| ABSTRACT | Convection-permitting atmospheric models have been shown to add value to coarser models with parametrized convection for the simulation of extreme precipitation, in particular for short-duration (i.e. sub-daily) extremes of a convective nature. Such events are the main cause of flash flooding, an acute risk in many coastal Mediterranean regions. The accurate simulation of short-duration rainfall events is thus key for the forecasting of flash-flooding and for predicting how the flash-flooding risk may change in the future. As such, evaluation of the realism of short-duration (extreme) precipitation in convection-permitting models is an important endeavour. Owing to a lack of observational datasets at both high spatial and temporal resolution, however, most evaluations of convection-permitting models have to date been at the hourly (or longer) temporal scale. The validation of precipitation in convection-permitting models at the sub-hourly scale has thus been identified as an important challenge for both weather forecasting and climate science (e.g. Chan et al., 2016).
Using a unique regional micro-gauge network from the Mediterranean city of Barcelona, with 5-minute precipitation observations spanning on average 20 years, we analyse the performance of the COSMO-CLM model at 0.02° (~2.2 km) resolution in simulating the characteristics – both mean and extreme – of observed precipitation during this period. Results indicate that the model simulates 5-minute and sub-hourly precipitation with comparable realism to that found at the hourly scale, suggesting that convection-permitting models can be a useful tool for the study of sub-hourly precipitation extremes in the Mediterranean region.
References:
Chan, SC, EJ Kendon, NM Roberts, HJ Fowler and S Blenkinsop (2016). The characteristics of summer sub-hourly rainfall over the southern UK in a high-resolution convective permitting model. Environmental Research Letters, 11(9), 094024. |