Weather balloon

A weather balloon, also known as a sounding balloon, is a high-altitude balloon (HAB) that carries instruments into the stratosphere for measuring atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. First invented in the late 19th century, weather balloons have overgone several remodels and are still used by researchers across Europe, North America, and Asia to this day. The balloon itself is made of latex and filled with either helium or hydrogen to produce lift. Balloons can be tracked by radar, RDF, or GPS. Balloons meant to stay at a constant altitude for long periods are known as transosondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and the height of cloud layers. For such balloons, a theodolite or total station is used to track the balloon's azimuth and elevation, which are then converted to estimated wind speed and direction and/or cloud height, as applicable.

Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and computer models for weather forecasting. Between 900 and 1,300 locations around the globe do routine releases, typically two or four times daily. Other uses for weather balloons consist of supplements for satellite readings, support for rocket launches, and other miscellaneous recordings.

The effectiveness of weather balloons is limited by their lack of coverage in some countries, as well as other atmospheric and instrumental factors. Environmental concerns have been raised over the frequent use of weather balloons, as the United States releases around 76,600 balloons annually. Many of these balloons end up in the ocean, up to 300 balloons per week, polluting the water and endangering the surrounding marine life.