ABSTRACT
This chapter aims to introduce this important layer, the actual devices available for the measurements with their advantages and disadvantages, and presents some results for the field measurements in Amazonia. The atmospheric boundary layer (ABL) is the lower part of the troposphere and from the meteorological point of view it plays an important role connecting the surface with the free atmosphere. The ABL plays an important role in meteorology, including studies of air pollution dispersion and aeronautical and aviation procedures regarding aircraft landing and takeoff. Also, the characteristics and behavior of the ABL by its turbulent exchange processes is very important and crucial in determining the local weather. The ABL can be studied by three different approaches: by measurements, by numerical modeling, and by simulations using wind tunnel. The direct measurements of the ABL can be classified as surface in situ measurements made by masts or towers, balloon-borne measurements made by rawinsoundings, and/or tethered balloons.
