Method for solving conditional nonlinear optimal disturbance based on analysis of four-dimensional set variation

Abstract

The invention discloses a method for solving conditional nonlinear optimal disturbance based on analysis of four-dimensional set variation. The method comprises the following steps: constructing a conditional nonlinear optimal disturbance objective function according to a marine forecasting model, and obtaining an objective function gradient formula; solving an increment matrix at the forecasting moment of the disturbance value matrix; rewriting an adjoint operator in the gradient formula, and rewriting the adjoint operator part in the gradient formula of the conditional nonlinear optimal disturbance objective function into a form related to a generalized ocean background state error covariance matrix; and solving the conditional nonlinear optimal disturbance of the ocean forecasting model through loop iteration. Compilation of an adjoint mode is avoided, portability is good, an error covariance matrix which is continuously updated is used, solving is more accurate, equivalence with a traditional algorithm is guaranteed when forecasting mode integration time is long and strong nonlinearity exists, the method is even superior to the traditional algorithm, the applicability of the CNOP method is greatly improved. And the invention is of great significance to development of atmosphere-ocean predictable research.

Description

technical field [0001] The invention relates to a method for solving conditional nonlinear optimal disturbance. In particular, it relates to a method for solving conditional nonlinear optimal disturbance based on analytical four-dimensional ensemble variation for atmospheric and ocean forecasting. Background technique [0002] Solving a class of fastest-growing initial perturbations is one of the key issues in studying the predictability of the atmosphere and ocean. Conditional Nonlinear Optimal Perturbation (CNOP) describes such a class of initial perturbations: under certain dynamic-physical constraints , so that the nonlinear system develops the largest at the forecast time. The CNOP method considers the influence of nonlinear physical processes on the motion of the atmosphere and ocean, and this method provides a new idea for improving the skill of atmosphere-ocean forecasting. [0003] The CNOP method is widely used in the study of the predictability of the atmosphere...

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Problems solved by technology

[0003] The CNOP method is widely used in the study of the predictability of the atmosphere and the ocean. How to solve the CNOP is a key problem in the application of this method. The traditional method of solving the CNOP needs to calculate the gradient information of the objective function through the adjoint model, and the development of the adjoint model And maintenance requires a lot of manpower and material resources, and poor portability, these shortcomings limit the business application of the CNOP method

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