Typhoon dynamic balance constrained variational assimilation method based on WRF (Weather Research and Forecasting) mode

Abstract

The invention relates to a typhoon dynamic balance constrained variational assimilation method based on a WRF (Weather Research and Forecasting) mode. The method comprises the following steps that i, a dynamic equilibrium equation is obtained according to an atmospheric primitive motion equation under the vertical coordinate sigma of the WRF mode; ii, the dynamic equilibrium equation is expressed as a weak constraint penalty term Je by using a weak constraint condition method, and added to a cost function of a WRFDA (WRF Data Assimilation) system, then a new variational cost function is obtained; iii, the new variational assimilation cost function is solved by using a conjugate gradient method to obtain the minimum value of the cost function, and then an assimilation analysis field is obtained. The method disclosed by the invention can effectively improve effects of various observational data in typhoon assimilation to improve the typhoon forecasting ability.

Description

technical field [0001] The invention relates to a variational assimilation method for a typhoon under a dynamic constraint condition, in particular to a variational assimilation method for a typhoon under a dynamic balance constraint based on a WRF model, and belongs to the field of atmospheric science research. Background technique [0002] Typhoons are severe disastrous weather systems in the tropics, which bring huge losses to coastal areas every year. Therefore, improving the accuracy of typhoon forecast is related to life and social safety. As an important means of weather forecasting today, numerical models can objectively predict the track and intensity of typhoons. Since atmospheric numerical forecasting is an initial value problem, it is not only required that the model can accurately reflect the evolution law of the weather process, but also that the initial atmospheric state is accurate. [0003] For improving the initial field of the model, data assimilation is...

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Problems solved by technology

However, due to the lack of dynamic constraints of the numerical model, the defect of the 3DVAR method is that the adjustment of indirect observations during the assimilation process is often unreasonable, and it is easy to cause the imbalance of the atmospheric state quantities in the assimilation analysis field, such as the structural configuration of the pressure field and the wind field. Satisfy the physical balance relationship

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