A Disturbance Method for Storm Scale Ensemble Forecast

Abstract

The invention relates to a storm scale ensemble forecast perturbation method. Observation data analysis, assimilation and numerical simulation are used as major measures; an ensemble forecast method is combined with severe convection weather forecast; and by aiming at the essential differences of the global medium-range ensemble forecast and the storm scale severe convection ensemble forecast, the final goal of building a storm scale ensemble forecast system which is applicable to various kinds of storm systems and constructs the perturbation scheme in a self-adaptive way according to the real-time developed severe convection system features is achieved. The method has the beneficial effects that through a variational assimilation ensemble, the ensemble perturbation realizes the physical and power harmony; the ensemble dispersion degree of the boundary layer mode variable is improved by a random physical harmony method; through self-adaptive selection on perturbation variables sensitive to the real-time developed storm system, the variable with the most obvious influence and the highest sensitivity on the storm development is selected for perturbation; high pertinence is realized; and the ensemble dispersion degree is also improved.

Description

technical field [0001] The invention relates to the technical field of weather forecasting, in particular to a disturbance method for storm-scale ensemble forecasting. Background technique [0002] A series of studies in the past have shown that storm-scale ensemble forecasting is feasible and effective, but the perturbation methods of various storm-scale ensemble forecasting systems still need to be perfected. For example, the storm-scale ensemble forecast system of the Center for Storm Analysis and Prediction (CAPS) in the United States can improve the forecast score by increasing the number of members and resolution, but its ensemble disturbance scheme is fixed, that is, the initial disturbance of each ensemble member adopts a fixed disturbance Amplitude, and matched with a specific physical scheme; the lateral boundary conditions of some ensemble members are provided by the short-term forecast of the NAM model, and the same lateral boundary conditions among members will ...

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Problems solved by technology

[0003] Because the evolution of the initial error over time is significantly different in baroclinic instability and convective instability, the initial disturbance constructed by the medium-term ensemble disturbance method cannot grow rapidly in the convective system, that is, the initial disturbance structure is not consistent with the development of the storm system. On the other hand, the incompatibility between the initial disturbance of the storm scale and the scale of the side boundary disturbance will also limit the growth of the initial disturbance and the dispersion of the set

Multi-physics processes and multi-model ensembles help to improve the dispersion problem, but the precipitation forecast variables in the micro-physics scheme of the model and the threshold condition judgment of the micro-physics process are different, and have a significant impact on the precipitation intensity and fall area forecast. For different types of storm systems that occur in real time, it is blind to use a fixed set configuration to select different modes of microphysics schemes

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