The effect of vertical wind profile on the energy yield of wind turbines is well known. This profile is usually defined by orography and the surface roughness of the surrounding area. The influence of thermal stratifications however, is not taken directly into account. This leads to the core question of this thesis: Does this non-observance provoke errors in the wind power calculation, especially in areas with distinct thermal stratifications such as the Marchfeld region? Therefore, two different methods for determining stratification were utilised for evaluation of four different seasonal LIDAR measurement periods. The assumption that thermal stratification could have such significant influence on the vertical wind profile, making an observation necessary was confirmed. Unfortunately, the applied methods to observe the stratification failed. The results of this thesis point out that an urgent need for new methods to observe stratification does exist.