Nepedia
Back to Discover
Advanced Reader
🌍

Atmospheric physics

earth science Maturity 9-11 Next article →

Atmospheric physics is the application of physics to the study of the atmosphere. Scientists in this field work to model Earth's atmosphere and the atmospheres of other planets. They do this by using fluid flow equations to track how air moves. They also study the radiation budget and energy transfer processes. These processes often tie into boundary systems like the oceans. To model complex weather systems, they use highly mathematical tools. These include scattering theory, wave propagation models, and cloud physics. They also rely on statistical mechanics and spatial statistics to understand atmospheric behavior.

weather radar
weather radar

One essential method in this field is remote sensing. Remote sensing is the acquisition of information from an object without physical contact. Scientists use devices like aircraft, spacecraft, satellites, buoys, or ships to gather data. This "stand-off" collection allows for more information than single-site sensors can provide. There are two main types of remote sensing: passive and active. Passive sensors detect natural radiation that is emitted or reflected by an object. Reflected sunlight is the most common source for these sensors. Examples include film photography, infrared sensors, and radiometers.

Active collection works differently by emitting its own energy. An instrument scans an area by sending out energy and measuring what returns. This is known as backscattering. Techniques like radar, lidar, and SODAR are used in atmospheric physics. By measuring the time delay between emission and return, scientists determine an object's location, height, speed, and direction. Remote sensing is vital for studying dangerous or inaccessible areas. It helps monitor deforestation in the Amazon Basin and climate change in the Arctic and Antarctic. It also allows for the study of ocean depths without disturbing the environment.

seasons
seasons

Radiation is another central focus of atmospheric physics. Physicists divide radiation into solar radiation and terrestrial radiation. Solar radiation is emitted by the sun and contains many wavelengths. Visible light falls between 0.4 and 0.7 micrometers. Shorter wavelengths are called ultraviolet (UV), while longer ones are infrared. Ozone is very effective at absorbing UV radiation around 0.25 micrometers. This absorption increases the temperature of the stratosphere. Interestingly, different surfaces reflect UV rays differently. Snow reflects 88% of UV rays, while water reflects only 4%.

Terrestrial radiation is emitted by the Earth's surface and atmosphere. Because Earth is much colder than the sun, this radiation has much longer wavelengths. According to Planck's law, the wavelength of maximum energy for Earth is around 10 micrometers. Scientists also study cloud physics to understand how clouds form and grow. Clouds consist of microscopic water droplets, tiny ice crystals, or a mixed phase of both. Under certain conditions, these droplets combine to form precipitation. While the exact mechanics are not fully understood, researchers study the microphysics of individual droplets to build theories.

Lightning over Oradea Romania 3
Lightning over Oradea Romania 3

Atmospheric electricity involves the electrostatics and electrodynamics of the atmosphere. The Earth's surface, the atmosphere, and the ionosphere form the global atmospheric electrical circuit. Lightning is a major part of this system. A single lightning discharge can release 30,000 amperes and up to 100 million volts. It emits light, radio waves, X-rays, and even gamma rays. The plasma temperatures in lightning can approach 28,000 kelvins. Scientists also study atmospheric tides, which are regular fluctuations in wind, temperature, density, and pressure. Unlike ocean tides driven by the Moon, atmospheric tides are mostly generated by solar heating in the troposphere and stratosphere.

Upperatmoslight1
Upperatmoslight1

At the highest levels, the science of aeronomy begins. The term aeronomy was introduced by Sydney Chapman in 1960. It concerns the upper layers of the atmosphere where dissociation and ionization are important. Researchers use sounding rockets, balloons, and satellites to study these regions. They observe unique phenomena like red sprites, sprite halos, blue jets, and elves. Aeronomy also includes studying the atmospheres of other planets. This research is supported by many organizations, such as NOAA in the United States and the Met Office in the UK. By connecting these different layers and processes, atmospheric physics provides a complete picture of our planet's life-support system.

675 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (4)
File:weather radar.jpg
weather radar.jpg
File:seasons.svg
seasons.svg
File:Lightning over Oradea Romania 3.jpg
Lightning over Oradea Romania 3.jpg
File:Upperatmoslight1.jpg
Upperatmoslight1.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.