Modern Measurements

Since the late 20th century, technology has allowed meteorologists to develop and use automatic weather stations, which allow atmospheric conditions to be monitored without a meteorologist in the site.

This allows meteorologists to get a more accurate picture of the atmosphere, because meteorologists can get information from many locations at once.

Most automatic weather stations have a thermometer, barometer, hygrometer, and anerometer. Some automatic weather stations have a sensor that detects special weather conditions, such as fog.

Newer automatic weather stations run on batteries recharged by solar panels or wind turbines.

Many automatic weather stations, especially those at airports, include a transmissometer, a device that measures visibility.

One important group of automatic weather stations, the Automated Surface Observing System (ASOS), is used extensively by the National Weather Service for weather forecasting.

Temperature, pressure, humidity, wind speed, wind direction, and precipitation in the lower atmosphere give a great deal of information about weather conditions.

Meteorologists often measure high-altitude weather conditions by attaching instruments to unmanned helium or hydrogen weather ballons. The data is transmitted by radio to weather stations. Instruments that simultaneously measure and transmit meteorological data from ballons to weather stations below are radiosondes.

Measurements of high altitude conditions are also made by similiar instruments abroad sounding rockets. This instruments can be also helpful at studying auroras.

To measure the distance from the ground to the base of the cloud meteorologists use a ceilometer.