Earth’s atmosphere is about 97 kilometers (60 miles) high, not including the exosphere—the uppermost layer that some scientists consider more space-like than atmosphere-like. While 97 kilometers may not sound far, imagine trying to observe an event, such as a baseball game, from that distance. It is virtually impossible. Similarly, the distance from Earth’s surface to the upper levels of the atmosphere prevents scientists from discerning what happens there. Scientists require instruments far more accurate and discerning than the human senses to help bridge the distance between Earth’s surface and its atmosphere; this is where technology comes into play.

Observing the Atmosphere from Below

In the 1590s, Galileo Galilei invented one of the first pieces of technology ever used to observe properties of the atmosphere—the thermometer. Wanting to measure how hot or cold the air was in his native Italy, he designed a device made of glass with a hollow glass bulb at one end and a hollow, open tube at the other (think of the shape of a clock pendulum). Galileo held the bulb end in his hands, allowing it to heat up, then turned the contraption upside down, tube end first, into a water-filled basin. The water then rose into the contraption’s neck. How high it moved up or down depended on the temperature of the surrounding air, with colder air making the water rise higher into the glass. In 1612, another Italian scientist improved upon Galileo’s thermometer design by adding a number scale so that temperatures could be read.

Roughly 50 years after Galileo created the first thermometer, one of his apprentices, Evangelista Torricelli, created the barometer—an instrument that measures the air pressure. Today, barometers remain a vital tool for many scientists, including meteorologists, who use air pressure readings to determine whether the atmosphere is stable (under high air pressure) or stormy (influenced by low air pressure).

Observing the Atmosphere from Above

Thermometers, barometers, and other in-situ instruments—instruments that enable us to directly measure the air (“in situ” meaning “on site” or “in place” in Latin)—are essential to exploring the immediate atmosphere. But what if scientists want to explore how the atmosphere might act hours or days into the future, or in another part of the world? For this, scientists depend on remote-sensing instruments—tools that obtain information from some distance away.

The atmosphere’s subzero temperatures and thinning air have challenged scientists to develop technologies rugged enough to overcome these obstacles yet intricate enough to collect detailed observations while allowing the observer to keep both feet safely on the ground. One such instrument is the weather balloon. Weather balloons ascend to lofty heights with a package, known as a radiosonde, following close behind. As the radiosonde rises, its internal sensors measure characteristics such as temperature, pressure, and relative humidity, and a radio transmitter relays this data back to scientists every one to two seconds. Scientists then use this data (along with wind speed and wind-direction data, which are calculated by tracking the radiosonde’s position) to create weather forecasts and provide input for weather models.

A weather balloon can only travel about 32 kilometers (20 miles) up from the surface before the atmosphere’s ever-decreasing pressure causes the air pressure within the balloon to rise and the balloon’s skin to expand outward until it pops. To collect data at higher altitudes, scientists turn to satellites.

In the 1960s, NASA launched TIROS I, the nation’s first weather satellite. Today, weather satellites, which continuously circle our planet hundreds of kilometers above its surface, are one of the most effective tools for studying Earth. Similar to how standing on a mountain peak provides a bird’s-eye view of the surrounding landscape, satellites are able to “see” atmospheric events around the globe, including cloud cover, lightning-strike activity, wildfire-smoke plumes, volcanic-ash plumes, sea-surface temperatures, snow and ice cover, hurricane activity, and space disturbances, such as solar flares. Satellites also assist scientists in monitoring the atmosphere’s chemistry, such as ozone and air-pollution levels and greenhouse-gas concentrations. Not only do satellites collect data and relay it from space back to Earth’s surface, they also capture images of what they see.

Radar is another form of technology that captures images of the atmosphere. Unlike weather balloons and satellites, which scan the atmosphere from above, radar works by scanning it from ground-level. By observing how pulses of energy called radio waves interact with objects they meet in the air, scientists are able to detect the location of rain, snow, and other types of precipitation. Doppler radar allows scientists to not only detect a storm’s location, but its movement too. This is important for understanding whether a storm is approaching or moving out of a specific area and whether any rotation (a sign of possible tornadoes) exists in the atmosphere.

If you listen to weather forecasts on television, you have likely heard meteorologists mention a form of technology used to create your weather forecast: weather models. These models are essentially computer programs. Atmospheric data is fed into them so that they can “model” or simulate what the atmosphere’s conditions might be at some time in the future. The models do this by solving a group of mathematical equations (at speeds of quadrillions of calculations per second—weeks faster than can be done by hand), which govern how the atmosphere behaves in reality. In this way, the model is able to approximate what the atmosphere is likely to do before it actually does it.

Today’s technologies allow us to explore the atmosphere in extremely fine detail, but no matter how advanced these become, we should never forget to pair them with those that nature itself has provided—our senses.

Technology and the Atmosphere

Weather balloons—like those deployed by these cadets from the United States Merchant Marine Academy—collect data on weather conditions. An attached instrument, a radiosonde, measures temperature, pressure, and relative humidity.

Noun

layers of gases surrounding a planet or other celestial body.

Doppler effect
Noun

the increase or decrease in wave frequency, like light or sound, when the position of the wave source to the observer changes.

greenhouse gas
Noun

gas in the atmosphere, such as carbon dioxide, methane, water vapor, and ozone, that absorbs solar heat reflected by the surface of the Earth, warming the atmosphere.

in situ
Adjective

in something's original place or position.

ozone
Noun

form of oxygen that absorbs ultraviolet radiation.

radar
Noun

(RAdio Detection And Ranging) method of determining the presence and location of an object using radio waves.

radiosonde
Noun

instrument attached to a balloon that measures temperature, humidity, pressure, and other aspects of the atmosphere.

remote sensing
Noun

methods of information-gathering about the Earth's surface from a distance.

satellite
Noun

object that orbits around something else. Satellites can be natural, like moons, or artificial.

tornado
Noun

a violently rotating column of air that forms at the bottom of a cloud and touches the ground.

weather balloon
Noun

hydrogen-filled balloon equipped with tools to measure temperature, humidity, pressure, and other aspects of the atmosphere.