The ozone layer that is found in our upper atmosphere shields Earth from the damaging UV radiation’s harmful effects. Human-made substances in our environment for a long time reduced the ozone layer of Earth.
However, the decrease in the consumption of harmful ozone-depleting substances that are a result of the Montreal Protocol – an international treaty designed to safeguard the ozone layer enabled the ozone hole’s recovery to be slowly. This global agreement illustrates the power of international cooperation and urgent global action for protecting our surroundings.
ESA has been actively involved in the monitoring of ozone for more than two decades. Today is International Day for the Preservation of the Ozone Layer and we look closer look at the way satellite instruments observe the ozone layer that is over the South Pole.
Ozone’s atmospheric conditions vary naturally based on weather, temperature and latitude. But, these natural phenomena did not explain the degree of depletion that were observed at the end of the 1970s by scientists. They found that certain human-made chemical compounds, known as chlorofluorocarbons (CFCs) that are used in aerosol cans and refrigerators produced extremely low levels of ozone which occur across Antarctica between August and December every year.
Since the prohibition of CFCs The Ozone layer has begun to recover. Projections show that it will be been healed in the northern non-polar part of the hemisphere by 2030 as well as for the south by 2050s and in the Polar regions by 2060s.
The Ozone hole that will be over the South Pole in 2022
Size of the Ozone hole changes frequently. The ozone hole expands in its size from the month of August through October, and reaches its maximum in mid-September to mid-October.
As temperatures in the stratosphere begin increase within the Southern hemisphere the depletion of ozone slows down and the polar vortex becomes weaker and eventually breaks down and at mid-December,, ozone levels typically are back to normal levels.
In both 2021 and 2020 In both of these years, there were extremely large Ozone holes in the Antarctic and in the year 2019, there was a tiny Ozone hole due to extraordinary meteorological phenomena.
Diego Loyola, from the German Aerospace Center (DLR) stated: “Total ozone measurements from the Copernicus Sentinel-5P satellite created by DLR and DLR show that the ozone hole of this year began to open in mid-August and has an identical extension of around 23 million sq km by the middle of September, as in the years 2021 and 2020.”
Space-based observations of entire Ozone column – which is the entire thickness of the Ozone layer at the heart of the monitoring of the ozone layer, going from 1979 to provide daily data at a global scale.
However it is important to note that the complete ozone column doesn’t reveal the degree to which ozone is affected by the height. This is crucial as it reveals the way and at what elevation the depletion of ozone takes place and when the initial indicators of recovery likely. Additionally, how climate impacts stratospheric Ozone, is dependent on the altitude.
There are many ways to study how ozone levels change as altitude increases. Downward-facing satellites and their instruments, particularly ones that measure reflections of visible and ultraviolet solar radiation like SCIAMACHY, OMI, GOME-2 and Copernicus Sentinel-5P’s Tropomi are also capable of finding an estimate of the distribution vertically of ozone to allow for daily surveillance of the Antarctic Ozone hole.
New images released by the Royal Netherlands Meteorological Institute (KNMI) illustrate how vertically distributed the ozone layer in an area that is a cross-section of the circumpolar vortex (wind fields) which creates an organic border between regions with high levels of ozone as well as the ozone hole that is located over the South Pole.
The first time Tropomi Ozone profile measurements are utilized to track the ozone hole that is over the South Pole.
Pepijn Veefkind senior scientist at KNMI and KNMI, stated, “In the short ultraviolet wavelengths, light that is reflected by the upper layers of the atmosphere scatter back to Tropomi is measured. As wavelengths increase increasing, more that measured light gets scattered back by upper layers in the atmospheric. It allows us to calculate the ozone profile at the vertical resolution of 6-10 kilometers.”
The satellite-based observations will likely be in use throughout into the 20th century. It is believed that the European Copernicus satellite programme and in particular, the Sentinel-4 satellite mission are already scheduled to continue for the future beyond 2040 as well as to monitor the atmospheric conditions.
Satellites also have the ability to look at the atmosphere from the sides, which is also known as ‘limb’ observation. The advantage of these images is their ability to layer vertically specific. But the drawback is that they don’t give a complete global view. In addition, many of these satellites for limbs are old or decrepit and a lot of them will never be replaced.
Claus Zehner, Sentinel-5P, Altius and Flex Missions Manager, commented, “The upcoming Atmospheric Limb Tracker for Investigation of the Upcoming Stratosphere also known as Altius mission, will fill in a crucial gap in the development of “limb” measurements for atmospheric science. It will provide higher vertically-resolved ozone profiles spatial resolution as well as better understanding of the monitoring of trends in ozone.”
The mission is equipped with an imager with high resolution and will produce profiles of ozone as well as other trace gases found in the upper atmosphere in order to facilitate services like forecasting weather, and also to observe long-term trends in ozone at various altitudes.
Altius is set to launch in 2025 aboard the Vega-C rocket coming from the European Spaceport situated in Kourou, French Guiana.
Find out more information details about this mission on Altius.
Copernicus Service on ozone monitoring
The Copernicus Atmosphere Monitoring Service ( CAMS) is operated through the European Centre for Medium-Range Weather Forecasts ( ECMWF) It provides a range of information to track the ozone hole, and to predict how it will alter in the near future.
CAMS integrates measurements from satellite instruments, such as Sentinel-5P and in-situ sensors along with its numerical models to offer high-quality information on the condition of the layer that is known as the Ozone and forecasts of the condition of the Ozone hole.
The current status of the in progress ozone hole can be seen below in 3D animated animation.