The lidar technique allows wind and temperature measurements in the whole middle atmosphere with high vertical and temporal resolution. The wind retrieval relies on measuring the tiny Doppler shift of light that is backscattered by moving air particles. This thesis introduces in detail the wind retrieval method and its validation, and presents wind results from the winter seasons of the years 2009 to 2012 at an Arctic site. Winds and temperatures reveal large variability, from year to year and within single months. On short time scales winds and temperatures are disturbed by gravity waves.