We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation per...We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation period.Using ADCP observations,satellite wind and heat flux measurements,and high-resolution model assimilation products,we studied the response of the upper ocean to typhoons.The first typhoon,Nuri,passed over one of the moorings,resulting in strong Ekman divergence and significant surface cooling.The cooling of surface water lagged the typhoon wind forcing about one day and lasted about five days.The second typhoon,Sinlaku,moved northward east of the Luzon Strait,and did not directly impact currents near the observation regions.Sinlaku increased anomalous surface water transport exchange across the Luzon Strait,which modulated the surface layer current of the Kuroshio.展开更多
Spectral decomposition using the method of Matching Pursuit Decomposition （MPD） for PP- and PS-wave data has higher resolution and higher consistency over the entire time-frequency plane. The MPD algorithm avoids th...Spectral decomposition using the method of Matching Pursuit Decomposition （MPD） for PP- and PS-wave data has higher resolution and higher consistency over the entire time-frequency plane. The MPD algorithm avoids the problems of inaccurate analytic time point and the time window size choice that may occur during a Fourier transform. The PP-wave attenuation is greater than the PS-wave attenuation while propagating through gas reservoirs. There are some stronger amplitude low-frequency shadows on the PP-wave single frequency sections beneath gas reservoirs which are not seen on corresponding PS- wave single frequency sections. Therefore, hydrocarbons are predicted from comparing the behavior on both frequency sections. The time-frequency analysis for multi-component data is decomposed by MPD for data from northeast China containing rich gas reservoirs. The gas response character is analyzed on different wave mode single frequency sections. We describe the MPD algorithm, compare it to other spectral decomposition methods, and show some examples of detecting low-frequency shadows beneath gas reservoirs.展开更多
In the present paper,from the second order partial differential equations for solving the magnetotelluric(MT) fields of general anisotropic medium,we first obtained the second order partial differential equations for ...In the present paper,from the second order partial differential equations for solving the magnetotelluric(MT) fields of general anisotropic medium,we first obtained the second order partial differential equations for some anisotropic media with special conductivity(e.g.diagonal anisotropy,transverse anisotropy,azimuthal anisotropy,etc.) by simplifying the electrical conductivity tensor of anisotropic medium.And then we obtained the analytic solutions to MT fields for the case of transverse and azimuthal anisotropy through converting the conductivity parameter based on that of diagonal anisotropy.We further discussed the influence of the selection of integral limit and step length on precision in solving the analytic solutions for MT fields of isotropic medium.Finally,we presented the MT responses of two transverse and azimuthal anisotropic media as well as some applications of the analytic solutions to MT fields of anisotropic medium.展开更多
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos.KZCX1-YW-12-01KZCX2-YW-BR-04)+1 种基金the National Natural Science Foundation of China (Nos.40876007,40806006)the National High Technology Research and Development Program of China (863 Program) (No.2008AA09A402)
文摘We deployed two ADCP mooring systems west of the Luzon Strait in August 2008,and measured the upper ocean currents at high frequency.Two typhoons passed over the moorings during approximately one-month observation period.Using ADCP observations,satellite wind and heat flux measurements,and high-resolution model assimilation products,we studied the response of the upper ocean to typhoons.The first typhoon,Nuri,passed over one of the moorings,resulting in strong Ekman divergence and significant surface cooling.The cooling of surface water lagged the typhoon wind forcing about one day and lasted about five days.The second typhoon,Sinlaku,moved northward east of the Luzon Strait,and did not directly impact currents near the observation regions.Sinlaku increased anomalous surface water transport exchange across the Luzon Strait,which modulated the surface layer current of the Kuroshio.
文摘Spectral decomposition using the method of Matching Pursuit Decomposition （MPD） for PP- and PS-wave data has higher resolution and higher consistency over the entire time-frequency plane. The MPD algorithm avoids the problems of inaccurate analytic time point and the time window size choice that may occur during a Fourier transform. The PP-wave attenuation is greater than the PS-wave attenuation while propagating through gas reservoirs. There are some stronger amplitude low-frequency shadows on the PP-wave single frequency sections beneath gas reservoirs which are not seen on corresponding PS- wave single frequency sections. Therefore, hydrocarbons are predicted from comparing the behavior on both frequency sections. The time-frequency analysis for multi-component data is decomposed by MPD for data from northeast China containing rich gas reservoirs. The gas response character is analyzed on different wave mode single frequency sections. We describe the MPD algorithm, compare it to other spectral decomposition methods, and show some examples of detecting low-frequency shadows beneath gas reservoirs.
基金supported by the National Natural Science Foundation of China(Grant No.40774035)
文摘In the present paper,from the second order partial differential equations for solving the magnetotelluric(MT) fields of general anisotropic medium,we first obtained the second order partial differential equations for some anisotropic media with special conductivity(e.g.diagonal anisotropy,transverse anisotropy,azimuthal anisotropy,etc.) by simplifying the electrical conductivity tensor of anisotropic medium.And then we obtained the analytic solutions to MT fields for the case of transverse and azimuthal anisotropy through converting the conductivity parameter based on that of diagonal anisotropy.We further discussed the influence of the selection of integral limit and step length on precision in solving the analytic solutions for MT fields of isotropic medium.Finally,we presented the MT responses of two transverse and azimuthal anisotropic media as well as some applications of the analytic solutions to MT fields of anisotropic medium.
