OSSE Evaluation of the Impact of Global Hawk Dropsonde Spatial Distribution on Vortex-Scale Tropical Cyclone Analyses and Forecasts

The Global Hawk unmanned aircraft system (UAS) has the unique capability of sampling tropical cyclones from a high altitude for a length of time that exceeds the capabilities of existing manned reconnaissance aircraft. In addition to a variety of remote sensing instruments, the Global Hawk’s research payload includes up to 88 dropsondes. The goal of this study is to evaluate how targeting different areas of a tropical cyclone with Global Hawk dropsondes affects vortex-scale analyses and forecasts, with possible implications for future flight planning. Results will be presented from an observing system simulation experiment (OSSE) with dropsonde observations simulated from the Nolan et al. (2013) hurricane nature run and assimilated into NOAA's HWRF model using NOAA/AOML/HRD’s Hurricane Ensemble Data Assimilation System (HEDAS) for multiple cases as the simulated storm intensifies from tropical storm to major hurricane.