The seismic waveform of the Yutian Ms7. 3 earthquake, Xinjiang on February 12, 2014 was recorded clearly and completely by the Digital Seismic Networks of Xinjiang, Qinghai, Tibet, and Xinjiang Hotan array, so the met...The seismic waveform of the Yutian Ms7. 3 earthquake, Xinjiang on February 12, 2014 was recorded clearly and completely by the Digital Seismic Networks of Xinjiang, Qinghai, Tibet, and Xinjiang Hotan array, so the method of joint location by regional seismic network and seismic array can be used to accurately determine the earthquake source location. The following technologies were used in the process of location： （ 1 ） We selected seismic stations equally located around the epicenter of the Ms 7. 3 earthquake with an average interval of about 15 degrees in the initial location. （2） The recording waveforms of Yutian seismic station were rotated to the radial and tangential directions to precisely obtain the arrival time of S-waves to determine the epicentral distance. （ 3） The velocity model was used in the determination of location of the epicenter, based on the historical records of earthquakes in the area within a radius of 1.0 ° from the source as the center, and the velocity model is obtained after re-fitting and calibration. （4） Based on the waveform records of the Hotan seismic array, the method of waveform beaming was used to determine the azimuths and perform the correction of the epicenter location with these azimuths. （5） The deterministic method was used to measure the source depth. Finally, it is concluded that the Yutian Ms 7. 3 main shock hypocenter location is 36. 197°N, 82. 467°E, focal depth 12km and original time 17：19：48. 2 μm. February 12, 2014.展开更多
The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated w...The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.展开更多
文摘为了适应未来无线通信系统中的设备多样性、高速率、低时延和低功率消耗的需要,新型波形研究成为第5代无线通信系统的关键技术之一。通用滤波多载波(Universal?filtered multicarrier,UFMC)是一种广泛研究的5G侯选波形。然而现有的UFMC研究只涉及UFMC?SISO的场景,UFMC?MIMO的可行性和性能分析仍然空缺,而MIMO波束成形必然是5G通信系统的重要场景,因此对UFMC?MIMO进行评估和研究具有重要价值。本文提出了一个UFMC?MIMO系统可行方案,包括发射机、接收机和波束成形实现算法。通过数学推导证明该方案能正确恢复发送端数据并通过仿真验证其性能。仿真结果表明,不论在加性高斯白噪声(Additive white Gaussian noise,AWGN)信道还是在多径信道下,UFMC?MIMO都具有比OFDM?MIMO更优越的性能,尤其在抗频偏鲁棒性上表现出很大的优越性,进而验证了UFMC?MIMO传输方案具备应用5G通信的能力。
基金funded by the Special Project of the Department of Earthquake Monitoring and Prediction,China Earthquake Administration(1309010)Seismic Network Youth Special Project,China Earthquake Administration(20140330,20130201)
文摘The seismic waveform of the Yutian Ms7. 3 earthquake, Xinjiang on February 12, 2014 was recorded clearly and completely by the Digital Seismic Networks of Xinjiang, Qinghai, Tibet, and Xinjiang Hotan array, so the method of joint location by regional seismic network and seismic array can be used to accurately determine the earthquake source location. The following technologies were used in the process of location： （ 1 ） We selected seismic stations equally located around the epicenter of the Ms 7. 3 earthquake with an average interval of about 15 degrees in the initial location. （2） The recording waveforms of Yutian seismic station were rotated to the radial and tangential directions to precisely obtain the arrival time of S-waves to determine the epicentral distance. （ 3） The velocity model was used in the determination of location of the epicenter, based on the historical records of earthquakes in the area within a radius of 1.0 ° from the source as the center, and the velocity model is obtained after re-fitting and calibration. （4） Based on the waveform records of the Hotan seismic array, the method of waveform beaming was used to determine the azimuths and perform the correction of the epicenter location with these azimuths. （5） The deterministic method was used to measure the source depth. Finally, it is concluded that the Yutian Ms 7. 3 main shock hypocenter location is 36. 197°N, 82. 467°E, focal depth 12km and original time 17：19：48. 2 μm. February 12, 2014.
基金Supported by the National Natural Science Foundation of China(No.40704003)the National 973 Program of China(No.2007CB714405)the Key Laboratory of Surveying and Mapping Technology on Island and Reef,State Bureau of Surveying and Mapping,China(No.2009B04)
文摘The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.
