Real-Time GNSS Meteorology in Europe - Hurricane Lorenzo Case Study.

Near real-time estimation of zenith total delays (ZTD) of Global Navigation Satellite Systems (GNSS) signals is operationally performed in Europe. We demonstrate that high accuracy ZTD can be provided even in real-time. Using a state-of-the-art processing strategy we estimate ZTD and horizontal gradients for 162 permanent stations in Europe over 100 days in 2019, covering the event of hurricane Lorenzo. The accuracy of real-time ZTD with respect to the final ZTD product varies from 3.3 to 10.4 mm. The accuracy of real-time ZTD with respect to the ICON numerical weather prediction model varies from 4 mm to 18 mm and we notice station-specific biases, reaching up to ±10 mm. We demonstrate that horizontal gradients show signatures under the severe weather during hurricane Lorenzo in 2019.