Development of an advanced aviation nowcasting system in support of air traffic management by blending radar nowcasting data with NWP forecasts

Intense convective weather could have adverse effects on flight safety and airport ground operations. To assist Air Traffic Management (ATM) to better manage the flight traffic over the Hong Kong Flight Information Region (FIR), the Aviation Thunderstorm Nowcasting System (ATNS) has been developed by the Hong Kong Observatory (HKO) to predict the movement of thunderstorms near the Hong Kong International Airport (HKIA) and its neighbouring airspace in the next hour. ATNS is an automatic tracking and prediction system for future movement of thunderstorms based on radar reflectivity data, using artificial intelligence and a sophisticated extrapolation method. Case studies demonstrate that the performance of ATNS is comparable with and sometimes even better than the other state-of-the-art nowcasting systems, such as TITAN. A prototype of ATNS has been provided to local ATM users for evaluation.

Due to the limitation of the extrapolation technique, ATNS can only provide reliable forecasts up to one to two hours ahead. In order to extend the forecast period and to capture the evolution of thunderstorms, the blending of the radar-based nowcasting data with the forecasts from a rapidly updated Numerical Weather Prediction (NWP) model has also been explored by HKO so that the thunderstorm forecasts could be usable up to 6 hours ahead. The NWP model under testing is a high-resolution (horizontal resolution of 5 km), non-hydrostatic model. The blended nowcast-NWP system is named Advanced Aviation Nowcasting System (AANS). Case studies indicate that AANS could improve the forecasts at T+1 hour and beyond. This paper presents the concept of AANS under development and provides some preliminary performance results.