During May and June of 2006, the LTER CCE program launched a cruise off Point Conception closely following the California Cooperative Oceanic Fisheries Investigations (CalCOFI) line 80 and a valuable dataset was collected. These ocean variables include along-flow and cross-flow spatial gradients, vertical current shear, CTD and iron limitation.

Before the cruise was launched, a Regional Ocean Modeling System (ROMS) forecast, along with MODIS-Aqua imagery, were used to provide a “guide (for) the sequence of sites for experimental studies.” The ROMS forecast was released after a nonlinear forward run followed by applying a data assimilation technique using data from the CalCOFI cruise of previous month. Although the forecast of ocean states played a positive role, it had limitations in temporal and spatial resolution due to the nature of the data assimilation, which was optimal interpolation. In addition, the ROMS forecast has yet not been verified after validating data from the LTER CCE-P0605 cruise was collected.

Now a more sophisticated and advanced technique called the Incremental Strong Constraints 4-Dimensional Variational method (IS4DVAR) is being used to allow us to have higher resolution in both space and time. In this study, we generate the forecast of the ocean states for LTER CCE-P0605 cruise using ROMS IS4DVAR, verify its forecast skill, and discuss the way of using ROMS IS4DVAR for the next LTER CCE cruise.