The ideas behind the First-Order Time extrapolation to the Observation (FOTO) have been around NCEP for some time, and its development capitalizes on the previous work of many collaborators. In this technique, a low order (first order in this case) approximation is applied to approximate the time evolution of the analysis variables over the analysis interval. This technique is an attempt to better represent the time variability of the atmosphere within the Gridpoint Statistical Interpolation (GSI) analysis interval without substantially increasing the cost.

The presentation will outline the basic idea and the theoretical background of the FOTO method and summarize some of the results achieved in the development stage. These results will include the effects of FOTO on fitting various types of observations in the GSI global analysis, and a preliminary two-month global cycling experiment. Based on these results, it appears that the FOTO method has the potential of producing significant positive impact on GSI analyses and subsequent forecasts.