Quantifying real-time observations on model state estimation

Operational numerical weather or oceanographic prediction relies upon real-time observations combined with advanced data assimilation for the nowcast state estimation. Using advanced four-dimensional variational assimilation, it is possible to use the variational framework to quantify the impact of each individual observation upon the state estimate. Such methods help identify the observations that are redundant, most important, and even when potential instrument degradation begins. The Hawaiian Islands lie in the southern part of the North Pacific subtropical gyre impacting both the NE trade winds and the western flowing Northern Equatorial Current. Real-time observations are required to properly characterize the circulation. In this talk, I discuss the methods and results for quantifying the time-dependent impact of each observational platform (satellites and a variety of in situ) to various estimates of the oceanic circulation around Hawaii using a real-time forecast system.