A part of meteorology that deals with observations and processes in the smallest scales of time and space, approximately smaller than 1 km and less than a day (i.e., local processes). Micrometeorological processes are limited to shallow layers of frictional influence (slightly larger-scale phenomena like convective thermals are not part of micrometeorology). Therefore, the subject of micrometeorology is the bottom of the atmospheric boundary layer; namely, the surface layer. Exchange processes of energy, gases, etc., between the atmosphere and the surface (water, land, plants) are important topics. Therefore, micrometeorology is closely connected with most of the human activities in the atmosphere. Microclimatology describes time-averaged (long-term) micrometeorological processes, and micrometeorologists are interested in the fluctuations of these.