Assimilation Definition

Data assimilation merges many different observations together with an estimate of the climate provided by a model of the climate system. The model is a crucial part of the process of data assimilation because it provides us, at any one time, with a complete picture of the climate based on our current understanding of how the climate operates. The model provides the physical laws as we know them, to fill in the gaps where we have no observations, provides estimates of quantities we do not observe, and improves the accuracy of our final estimates of the climate.

The image on the lower right illustrates two states within the assimilation process. The observations are represented by the small colored squares. The analysis is the contoured color in the background.