The potential use of operational radar network data to evaluate the representation of convective storms in NWP models

• Published in: Quarterly journal of the Royal Meteorological Society Vol. 146; no. 730; pp. 2315 - 2331
• Main Authors: Stein, Thorwald H. M., Scovell, Robert W., Hanley, Kirsty E., Lean, Humphrey W., Marsden, Nicola H.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-07-2020; Wiley Subscription Services, Inc
• Subjects: Convection; Convective storms; Data; echo‐top height; Evaluation; Forecasting; model evaluation; Radar; Radar data; radar meteorology; Rain; Rainfall; Rainfall data; storm morphology; Storms; United Kingdom > UK
• ISSN: 0035-9009; 1477-870X
• DOI: 10.1002/qj.3793

Operational forecasting centres increasingly rely on convection‐permitting NWP simulations to assist in their forecasting of convective events. The evaluation of upgrades in the underlying NWP modelling system normally happens through routine verification using traditional metrics on two‐dimensional fields, such as gridded rainfall data. Object‐ and process‐based evaluation can identify specific physical mechanisms for model improvement, but such evaluation procedures normally require targeted and expensive field campaigns. Here, we explore the potential use of the UK operational radar network observations and its derived 3D composite product for evaluating the representation of convective storms in the Met Office Unified Model. A comparison of the 1 × 1 × 0.5 km 3D radar composites against observations made with the research‐grade radar at Chilbolton in the southern UK indicates that the 3D radar composite data can reliably be used to evaluate the morphology of convective storms. The 3D radar composite data are subsequently used to evaluate the development of convective storms in the Met Office Unified Model. Such analysis was previously unavailable due to a lack of 3D radar data of high temporal frequency. The operational nature of the UK radar data makes these 3D composites a valuable resource for future studies of the initiation, growth, development, and organisation of convective storms over the
UK.
Operational radar networks can be used to study the characteristics of convective storms, including their 3D morphology and development throughout the day. Two 3D composite radar products are verified against high‐resolution radar observations and are found to be reliable for analysis of storm structures using low reflectivity thresholds, but not for high thresholds associated with small‐scale features such as convective cores. The 3D composite data (Radar) shed new light on the development of convective storms in convection‐permitting NWP models (Model).