Will Kleiber Department of Statistics University of Washington Seattle Title: Mat\'ern Cross-Covariance Functions for Multivariate Random Fields Abstract: We introduce a flexible parametric family of matrix-valued covariance functions for multivariate spatial random fields, where each constituent component is a Mat\'ern process. The model parameters are interpretable in terms of process variance, smoothness, correlation length, and co-located correlation coefficients, which can be positive or negative. Both the marginal and the cross-covariance functions are of the Mat\'ern type. In a data example on error fields for numerical predictions of surface pressure and temperature over the Pacific Northwest, a parsimonious bivariate Mat\'ern model compares favorably to the traditional linear model of coregionalization.