Abstract : Spectral representations uniquely define the covariance functions associated to random fields defined over spheres or spheres cross time. Covariance functions on spheres cross time are usually modeled under the assumptions of either spatial isotropy or axial symmetry, and the
assumption of temporal stationarity. This paper goes beyond these assumptions. In particular, we consider the problem of spatially anisotropic covariance functions on spheres. The crux of our criterion is to escape from the addition theorem for spherical harmonics. We also challenge
the problem of temporal nonstationarity in nonseparable space-time covariance functions, where space is the n-dimensional sphere.
https://hal.archives-ouvertes.fr/hal-01417668 Contributor : Anne EstradeConnect in order to contact the contributor Submitted on : Thursday, October 11, 2018 - 3:42:08 PM Last modification on : Friday, January 7, 2022 - 3:48:21 AM Long-term archiving on: : Saturday, January 12, 2019 - 3:11:26 PM