the technique of variational data assimilation has been considered as an effective method in the aspect of improving the quality of the initial fields of numerical weather predication ( nwp ) . however, it does make strong demands on mathematical property of the cost function, in the meantime, it needs higher demand by using local optimization method and depends on the computer resource 变分同化技术被公认为是提高数值模式初始场质量的有效方法之一,但它对目标函数的数学性态有较高的要求,同时,目前的四维变分同化技术在业务中要求有较高的环境才能实现。