P-spline smoothing for spatial data collected worldwide

Fedele Greco; Massimo Ventrucci; Elisa Castelli

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arXiv · 1711.05618

P-spline smoothing for spatial data collected worldwide

Fedele Greco·Massimo Ventrucci·Elisa Castelli

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Abstract

Spatial data collected worldwide at a huge number of locations are frequently used in environmental and climate studies. Spatial modelling for this type of data presents both methodological and computational challenges. In this work we illustrate a computationally efficient non parametric framework to model and estimate the spatial field while accounting for geodesic distances between locations. The spatial field is modelled via penalized splines (P-splines) using intrinsic Gaussian Markov Random Field (GMRF) priors for the spline coefficients. The key idea is to use the sphere as a surrogate for the Globe, then build the basis of B-spline functions on a geodesic grid system. The basis matrix is sparse and so is the precision matrix of the GMRF prior, thus computational efficiency is gained by construction. We illustrate the approach on a real climate study, where the goal is to identify the Intertropical Convergence Zone using high-resolution remote sensing data.

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BibTeX RIS

Fedele Greco, Massimo Ventrucci, Elisa Castelli. 2017-11-15. P-spline smoothing for spatial data collected worldwide. https://arxiv.org/abs/1711.05618

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