Initial disturbance method based on ensemble data assimilation technology

Abstract

The present invention relates to an initial disturbance method based on an ensemble data assimilation technology, which comprises the following steps of: 1, constructing three ensemble components of WRFDA 3D-Var by disturbance information, minimizing a cost function by an iterating method so as to acquire a statistically optimal estimated value X of a real atmospheric condition; 2, setting irrelevant global ensemble forecast initial conditions to form a new cost function; 3, adding new observation into a WDF3DVAR assimilation system; 4, extracting a plurality of vertical profiles comprising each meteorological elements from the global scale ensemble forecast of ECMWF; and 5, operating the WRF3DVAR assimilation system with the new observation for each ensemble member, assimilating an observation set and a large-scale mode field set and generating final ensemble members for carrying out ensemble forecasting. The initial disturbance method based on the ensemble data assimilation technology has the beneficial effects that the ensemble members obtained by adopting the ensemble variational assimilation method can organically combine the storm scale with large-scale disturbance information; the cost function uses a mode as the dynamic constraint, so that ensemble disturbance has the physical and power harmony; and moreover, initial disturbance and lateral boundary disturbance are mutually coordinated.

Description

technical field [0001] The invention relates to weather forecasting, in particular to an initial perturbation method based on aggregated data assimilation technology. 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 l...

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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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