The impact of lakes on the European climate as simulated by a regional climate model

The impact of lakes on the European climate is considered by analysing two 30-year regional climate model (RCM) simulations. The RCM applied is the Rossby Centre regional climate model RCA3.5. A simulation where all lakes in the model domain are replaced by land surface is compared with a simulation where the effect of lakes is accounted for through the use of the lake model FLake coupled to RCA. The difference in 2m open-land air temperature between the two simulations shows that lakes induce a warming on the European climate for all seasons. The greatest impact is seen during autumn and winter over southern Finland and western Russia where the warming exceeds 1 °C. Locally, e.g. over southern Finland and over Lake Ladoga, the convective precipitation is enhanced by 20%―40% during late summer and early autumn while it is reduced by more than 70% over Lake Ladoga during early summer.