Regardless of the location meteorologists are predicting the weather for, they need to know what is happening in other parts of the world in order to make accurate forecasts. For example, it is helpful in predicting weather in California to know current weather conditions across the Pacific in, perhaps, North and South Korea. And to forecast the weather three days ahead, meteorologists need to know the weather in Antarctica, the nations south of the Equator and other parts of the world.
Weather-Information Tools
What kind of information do weather forecasters rely on? A typical national weather-forecasting center may draw on data from about 10,000 ships and 30,000 airplanes because during their travels, some of their instruments record data useful to meteorologists.
Satellites are also vital in weather forecasts. In the United States, the federal government uses two kinds of weather satellites. From about 22,400 miles above the earth, geostationary satellites record information about the Western Hemisphere all day, every day. And from about 540 miles above the earth, polar-orbiting satellites circle the globe to record global weather information.
The weather-prediction process also uses small devices called sondes. More specifically, a dropsonde is attached to a parachute and dropped from a plane. A radiosonde is attached to a weather balloon and may reach heights of 115,000 feet or more before descending. As the dropsonde drops and the radiosonde ascends, they record humidity, temperature and pressure.
About 7,000 ocean buoys, some fixed and some free to drift, deliver data for forecasting too. So do about 40,000 fixed weather stations on land. Piloted balloons send about 700 weather reports daily. And about 600 daily recordings of wind speed and direction come from wind profilers, which are a type of Doppler radar.
Doppler Radar
Whether the forecaster uses relatively few resources in predicting the weather or many highly sophisticated ones, all forecasts make use of weather radar, specifically Doppler radar. Doppler radar works by transmitting microwave signals into the air where they hit raindrops, snowflakes, hail and other objects. These signals then bounce back to the radar’s receiver that collects them. Next, the signals arrive at the antennae from where they are sent for processing so that meteorologists and people interested in the weather can use the data.
Weather-Forecasting Models
Because of the staggering amount of data necessary to predict the weather, professionals predicting weather for nations, continents and global organizations now rely heavily on supercomputers to do the mathematical calculations. After the computers have done their work, visual representation of the weather, also called (weather) models, are produced.
