论文标题

数据同化:基于初始条件依赖性的两个不同的观点

Data Assimilation: Two Different Perspectives Based on the Initial-Condition Dependence

论文作者

Murshed, Mohammad N., Subah, Zarin, Uddin, M. Monir

论文摘要

数据同化(DA)是一种计算工具,它使用模型中的值和实际测量值来达到最佳可接受的值。相反,这种技术依赖于卡尔曼获得的想法。我们指出,DA根据问题的类型具有两种不同的观点。在本文中,我们研究了两种问题类型:一种不依赖初始条件,另一个依赖于初始条件。数据同化在两个示例中得到了证明:达卡市的径流监测和预测(初始条件独立)和大气中的对流(初始条件取决于)。我们表明,当问题具有初始条件依赖性时,标准DA在没有初始条件依赖性的问题上效果很好,而分段DA则可以使用。在第一个示例中,我们利用了标准数据同化,以达到比模型和观测值的值更现实的值。第二个示例是我们设计了一种方法,以分段方式在数据同化框架中找到系统的动力学,并注意到数据同化的动态(即使是由于嘈杂的初始条件也是由于嘈杂的初始条件)与真实的动力学非常吻合。

Data Assimilation (DA) is a computational tool that uses value from the model and the real measurement to arrive to an optimally acceptable value. Rather, this technique relies on the idea of Kalman gain. We point out that DA has two different perspectives based on the type of problem. In this paper, we look into two problem types: one that does not rely on the initial condition, and the other that is initial condition dependent. Data Assimilation is demonstrated on two examples: runoff monitoring and forecasting in the city of Dhaka (initial condition independent) and convection in the atmosphere (initial condition dependent). We show that standard DA works well for problems with no initial condition dependence and piecewise DA is to be utilized when the problem has initial condition dependence. In the first example, we exploited standard Data Assimilation to arrive at values that are more realistic than the ones from the model and the observations. The second example is where we devised a method to find the dynamics of the system in a piecewise manner in Data Assimilation framework and noticed that the data assimilated dynamics (even due to noisy initial condition) is in good agreement with the true dynamics for a reasonable extent of time in future.

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