An Observing System Simulation Experiment for the Unmanned Aircraft System data impact on tropical cyclone track forecasts
High-altitude, long-endurance Unmanned Aircraft Systems (HALE UAS) are capable of extended flights for atmospheric sampling. A case study was conducted to evaluate the potential impact of dropwindsonde observations from HALE UAS on tropical cyclone track prediction; tropical cyclone intensity was not addressed. This study employs a global observing system simulation experiment (OSSE) developed at the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA ESRL) that is based on the NOAA National Centers for Environmental Prediction
Gridpoint Statistical Interpolation (GSI) data assimilation system and Global Forecast System (GFS) forecast model. Different strategies for dropwindsonde deployment and UAS flight paths were compared. The introduction of UAS-deployed dropwindsondes was found to consistently improve the track forecast skill during the early forecast up to 96 hours, with the caveat that the experiments omitted both vortex relocation and dropwindsondes from manned
flights in the tropical cyclone region. The more effective UAS dropwindsonde deployment patterns sampled both the environment and the body of the tropical cyclone.