四维变分同化中坐标轮转法的应用研究

Application of Coordinate Cycle to Four-Dimensional Variational Assimilation

探讨了下降算法的尺度化问题,试验发现尺度因子的选取对目标函数的收敛非常重要,而现有的计算尺度因子的方法并不能适用于所有的情况,因此提出将坐标轮转法应用于尺度化过程,对比试验表明了该方法有效,试验还发现将坐标轮转法和尺度化方法结合起来可以更好地提高试验效果。

In this paper, we discuss how to prosecute the scale of descent arithmetic. It is found from experiments that the choice of scale factor is very important to objective function＇s convergence. However, present methods used to compute the scale factor can ＇ t ensure a good result under all circumstances. We use the coordinate cycle method in the scale process, and the contrast experimental results testify its validity. Experiments also confirm that the joint use of the scale method and coordinate cycle method further improves on the the results of experiments.