The increasing use of wind turbines as a renewable energy technology requires a greater understanding of the potential effects its deployment could have on large scale flow patterns. As wind turbines capture energy and interrupt the flow, they introduce downstream effects, which can impact climate patterns and storm tracks. It has previously been shown that large-scale wind farms have an appreciable effect on regional temperature and wind patterns (Keith, 2004). In that study, surface roughness was held fixed in time. Here, we use NCAR's Community Atmosphere Model to investigate how a change in surface roughness affects downstream storm paths. This change can be accomplished in the field through an adjustment of the attitude of turbine blades with respect to the wind.

We investigate the strength and direction of storm trajectories on the eastern coast of the United States as well as farther downstream in Europe. We hope to determine whether deliberate manipulation of the effective roughness length of a wind farm produces predictable downstream effects. Hoffman (2002) suggested that large wind farms might be part of a strategy for controlling global weather. In this forward-modeling experiment, we test the limits of the downstream control exerted by wind farm management.