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In the wake of budget cuts by the Trump administration, a Silicon Valley startup will soon start to replace the National Oceanic and Atmospheric Administration’s (NOAA’s) weather balloons with AI-powered alternatives, which are supposed to be much cheaper.
Since March, NOAA has slashed its weather balloon launches across the United States after the Department of Government Efficiency (DOGE) cut the government agency’s budget by 25%. This led to hundreds of layoffs or voluntary resignations, resulting in fewer balloon launches by NOAA.
Weather agencies across the world use weather balloons to make upper air observations that are crucial for forecasts. Upper air refers to the Earth’s atmosphere above about 5,000 feet, and it is from here that the planet gets its rain and drought, wind and calm, and heat and cold at the surface.
The India Meteorological Department (IMD) also uses weather balloons to measure meteorological variables.
Centuries-old tradition
The tradition of making upper air observations goes back to the 18th Century. It all began in 1749 when two students in Glasgow, Scotland, used kites to measure the temperature at high altitudes. Subsequently, meteorologists started to send kites in the upper atmosphere carrying aloft instruments — called meteorographs — that measured pressure, temperature, and relative humidity data.
In the meantime, hot balloons were invented in France in the 1780s. Scientists would travel to high altitudes in these balloons, taking with them barometers, thermometers, and other instrumentation for measurements and experiments.
However, in the early years, manned flights proved to be quite dangerous. For instance, in 1862, two men in Great Britain went to an altitude of about 11 km, and nearly died from the extreme cold and lack of air.
Therefore, meteorologists kept using kites to make upper air observations despite their several drawbacks. For example, kites could not reach above the altitude of 3 km or around 9,800 feet, and data could not be evaluated until after the kite was reeled in and the meteorograph recovered.
By 1899, the US Weather Bureau had 17 kite stations, each of which regularly lifted instruments to 8,000 feet using a train of several kites joined together.
Advent of weather balloons
French meteorologist Leon Teisserenc de Bort was among the first to use weather balloons. He is known to have launched hundreds of these balloons as early as 1896, discovering the tropopause and stratosphere.
This allowed meteorologists to make observations at a height that they could not reach before. The weather balloon carrying the meteorograph would burst upon reaching a certain altitude, and the instrument would return gently to Earth, preserving the data until it was recovered.
However, there were still some challenges. For instance, the data recorded by meteorographs would not be readily available for weather forecasting. There was also a chance of losing the data if the meteorograph could not be recovered.
These issues were tackled with the invention of radiosondes, or radio-meteorographs, in the early 1930s. The instrument, smaller than the size of a coffee cup, was not only able to measure meteorological variables in the atmosphere but also transmitted the data back to the ground station.
In 1937, the US Weather Bureau established a network of radiosonde stations that has continued to the present day. India also has a similar network with 56 radiosonde stations across the country.
Over the years, radiosondes have gone through several improvements. They are now much lighter, have a longer battery life, and even employ techniques such as global positioning system (GPS) for more accurate position tracking and wind measurements.
But the method of sending them to the upper atmosphere has remained the same, via weather balloons.
Enduring significance
Currently, twice a day, about 900 weather stations around the world launch weather balloons in a coordinated international programme to measure conditions in the upper atmosphere. The launch takes place at 0000 UTC (Coordinated Universal Time) and 1200 UTC. This corresponds to 5.30 AM and 5.30 PM Indian Standard Time (IST).
The balloons are launched at the same time so that meteorologists can create a comprehensive picture of atmospheric conditions, which is essential for accurate weather forecasting.
Typically, today’s weather balloons, made of latex and filled with helium, can reach an altitude of 1,15,000 feet (35 km) in a journey lasting up to two hours. The radiosonde is suspended 66 feet below the balloon.
All radiosonde measurements can be accessed worldwide from a central database by researchers. That data help research climate change, El Niño cycles and other weather patterns.
Notably, weather balloons continue to hold importance in an era of satellites for several reasons. For instance, while satellites are good at giving a big picture and ground measurements, weather balloons help provide information about the key middle part of the forecasting puzzle — the atmosphere, where most of the weather phenomena take place.
These balloons get “the detailed lower atmospheric level of temperature and humidity that can determine whether the atmosphere is going to be hot enough to set off severe storms and how intense they might be,” Director Elbert “Joe”, former US National Weather Service, told EuroNews.
Also, radiosonde data plays a key role in calibrating derived satellite data to ensure that what the satellite is seeing is recorded correctly.
That is why NOAA’s slashing of its weather balloon launches has made experts across the world concerned. They believe the move will severely impact weather forecasts.
When Russia tried to cut its radiosonde launches in half, between January 2015 and April 2015, European forecasters saw a decline in their model’s forecast quality, according to a report by American Meteorological Society.
