A spectral analysis of predictability and error in an operational forecast system.

Abstract

A spectral analysis of error at 24, 48 and 72 hours in an operational forecast system is carried out for a winter and a summer month. The scale-dependent behavior of the error and the several factors governing error growth, namely the nonlinear production term, the nonlinear transfer of energy between scales and the model-related error source term are evaluated. It is found that the largest errors occur at low wavenumbers where the amplitude of the flow is largest, while the largest relative errors occur at high wavenumbers when error is approaching saturation. -from Author