GRAPES业务全球集合控制预报初值的动力升尺度方法

Dynamical Upscaling Technique for Initial Fields of GRAPES Operational Global Ensemble Control Forecast

以生成GRAPES全球集合预报业务系统的控制预报初值为目的,基于GRAPES全球模式,开展了控制预报初值生成方法研究,发展了高分辨率初值动力升尺度方法,并检验了不同方法的可行性。通过对比不同方法产生的初始场形态,证实了仅仅对高分辨率初始场进行二维水平插值存在不足,基于静力学方程对Exner气压变量进行三维插值至关重要。结果表明,动力升尺度方法利用静力平衡关系,对全场的温压场进行调整,使之协调平衡,可以改善二维水平插值方法导致的初始位势高度场和温度场的噪音问题,产生适用于GRAPES全球集合预报业务系统的控制预报初值。

Aiming to generate the initial fields for the control forecast of the GRAPES global ensemble prediction system,based on the Global/Regional Assimilation and Prediction System（GRAPES）global model,the initial field generation scheme is studied,and a dynamical upscaling technique of the high resolution initial field is developed,and the feasibility of different schemes is verified.By comparing the spatial patterns of the initial fields obtained through different schemes,it is verified that the horizontal interpolation scheme has certain shortcomings,and the three-dimensional interpolation for the Exner pressure variable based on the hydrostatic equation is of great importance.The results show that with the dynamical upscaling technique,the initial geopotential height and temperature noise problems due to the horizontal interpolation scheme can be improved by adjusting the global temperature and pressure fields,so that they are balanced according to the hydrostatic balance relation,and the initial field of low resolution obtained with the dynamical upscaling technique is suitable for the control forecast of the operational GRAPES global ensemble prediction system.