Application of Ensemble-Based Sensitivity Analysis During SHOUT

Tropical Cyclones (TCs) predominantly occur over the ocean; therefore, there are often few in situ observations available for data assimilation near TCs, which could benefit subsequent track and intensity forecasts.   One potential method to collect additional in situ data near TCs is to deploy aircraft that fly around these systems; however, these flights are resource-intensive and require planning; therefore, it is of interest to determine the optimal locations to take observations that will have the largest impact on the subsequent forecast.  Ensemble-based methods provide a natural way to estimate target observation locations because it combines both sensitivity analysis with data assimilation and has shown promise for TC applications using retrospective data.  During the 2016 Sensing Hazards with Operational Unmanned Technology (SHOUT) campaign, ensemble-based target locations were computed from an 80-member Hurricane Weather Research and Forecasting (HWRF) model and the 51-member European Center for Medium Range Weather Forecasting (ECMWF) ensemble prediction system and used to design flight patterns for the NASA Global Hawk.  This talk will provide a summary of the ensemble-based targeting algorithm and how the output was used in SHOUT operations planning.  Illustrative case studies will be shown, including comparisons between HWRF and ECMWF-based targeting guidance.