Abstract

At the UK Met Office we have recently run climate simulations at km-scale over the UK, Europe, Africa and South America. This includes the first continuous 100-year ensemble projections at 2.2km resolution over the UK (an extension of ‘UKCP Local’), and ongoing 4.5km ensemble projections over Africa. In this talk I will highlight new understanding of changes in high impact events from these simulations. This includes changes in intense organised convective storms, lighting, hail and sting jets. Using the new 100yr UKCP Local projections, I will explore the emerging signal of changes in hourly precipitation extremes through time. This provides evidence that changes in extremes will manifest, not as a smooth trend, but as periods of rapid change followed by pauses. We also explore drivers of changes in severe storms, and the extent to which impact-relevant changes in storms may be represented differently using pseudo-global warming approaches compared to full global climate model downscaled simulations. This has implications for the design of convection-permitting ensemble projections in the future. Finally I will discuss next steps for km-scale climate modelling at the UK Met Office and collaborations to exploit the new simulations in downstream impacts modelling.