Loop Current Operational Forecasting in 2015: Skill Assessment and Lessons Learned

摘要

2015 was a year of unprecedented Loop Current (LC) activity. From February to June 2015, the LC andrnits associated eddies were monitored at a significantly higher rate in southern Walker Ridge in support ofrncurrent-sensitive offshore operations. A privately operated ocean forecast system for the Northern Gulf ofrnMexico, a.k.a. the Eddy Forecast System (EFS), was actively employed as an integral part of the currentsrnmonitoring program. A total of 38 forecasts were performed with the EFS over this four-month period,rnmore than half of these were dedicated to support of operations in the southern Walker Ridge. In thisrnstudy, we evaluate the site specific EFS skill by comparing current speed forecasted at the site withrnobserved currents. Despite very complex LC-eddy configurations that presented a major challenge forrnforecasting and most demanding model skill definition, the EFS demonstrated skill up to 6 days onrnaverage for the entire four months period. The average site dependent skill was determined to vary fromrnabout 5 days to over 9 days, depending on the location relative to the LC and major eddies. Simplernensembling techniques, i.e. combining multiple forecasts, were shown to improve the EFS skill by 2-3rndays. Individual forecast failures over the same time period were also analyzed. An additional operationalrndata collection guided by "crucial uncertainties" identified by the EFS is proposed as an effective methodrnof reducing the number of failed forecasts and improving the overall model skill.