Atmospheric science is the study of the atmosphere—the blanket of air covering the Earth. Atmospheric scientists study the atmosphere's physical characteristics, motions, and processes, and the way in which these factors affect the rest of our environment. The best-known application of this knowledge is forecasting the weather. In addition to predicting the weather, atmospheric scientists attempt to identify and interpret climate trends, understand past weather, and analyze current weather. Weather information and atmospheric research are also applied in air-pollution control, agriculture, forestry, air and sea transportation, defense, and the study of possible trends in the Earth's climate, such as global warming, droughts, and ozone depletion.

Atmospheric scientists who forecast the weather are known as operational meteorologists; they are the largest group of specialists. These scientists study the Earth's air pressure, temperature, humidity, and wind velocity, and they apply physical and mathematical relationships to make short-range and long-range weather forecasts. Their data come from weather satellites, radars, sensors, and stations in many parts of the world. Meteorologists use sophisticated computer models of the world's atmosphere to make long-term, short-term, and local-area forecasts. More accurate instruments for measuring and observing weather conditions, as well as high-speed computers to process and analyze weather data, have revolutionized weather forecasting. Using satellite data, climate theory, and sophisticated computer models of the world's atmosphere, meteorologists can more effectively interpret the results of these models to make local-area weather predictions. These forecasts inform not only the general public, but also those who need accurate weather information for economic and safety reasons, such as the shipping, air transportation, agriculture, fishing, forestry, and utilities industries.

Meteorologists use data collected from sophisticated technologies like atmospheric satellite monitoring equipment and ground-based radar systems. Doppler radar, for example, can detect airflow patterns in violent storm systems, allowing forecasters to better predict thunderstorms, flash floods, tornadoes, and other hazardous winds, and to monitor the direction and intensity of storms. They also monitor surface weather stations and launch weather balloons, which carry equipment that measures wind, temperature, and humidity in the upper atmosphere.

While meteorologists study and forecast weather patterns in the short term, climatologists study seasonal variations in weather over months, years, or even centuries. They may collect, analyze, and interpret past records of wind, rainfall, sunshine, and temperature in specific areas or regions. Some look at patterns in weather over past years to determine, for example, whether a coming season will be colder or warmer than usual. Their studies are used to design buildings, plan heating and cooling systems, and aid in effective land use and agricultural production.

Some atmospheric scientists work exclusively in research. Physical meteorologists, for example, study the atmosphere's chemical and physical properties; the transmission of light, sound, and radio waves; and the transfer of energy in the atmosphere. They also study other atmospheric phenomena, such as the factors affecting the formation of clouds, rain, and snow; the dispersal of air pollutants over urban areas; and the mechanics of severe storms. Environmental problems, such as pollution and shortages of fresh water, have widened the scope of the meteorological profession. Environmental meteorologists study these problems and may evaluate and report on air quality for environmental impact statements. Other research meteorologists examine the most effective ways to control or diminish air pollution.

Work environment. Weather stations are found everywhere—at airports, in or near cities, and in isolated and remote areas. In addition to analyzing information in offices, some atmospheric scientists also spend time observing weather conditions on the ground or from aircraft. Weather forecasters who work for radio or television stations broadcast their reports from station studios, and may work evenings and weekends. Meteorologists in smaller weather offices often work alone; in larger ones, they work as part of a team. Those who work for private consulting firms or for companies analyzing and monitoring emissions to improve air quality usually work with other scientists or engineers; fieldwork and travel may be common for these workers.

Most weather stations operate around the clock, 7 days a week, as weather conditions can change rapidly and timely information is essential, particularly during periods of severe weather. As a result, jobs in such facilities involve night, weekend, and holiday work, often with rotating shifts. During weather emergencies, such as hurricanes, meteorologists may work extended hours. Operational meteorologists also are often under pressure to meet forecast deadlines. Meteorologists and research scientists who are not involved in forecasting tasks work regular hours, usually in offices.