The Southern Ontario LIDar (SOLID) Mesonet: Impacts on Aviation and Severe Weather Nowcasting

There exists a demonstrated need for enhanced measurements of vertically-resolved meteorological parameters for nowcasting and to evaluate and enhance the performance of numerical weather prediction (NWP) systems. This is particularly true in urban areas where there exists a lack of upper air observations. To address this need, Environment and Climate Change Canada (ECCC) established the Southern Ontario Lidar (SOLID) Mesonet in and around Toronto. Seven Doppler lidars and one water vapour Differential Absorption Lidar (DIAL) provide real-time observations of aerosol backscatter, cloud base height, vertical wind and water vapour profiles, and the planetary boundary layer (PBL) height to aviation and operational weather forecasters. SOLID is designed to complement an adjacent profiling Mesonet, The New York State Mesonet. These two Mesonets are a primary source of upper air observations for the mixed rural / urban region they encompass, inhabited by 26+ million people.

As part of an ongoing impact analysis, this project will assess the potential of these profiling instruments to improve nowcasting and data assimilation efforts. A multi-year evaluation of Doppler wind lidars demonstrated excellent performance with small averaged differences (< 0.27 m/s) to co-located radiosondes. Several case studies demonstrate the impact of the Mesonet’s observations, particularly for aviation nowcasting and severe weather (e.g., convective initiation). In one case, a passing cold front resulted in a sudden and extreme wind shift of ~180^o within 10 min, affecting aviation operations at the Toronto Pearson Airport. It is envisioned that the improvement in knowledge of the state of the PBL will improve forecasters’ situational awareness, provide near real-time analysis for automated nowcasting systems, and enable more in-depth verification of NWP forecasts.