Atmospheric science studies the conditions and variations of the atmosphere and the interactions with other systems. The goals are to understand atmospheric dynamical (fronts, cyclones, waves, circulations, etc.), physical (radiation, clouds and precipitation, planetary boundary-layer turbulence, etc.), and chemical (acid rain, ozone, aerosols, etc.) phenomena and processes, and the interactions through energy, water, momentum, and trace gas/particle exchanges with ocean, land, vegetation and ice. The objectives are to develop and improve skills for weather and climate predictions and provide information for impact assessment. Atmospheric research is conducted based on meteorological observations, physical foundations (especially fluid dynamics), and chemical theory. According to time scales of atmospheric processes, atmospheric science is traditionally categorized into meteorology and climatology. Meteorology studies short term processes ranging from hours to years, while climatology understands the average properties of those processes over long periods and their changes.
The interaction between the atmosphere and forests as well as other ecosystems is one of the research areas in atmospheric science. The atmosphere supplies energy, water, and nutrients, which is an important environmental factor determining the structure, function, and disturbances of ecosystems. Meanwhile, changes in ecosystems can impact evapotranspiration, ground radiation balance, and turbulent activities by modifying leaf area and stomatal resistance, albedo, and roughness, respectively. This will further change air humidity, temperature, winds, and precipitation.