SST Assimilation and Assessment of the Predicted Temperature from the GoMOOS Nowcast/Forecast System

A circulation nowcast/forecast system was developed for the Gulf of Maine as an integral component of the Gulf of Maine Ocean Observing System (GoMOOS) technical program. The system has been used to generate nowcasts and short-term forecasts of the circulation and physical properties in the Gulf of Maine. One of the expectations is that the model can provide consistent SST to fill in AVHRR gaps and eventually produce reliable 3D temperature fields for fishery applications. This paper first presents the framework of the nowcast/forecast system, which includes an algorithm to assimilate satellite derived SST. It then discusses the performance of the system be comparing the predicted and the observed temperatures (both in situ and satellite derived). In general, the assimilation algorithm is stable and produces SST patterns mimicking the AVHRR. However, the modeled temperature appears to be colder than the in situ temperature at buoy locations. Elimination of the exceptionally cold satellite SST at cloud edges before it is assimilated corrects for a large portion of the cold bias in the model. Furthermore, seasonal variation in temperature is well reproduced and the predicted synoptic temperature variation is significantly correlated with its counterpart from the mooring measured temperature.