Predictability of the Warm Core Eddy-Loop Current Separation in the Gulf of Mexico

A regional Relocatable Navy Coastal Ocean Model (RELO NCOM) for the Gulf of Mexico has been used to examine the 30-60 days predictability of the Warm Core Eddy (WCE) separation from the Loop Current (LC) with a particular reference to the 2010 Deepwater Horizon oil spill period. For the 60-day forecasts, the NOGAPS surface forcing is reverted to a three-hourly climatology after 5-day analysis quality forcing fields with each simulation initialized from the data assimilative run. Three, 60-day forecasts are carried out for the period February to October 2010 representing prior to, during, and after the LC-WCE separation. Results from these numerical experiments are compared with the data constrained assimilative run. It is found that the structure of the LC prior to and after the LC-WCE separation during the 60-day forecast compares well with the assimilative run and satellite derived sea surface height observations, however, the model shows limited predictability of the LC-WCE separation. When we repeated the 60-day forecasts for a different time period of October-November 2011, the predictability of the LC-WCE separation is greatly improved. These numerical experiments suggest that the predictability of the LC-WCE separation depends on the various factors, including the strength of LC, WCE being reattaching to the LC before remaining fully detached and the dynamical flow instabilities.