The Front Cover
One of today’s hot topics in energy policy and its economics is the reduction of uncertainties in wind resource assessment and forecasting. The article on page 7 provides details of the state of the art for wind tunnel modelling for atmospheric flow over topography. The image on the cover shows Laser–Doppler anemometry used for non-intrusive flow measurements. Two beams are made to intersect at their waists (focal points). Hazer particles pass through the fringes. Doppler equivalent frequency-shift of the scattered light is measured and the velocity of the fluid can be calculated.