Atmospheric CO2 concentrations from January 2010 to December 2010 were simulated using the GEOS-Chem(Goddard Earth Observing System-Chemistry) model and the results were compared to satellite Gases Observing Satellite...Atmospheric CO2 concentrations from January 2010 to December 2010 were simulated using the GEOS-Chem(Goddard Earth Observing System-Chemistry) model and the results were compared to satellite Gases Observing Satellite(GOSAT) and ground-based the Total Carbon Column Observing Network(TCCON) data. It was found that CO2 concentrations based on GOSAT satellite retrievals were generally higher than those simulated by GEOS-Chem. The differences over the land area in January and April ranged from 1 to 2 ppm, and there were major differences in June and August. At high latitudes in the Northern Hemisphere in June, as well as south of the Sahara, the difference was greater than 5 ppm. In the high latitudes of the Northern Hemisphere the model results were higher than the GOSAT retrievals, while in South America the satellite data were higher. The trend of the difference in the high latitudes of the Northern Hemisphere and the Saharan region in August was opposite to June. Maximum correlation coefficients were found in April, reaching 0.72, but were smaller in June and August. In January, the correlation coefficient was only 0.36. The comparisons between GEOS-Chem data and TCCON observations showed better results than the comparison between GEOS and GOSAT. The correlation coefficients ranged between 0.42(Darwin) and 0.92(Izana). Analysis of the results indicated that the inconsistency between satellite observations and model simulations depended on inversion errors caused by data inaccuracies of the model simulation's inputs, as well as the mismatch of satellite retrieval model input parameters.展开更多
The April 20,2013,Ms 7.0 Lushan Earthquake was a major earthquake that followed the Ms 8.0 Wenchuan Earthquake on May 12,2008.Frequent earthquakes have caused heavy casualties and property loss in Western Sichuan.Eart...The April 20,2013,Ms 7.0 Lushan Earthquake was a major earthquake that followed the Ms 8.0 Wenchuan Earthquake on May 12,2008.Frequent earthquakes have caused heavy casualties and property loss in Western Sichuan.Earthquake disasters are often closely related to the amplification effect of ground motion.Studying the ground motion characteristics of near-surface geological structures helps to understand the distribution of potential earthquake disasters.In this study,we investigated ground motion amplification in the downtown area of Lushan using numerical simulation and aftershock data from the Lushan Earthquake.Using the Lushan earthquake aftershock data from nine seismic stations distributed in the area,the amplification effect of the sites was determined using the"reference site spectral ratio"method.The results show that the frequency of the ground motion amplification in the area was in the range 5–10 Hz,and the corresponding amplification peak was from 3 to 14.Among the study sites,the amplification(14 times)at L07 was the most prominent.To study further the amplification characteristics,shear-wave velocity models for the structures under these sites were established using passive-source Rayleigh surfacewave exploration.One-dimensional(1 D)and two-dimensional(2 D)seismic amplification effects were simulated using horizontally propagating shear-wave modeling.Except Site L07,the 1 D simulation results of each site well reflected the variation feature of the seismic amplification on the frequency band below the observed peak frequency,although the overall simulated amplification peaks were smaller than the observed results.The 2 D simulation of the remarkable amplification phenomenon at L07 was in better agreement with the observation result than was the 1 D simulation,indicating that the seismic amplification in the Modong area is influenced by lateral variation of the Quaternary sediments.展开更多
The details of seismic monitoring network and seismological work in Thailand, including some information on felt earthquakes that occurred from 2000 to August 2001, are reported here.
High resolution remote sensing data has been applied in many fields such as national security, economic construction and in the daily life of the general public around the world, creating a huge market. Commercial rem...High resolution remote sensing data has been applied in many fields such as national security, economic construction and in the daily life of the general public around the world, creating a huge market. Commercial remote sensing cameras have been developed vigorously throughout the world over the last few decades, resulting in resolutions down to 0.31 m. In 2010, the Chinese government approved the implementation of the China High-resolution Earth Observation System(CHEOS) Major Special Project, giving priority to development of high resolution remote sensing satellites. More than half of CHEOS has been constructed to date and 5 satellites operate in orbit. These cameras have different characteristics. A number of innovative technologies have been adopted, which have led to camera performance increasing in leaps and bounds. The products and the production capability enables the remote sensing technical level to increase making it on a par with Europe and the US.展开更多
Near-surface earth resistivity and underground water level anomalies were recorded at Qingdao seismic observatory of Shandong Province before and after the MS8.0 Wenchuan Earthquake of May 12,2008.The observed data of...Near-surface earth resistivity and underground water level anomalies were recorded at Qingdao seismic observatory of Shandong Province before and after the MS8.0 Wenchuan Earthquake of May 12,2008.The observed data of earth resistivity at the observatory revealed that the underground water level dropped and the resistivity increased.It is postulated that in the special tectonic setting at Qingdao observatory,the variation of stress and strain caused the change of water level beneath the station,thus,leading to the variation of earth resistivity.The relationship between the variation of stress field and the change of earth resistivity before earthquake is analyzed.展开更多
The amplitudes of the Earth＇s free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period fr...The amplitudes of the Earth＇s free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a su- perconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3-5 mHz frequency band. The scalar seismic moment M~ has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have mi- nor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inver- sion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data.展开更多
基金supported by the National High Technology Research and Development Program of China (Grant No. 2013AA122002)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-EW-QN207)the National Basic Research Program of China (Grant Nos. 2010CB428403 and 2009CB421407)
文摘Atmospheric CO2 concentrations from January 2010 to December 2010 were simulated using the GEOS-Chem(Goddard Earth Observing System-Chemistry) model and the results were compared to satellite Gases Observing Satellite(GOSAT) and ground-based the Total Carbon Column Observing Network(TCCON) data. It was found that CO2 concentrations based on GOSAT satellite retrievals were generally higher than those simulated by GEOS-Chem. The differences over the land area in January and April ranged from 1 to 2 ppm, and there were major differences in June and August. At high latitudes in the Northern Hemisphere in June, as well as south of the Sahara, the difference was greater than 5 ppm. In the high latitudes of the Northern Hemisphere the model results were higher than the GOSAT retrievals, while in South America the satellite data were higher. The trend of the difference in the high latitudes of the Northern Hemisphere and the Saharan region in August was opposite to June. Maximum correlation coefficients were found in April, reaching 0.72, but were smaller in June and August. In January, the correlation coefficient was only 0.36. The comparisons between GEOS-Chem data and TCCON observations showed better results than the comparison between GEOS and GOSAT. The correlation coefficients ranged between 0.42(Darwin) and 0.92(Izana). Analysis of the results indicated that the inconsistency between satellite observations and model simulations depended on inversion errors caused by data inaccuracies of the model simulation's inputs, as well as the mismatch of satellite retrieval model input parameters.
基金supported by the National Natural Science Foundation of China(No.41774059)the Sichuan Science and Technology Program(No.2018JY0005)
文摘The April 20,2013,Ms 7.0 Lushan Earthquake was a major earthquake that followed the Ms 8.0 Wenchuan Earthquake on May 12,2008.Frequent earthquakes have caused heavy casualties and property loss in Western Sichuan.Earthquake disasters are often closely related to the amplification effect of ground motion.Studying the ground motion characteristics of near-surface geological structures helps to understand the distribution of potential earthquake disasters.In this study,we investigated ground motion amplification in the downtown area of Lushan using numerical simulation and aftershock data from the Lushan Earthquake.Using the Lushan earthquake aftershock data from nine seismic stations distributed in the area,the amplification effect of the sites was determined using the"reference site spectral ratio"method.The results show that the frequency of the ground motion amplification in the area was in the range 5–10 Hz,and the corresponding amplification peak was from 3 to 14.Among the study sites,the amplification(14 times)at L07 was the most prominent.To study further the amplification characteristics,shear-wave velocity models for the structures under these sites were established using passive-source Rayleigh surfacewave exploration.One-dimensional(1 D)and two-dimensional(2 D)seismic amplification effects were simulated using horizontally propagating shear-wave modeling.Except Site L07,the 1 D simulation results of each site well reflected the variation feature of the seismic amplification on the frequency band below the observed peak frequency,although the overall simulated amplification peaks were smaller than the observed results.The 2 D simulation of the remarkable amplification phenomenon at L07 was in better agreement with the observation result than was the 1 D simulation,indicating that the seismic amplification in the Modong area is influenced by lateral variation of the Quaternary sediments.
文摘The details of seismic monitoring network and seismological work in Thailand, including some information on felt earthquakes that occurred from 2000 to August 2001, are reported here.
文摘High resolution remote sensing data has been applied in many fields such as national security, economic construction and in the daily life of the general public around the world, creating a huge market. Commercial remote sensing cameras have been developed vigorously throughout the world over the last few decades, resulting in resolutions down to 0.31 m. In 2010, the Chinese government approved the implementation of the China High-resolution Earth Observation System(CHEOS) Major Special Project, giving priority to development of high resolution remote sensing satellites. More than half of CHEOS has been constructed to date and 5 satellites operate in orbit. These cameras have different characteristics. A number of innovative technologies have been adopted, which have led to camera performance increasing in leaps and bounds. The products and the production capability enables the remote sensing technical level to increase making it on a par with Europe and the US.
基金supported by Natural Science Fondation of Shandong Province(ZR2010DM008)National Natural Science Foundation(40534023, 41074047),China
文摘Near-surface earth resistivity and underground water level anomalies were recorded at Qingdao seismic observatory of Shandong Province before and after the MS8.0 Wenchuan Earthquake of May 12,2008.The observed data of earth resistivity at the observatory revealed that the underground water level dropped and the resistivity increased.It is postulated that in the special tectonic setting at Qingdao observatory,the variation of stress and strain caused the change of water level beneath the station,thus,leading to the variation of earth resistivity.The relationship between the variation of stress field and the change of earth resistivity before earthquake is analyzed.
基金supported by the National Basic Research Program of China (Grant No. 2014CB845902)National Natural Science Foundation of China (Grant Nos. 41174022, 4127408 and 41021003)
文摘The amplitudes of the Earth＇s free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a su- perconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3-5 mHz frequency band. The scalar seismic moment M~ has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have mi- nor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inver- sion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data.
