Meteorologists who forecast the weather, known professionally as operational meteorologists, are the largest group of specialists. Their data come from weather satellites, weather radar, and remote sensors and observers in many parts of the world. These forecasts inform not only the general public, but also those who need accurate weather information for both economic and safety reasons, as in the shipping, aviation, agriculture, fishing, and utilities industries. The use of weather balloons, launched twice a day, to measure wind, temperature, and humidity in the upper atmosphere, is being supplemented by more sophisticated weather equipment which transmits data as frequently as every few minutes. Doppler radar, for example, can detect rotational patterns in violent storm systems, allowing forecasters to better predict thunderstorms, tornadoes, flash floods, as well as their direction and intensity.
Some meteorologists engage in research.
They also study factors affecting formation of clouds, rain, snow, and other weather phenomena, such as severe storms. Climatologists collect, analyze, and interpret past records of wind, rainfall, sunshine, and temperature in specific areas or regions. Their studies are used to design buildings and to plan heating and cooling systems, effective land use, and agricultural production. Other research meteorologists may examine the most effective ways to control or diminish air pollution or improve weather forecasting using mathematical models. Meteorologists involved in weather forecasting sometimes work evenings, weekends, or holidays.