The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,suc...The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,such as surface deformation,groundwater storage changes,and mass migration before and after earthquakes.Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region(SYR)from 2015 to 2017,we determine a time series of degree 120 gravity fields using the localized spherical harmonic(Slepian)basis functions.Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR.The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features.The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site.展开更多
We introduce a family of orthogonal functions,termed as generalized Slepian functions(GSFs),closely related to the time-frequency concentration problem on a unit disk in D.Slepian[19].These functions form a complete o...We introduce a family of orthogonal functions,termed as generalized Slepian functions(GSFs),closely related to the time-frequency concentration problem on a unit disk in D.Slepian[19].These functions form a complete orthogonal system in L_(ωα)^(2)(−1,1)with̟ω_(α)(x)=(1−x)^(α),α>−1,and can be viewed as a generalization of the Jacobi polynomials with parameter(α,0).We present various analytic and asymptotic properties of GSFs,and study spectral approximations by such functions.展开更多
基金the National Natural Science Foundation of China(Nos.41974095,41774090,and U1939205)the Special Fund of the Institute of Geophysics,China Earthquake Administration(Nos.DQJB20X09,and DQJB21R30)The first author acknowledges support from the China Postdoctoral Science Foundation(No.2018M641424)。
文摘The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,such as surface deformation,groundwater storage changes,and mass migration before and after earthquakes.Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region(SYR)from 2015 to 2017,we determine a time series of degree 120 gravity fields using the localized spherical harmonic(Slepian)basis functions.Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR.The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features.The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site.
基金supported by Singapore AcRF Tier 1 Grant RG58/08,Singapore MOE Grant T207B2202Singapore NRF2007IDM-IDM002-010.
文摘We introduce a family of orthogonal functions,termed as generalized Slepian functions(GSFs),closely related to the time-frequency concentration problem on a unit disk in D.Slepian[19].These functions form a complete orthogonal system in L_(ωα)^(2)(−1,1)with̟ω_(α)(x)=(1−x)^(α),α>−1,and can be viewed as a generalization of the Jacobi polynomials with parameter(α,0).We present various analytic and asymptotic properties of GSFs,and study spectral approximations by such functions.
