气象学报2012，Vol.70Issue(1)：109-118,10.
数字滤波初始化(DFI)在高水平分辨率模式中的应用
Difficulties in the implementation of the digital filter initialization in a high resolution numerical weather forecast model
摘要
Abstract
The rationale to use the digital filter initialization (DFI) relies on the assumption that the fastest unbalanced inertial gravity waves propagate quasi-linearly within the balanced background flow and consequently can simply be filtered as long as there is no overlap with the meteorologically significant part of the spectral frequencies. For the numerical forecast with higher horizontal resolution, the inertial gravity waves with shorter wave length and higher frequency can be resolved by the numerical model. Therefore, its difficult to identify the fake high-frequency oscillations from the meso-scale weather signals. In this context , the performance of the DFI for high-resolution forecasts has been at stake for both the research and operational implementation. In this paper, a preliminary investigation into the noise control and initialization for high resolution forecasts are conducted. It's revealed that even for a 'noise-free' forecast, the weather-related information displays a large and unreasonable surface pressure tendency, the same as the fake high frequency oscillation. A challenging issue is the introduction by the 3DVAR of high-frequency fake oscillations. Although the DFI is an efficient noise controlling approach, it is found to be impossible to remove the fake oscillaiton introduced by the 3DVAR while ensuring the meteorologically significant signals be kept in the initial conditions. An ideal noise controlling effect can be reached by extending filtering windows with cost of more additional computation time and the possible damage to weather-related signals. Therefore, compromise should be made between the acceptable filtering effect and forecast quality when implementing DFI. Finally, some suggestions relating to the implementation of the DFI in limited-area high resolution numerical forecasts are given.关键词
数字滤波初始化/分辨率/惯性重力波Key words
Digital Filter Initialization/Resolution/Inertial-gravity wave分类
天文与地球科学引用本文复制引用
陈敏,Huang Xiangyu,Wang Wei..数字滤波初始化(DFI)在高水平分辨率模式中的应用[J].气象学报,2012,70(1):109-118,10.基金项目
国家自然科学基金项目(40505020)和公益性行业(气象)科研专项(GYHY200706004、GYHY200706042). （40505020）
