Today, how is information on stratospheric ozone levels tracked? Images and other data acquired by satellites flying far above Earth are used by scientists. Example of a response: More data is needed for scientists to determine how much of the depletion is attributable to human activities and how much is due to natural processes.
Why is it important for scientists to know how much ozone there is in the stratosphere? Ozone protects life on Earth by blocking out harmful ultraviolet radiation from the sun. However, humans are destroying the protective layer by emitting gases that destroy ozone molecules. The result is that more sunlight is able to reach the surface of the planet, which could lead to an increase in global warming.
Scientists use instruments aboard several different types of satellites to measure the amount of ozone in the stratosphere. These include NASA's Ozone Monitoring Instrument (OMI) and its predecessors the Solar Backscatter Ultraviolet Spectrometer (SBUV) and the Total Ozone Mapping Spectrometer (TOMS). OMI was designed and built by the British company Oxfam International in collaboration with students and researchers from dozens of countries. It measures the concentration of oxygen atoms in the atmosphere at different heights above the surface of the planet. These measurements are then compared to those taken over time to detect changes that may have occurred due to human activity or natural processes.
Increases in ozone near the Earth's surface are caused by man-made air pollution. The chemical and dynamical mechanisms that influence stratospheric ozone concentrations, as well as variations in stratospheric ozone abundance owing to historical and future anthropogenic impacts, will be examined.
Stratospheric ozone is a gas that shields earthlings from harmful ultraviolet (UV) radiation from the sun. It consists primarily of three molecules: O3, O4, and O2. Ozone levels are high in the atmosphere because they are constantly being created and destroyed through natural processes. Humans have altered the chemistry of the atmosphere by emitting gases that destroy ozone (such as CH4 and NOx), and by adding more ozone-destroying chemicals through the use of refrigerants, anesthetics, or pesticides that are released into the environment. As a result, ozone levels in the atmosphere are now at their highest level since measurements began in 1985.
Ozone protection efforts have been successful at reducing emissions of substances that destroy ozone (such as chlorofluorocarbons [CFCs] and methyl bromide). Since 1987, countries have agreed to protect ozone layers by limiting emissions of these substances. In addition, laws have been passed in many countries to phase out the use of CFCs in certain products like aerosol cans- this will help reduce emissions of CH4, which destroys ozone.
NASA's Ozone Watch meteorology program collects ozone concentrations via satellite equipment. We can observe that from 1979 to the early 1990s, stratospheric ozone concentrations in the Southern Hemisphere decreased to the worisome "ozone hole" threshold of 100 DU. Since 1994, however-thanks to international agreements-they have been recovering.
Ozone levels above 290 Dobson Units are considered unsafe for human activity. However, because of the variability in measurements made by different instruments, scientists prefer to use a statistical measure called the "8-hour average". This averages out the daily and seasonal variations in the atmosphere so that they do not influence the result. It also reduces the impact of clouds or rain that may cover the Earth for 8 hours each day.
The main method used by ozone watch is called "interferometry". Two satellites about the size of a small car are flown at slightly different angles so that their paths across the sky overlap in certain regions. When light from one satellite enters its telescope and is then reflected back into it from another satellite, some of this light will be scattered due to differences in air pressure between the two telescopes. The amount of scattering depends on the concentration of ozone near the spacecraft. By measuring the distance between the two telescopes when no scattering occurs (because both satellites are over land or ocean), scientists can calculate how much ozone there is between them.
Ground-based sensors have been used to monitor ozone since the 1920s. Scientists put devices across the world to measure the quantity of UV light that passes through the atmosphere at each location. They then use computers to analyze the data from these instruments.
Ozone is formed when ultraviolet radiation from the sun breaks down organic chemicals in clouds and aerosols. The oxygen atoms are then released into the atmosphere, where they combine with other molecules to form compounds such as NO2 and HO2. These substances are responsible for making Earth's atmosphere protective against harmful rays from space. However, too much of it is also dangerous because it can lead to increased exposure to sunlight, which can cause skin cancer and other health problems.
Ozone levels often remain relatively constant throughout most of the year, but they are particularly vulnerable to changes in weather patterns. A series of storms can blow away enough particles to lower local ozone levels, while periods of high sun exposure can break down more ozone molecules.
In recent years, scientists have also used satellites to measure atmospheric ozone. These instruments are able to continuously scan the planet's surface for UV light that has passed through the atmosphere. They can therefore provide information about global ozone levels not only at specific locations but also over time.
Following a more extensive investigation, scientists stated in 2016 that stratospheric ozone concentrations had been growing in the high stratosphere since 2000, while the extent of the Antarctic ozone hole had been reducing. These findings were based on measurements made by satellites and aircraft, as well as studies of historical data from ground-based observatories.
Scientists are concerned about the effects that increased ultraviolet radiation will have on the ozone layer because of continued use of chemicals known as chlorofluorocarbons (CFCs), which destroy ozone. CFCs were used in aerosol products such as spray cans before they were banned in 1994. They remain in the atmosphere even after they are emptied because they do not break down easily and instead decompose into molecules that contribute to global warming. Scientists also say that deforestation is another factor that can lead to reduced ozone levels because it allows more sunlight through to reach the earth's surface.
In conclusion, scientists state that there is some good news and some not so good news regarding the ozone layer. The good news is that it is recovering after decades of destruction caused by chemicals like CFCs. The not so good news is that it could still be destroyed entirely if current trends continue.