite gravity ometry by applying a wavelet-shrinkage-de-noising method to some simulation data with white noise and ers. The result S...On the： basis of wavelet theory, we propose an outlier-detection algorithm for satellite gravity ometry by applying a wavelet-shrinkage-de-noising method to some simulation data with white noise and ers. The result Shows that this novel algorithm has a 97% success rate in outlier identification and that be efficiently used for pre-processing real satellite gravity gradiometry data.展开更多
By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By anal...By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By analyzing these images, we found that the gravity in Liaodong peninsula area showed an obvious increase of 80 × 10^-8ms^-2 during about one- and-half year before the 2011 Japan Mwg. 0 earthquake, and a rapid decrease after the earthquake. This gravity variation is similar to that observed previously for the 1976 Tangshan 1147.8 earthquake.展开更多
Mass variations in terrestrial water storage（TWS） obtained from eight years of satellite data from the Gravity Recovery and Climate Experiment（GRACE） are used to describe low frequency TWS through Empirical Orthog...Mass variations in terrestrial water storage（TWS） obtained from eight years of satellite data from the Gravity Recovery and Climate Experiment（GRACE） are used to describe low frequency TWS through Empirical Orthogonal Function（EOF） analysis. Results of the second seasonal EOF mode show the influence of the Meiyu season. Annual variability is clearly shown in the precipitation distribution over China, and two new patterns of interannual variability are presented for the first time from observations, where two periods of abrupt acceleration are seen in 2004 and 2008. GRACE successfully measures drought events in southern China, and in this respect, an association with the Arctic Oscillation and El Nino-Southern Oscillation is discussed. This study demonstrates the unique potential of satellite gravity measurements in monitoring TWS variations and large-scale severe drought in China.展开更多
This paper reports on a study of the methodology of external calibration of GOCE data, using regional terrestrial-gravity data. Three regions around the world are selected in the numerical experiments. The result indi...This paper reports on a study of the methodology of external calibration of GOCE data, using regional terrestrial-gravity data. Three regions around the world are selected in the numerical experiments. The result indicates that this calibration method is feasible. The effect is best with an accuracy of scale factor at 10 -2 level, in Australia, where the area is smooth and the gravity data points are dense. The accuracy is one order of magnitude lower in both Canada, where the area is smooth but the data points are sparse, and Norway, where the area is rather tough and the data points are sparse.展开更多
To study the characteristics of gravity variations in and near the North-South Seismic Belt before the 2013 Lushan earthquake,we used the geopotential-field models based on monthly data of the RI.~5 GRACE satellite to...To study the characteristics of gravity variations in and near the North-South Seismic Belt before the 2013 Lushan earthquake,we used the geopotential-field models based on monthly data of the RI.~5 GRACE satellite to calculate the gravity changes. Here we present the patterns of annually cumulative variation, differentiatial variation and secular trend, as well as the continuous time-series at 4 characteristic sites during 2004 -2012. The result shows that the anomalous positive-to-negative transition zone, in which the epicenter of the 2008 Wenchuan earthquake was located, did not show any new gravity change before the Lushan earthquake, though located in the same zone.展开更多
基金supported by the National Natural Science Foundation of China (41004030)
文摘A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-scale groundwater pumping in North China, glacier-water flow and storage in Tianshan region, and pre seismic gravity changes of the 2008 MsS. 0 Wenchuan earthquake, which are spatially similar to co-seismi, changes but reversed in sign. These features are also shown in the result of the satellite-based GRACE obser vation, after a height effect is corrected with GPS data.
基金supported by the Director Foundation of Institute of Seismology,China Earthquake Administration(201326123)the National Natural Science Foundation of China(41204058,41474064)the Ministry of Science and Technology major instrument special sub topic(2012YQ10022506)
文摘The North-South Seismic Belt was analyzed using gravity observation data from 2011 to 2015, and the nontidal analysis results show that there was a nonlinear gravity change at both the Chengdu and Guza seismostations one month before the Leshan M5.0 earthquake.
基金supported by the Director Foundation of the Institute of Seismology,China Earthquake Administration (IS201126025)The Basis Research Foundation of Key laboratory of Geospace Environment & Geodesy Ministry of Education,China (10-01-09)
文摘On the： basis of wavelet theory, we propose an outlier-detection algorithm for satellite gravity ometry by applying a wavelet-shrinkage-de-noising method to some simulation data with white noise and ers. The result Shows that this novel algorithm has a 97% success rate in outlier identification and that be efficiently used for pre-processing real satellite gravity gradiometry data.
基金supported by the Special Social Commonweal Research of the State( 2005DIB3J120) the Director Foundation of the Institute of Seismology,China Earthquake Administration ( IS200956045) Special Foundation for Earthquake Monitoring and Tracing in North China
文摘By using absolute and relative-gravity data recorded by the gravity network in North China, we obtained some large-scale and high-spatial-resolution images of gravity variation in this area for the first time. By analyzing these images, we found that the gravity in Liaodong peninsula area showed an obvious increase of 80 × 10^-8ms^-2 during about one- and-half year before the 2011 Japan Mwg. 0 earthquake, and a rapid decrease after the earthquake. This gravity variation is similar to that observed previously for the 1976 Tangshan 1147.8 earthquake.
基金supported by China National Science Funds(41474064,41504066)
文摘Mass variations in terrestrial water storage（TWS） obtained from eight years of satellite data from the Gravity Recovery and Climate Experiment（GRACE） are used to describe low frequency TWS through Empirical Orthogonal Function（EOF） analysis. Results of the second seasonal EOF mode show the influence of the Meiyu season. Annual variability is clearly shown in the precipitation distribution over China, and two new patterns of interannual variability are presented for the first time from observations, where two periods of abrupt acceleration are seen in 2004 and 2008. GRACE successfully measures drought events in southern China, and in this respect, an association with the Arctic Oscillation and El Nino-Southern Oscillation is discussed. This study demonstrates the unique potential of satellite gravity measurements in monitoring TWS variations and large-scale severe drought in China.
基金supported by the Director Foundation of the Institute of Seismology,China Earthquake Administration (IS201126025)The Basis Research Foundation of Key laboratory of Geospace Environment & Geodesy Ministry of Education,China (10-01-09)
文摘This paper reports on a study of the methodology of external calibration of GOCE data, using regional terrestrial-gravity data. Three regions around the world are selected in the numerical experiments. The result indicates that this calibration method is feasible. The effect is best with an accuracy of scale factor at 10 -2 level, in Australia, where the area is smooth and the gravity data points are dense. The accuracy is one order of magnitude lower in both Canada, where the area is smooth but the data points are sparse, and Norway, where the area is rather tough and the data points are sparse.
基金supported by the China Earthquake Administration Special Basic Scientific Research Business Expenses(IS201116022)the National Natural Science Foundation of China(40704009,41004030)
文摘To study the characteristics of gravity variations in and near the North-South Seismic Belt before the 2013 Lushan earthquake,we used the geopotential-field models based on monthly data of the RI.~5 GRACE satellite to calculate the gravity changes. Here we present the patterns of annually cumulative variation, differentiatial variation and secular trend, as well as the continuous time-series at 4 characteristic sites during 2004 -2012. The result shows that the anomalous positive-to-negative transition zone, in which the epicenter of the 2008 Wenchuan earthquake was located, did not show any new gravity change before the Lushan earthquake, though located in the same zone.
