Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However. in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error is measured by collocating a meteorological mast and a lidar at two Greek sites. https://chefesquipmenters.shop/product-category/microwaves/