Is winter precipitation change over Europe underestimated in current climate projections?

Model output, observational data, and scripts corresponding to the manuscript "Is winter precipitation change over Europe underestimated in current climate projections?" <strong>Abstract</strong> IPCC models project a likely increase in winter precipitation over northern Europe under a high-emission scenario. These projections, however, typically rely on relatively coarse ~100-km-resolution models that might misrepresent important processes driving precipitation, such as extratropical cyclone activity. Here, we show that a pioneering 50-km-atmosphere–1/12°-ocean global coupled model simulation projects a substantially larger increase in winter precipitation over northwestern Europe by mid-century than lower-resolution configurations. For this increase, both the highest ocean and atmosphere resolutions are essential: First, only the eddy-rich (1/12°) ocean projects a progressive northward shift and warming of the Gulf Stream. Second, only the 50-km atmosphere translates such warming into strengthened North Atlantic extratropical cyclone activity through enhanced diabatic heating and eddy-driven jet. Our results suggest that climate projections using traditional ~100-km-resolution models might underestimate the precipitation increase over Europe in winter and, consequently, the related potential risks.