Ozonedepleting substances are present throughout the stratospheric ozone layer because they are transported great distances by atmospheric air motions. The ozone hole is formed each year in the southern hemisphere spring septembernovember when there is a sharp decline currently up to 60% in the total ozone over most of antarctica. Observing the latest sevenday total ozone images, answer the following questions. Ozone hole three times the size of greenland opens over. The ozone hole area is determined from total ozone satellite measurements. By summertime, stratospheric air from lower latitudes is able to penetrate the polar latitudes, and thereby replenish the ozone layer above antarctica.
In the early 1980s, scientists began to realize that cfcs were creating a thin spota holein the ozone layer over antarctica every spring. Scientists have detected what may be the largest hole in the ozone layer ever recorded over the north pole. The ozone depletion process the discovery of the antarctic ozone hole the first decreases in antarctic total ozone were observed in the early 1980s over research stations located on the ant arctic continent. What is the ozone hole, and why has it formed over antarctica. The antarctic ozone hole from discovery to the present day. Also again in 2011 an ozone hole appeared over mountainous regions of tibet, xinjiang, qinghai and the hindu kush, along with an unprecedented hole over the arctic, though the tibet one is far less intense than the ones over the arctic or antarctic.
The ozone hole we observe over the arctic this year has a maximum extension of less than 1 million sq km. Pdf reduced perchlorate in west antarctica snow during. Each winter a polar vortex forms in the stratosphere over the antarctic. Pdf absorption of solar radiation by stratospheric ozone affects atmospheric dynamics and chemistry, and sustains life on earth by preventing harmful.
The ozone hole covers an area roughly three times the size of. Mini ozone hole opens over arctic and, yes, thats kinda. Analyzing the antarctic ozone hole is geared toward students in grades 710 and is designed to be completed in two hours or less. An ozone hole has developed over the arctic, a rare occurrence that. Manney said, the amount of ozone that was destroyed was comparable to what we saw a couple of decades ago in the southern hemisphere, when we first started studying the antarctic ozone hole.
The ozone layer in antarctica oceanwide expeditions. Satellite spots new ozone layer hole opening up over the. Ozone in the stratosphere is being depleted by a variety of humanmade gases with a hole forming over antarctica. Apr 14, 2017 for more information about how uv affects humans, you can download the practical guide to the global uv index 429 kb pdf. Jonathan shanklin at the british antarctic survey discovers the ozone hole over the antarctic. Reduced perchlorate in west antarctica snow during stratospheric ozone hole article pdf available in antarctic science 293. Ozone amounts are broadly uniform across the continent. This series of satellite images shows the ozone hole on the day of its maximum depth each year from 1979 through 2019. Ozone layer and the formation of the ozone hole aa. Scientists have calculated that if the ozone layer was brought down to sea level it would be 3 mm thick, while in the antarctic the ozone can be as low as 1 mm thick. The ozone hole over antarctica is worrisome, but on that frozen continent there are few animals and fewer people for harmful uv rays to damage. Normal ozone ozone layer depletion and its effects.
Unlike the hole that developed over the arctic, the antarctic ozone hole in the southern hemisphere is typically caused by chemicals such. Apr 26, 2020 view the latest status of the ozone layer over the arctic. Ozone hole over antarctica shrinks to recordsmall size. In the antarctic, winter temperatures in the stratosphere are persistently cold enough to create polar stratospheric cloudsand a large, severe ozone hole. In winter in the polar stratosphere of the southern hemisphere a. The thinning of the ozone layer is caused by a chemical reaction where man. They discovered a general thinning over the whole globe a 3% decrease since 1969, but with greater depletions in middle and higher northern latitudes. Mini ozone hole opens over arctic and, yes, thats kinda weird. Why has an ozone hole appeared over antarctica when ozone depleting. The stratospheric response to antarctic sea ice loss is relatively. In the early 1980s, scientists began to realize that cfcs were creating a thin spota hole in the ozone layer over antarctica every spring. The antarctic ozone hole in the southern hemisphere is known for its yearly variations. Antarctica is home to our usual hole in the ozone layer.
But instead, we are observing an annual ozone hole in one of the most pristine places left on the planet, located in the southern hemisphere, in a place called antarctica. Most eyes are fixed on the skies over antarctica, but now scientists have. Apr 14, 2020 the lesserdamaged ozone over the north pole is expected to heal by about 2040. Pdf on oct 1, 2016, tanmoy mukherjee and others published splitting of ozone hole over antarctica its effect on total column ozone and its.
In the past weeks, scientists from the german aerospace center dlr have noticed the unusually strong depletion of ozone over the northern polar regions. The largest arctic ozone hole ever recorded is now closed. The unexpected discovery of a hole in the atmospheric ozone layer over the antarctic revolutionized science and helped to establish one of the most successful global environmental policies of. Emergence of healing in the antarctic ozone layer oceans at mit.
Unusual winds drive a small 2019 ozone hole youtube. Click any map image to bring up a new page with a highresolution image. Second ozone hole of record breaking size reported over. Ozone hole over the arctic by european space agency. However, when ozone depleted air moves from antarctica northwards to more populated regions like australia and new zealand, it can become a serious health concern. Although a hole in the ozone layer might sound like a decidedly retro environmental issue, its still a problem today.
We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over antarctica. These wavelengths cause skin cancer, sunburn and cataracts, which were projected to increase. But in some positive news since the incident, scientists who have been observing the ozone hole at copernicus atmospheric monitoring service cams has announced that the hole is now closed. Jonathan shanklin discovers the ozone hole over the antarctic. National aeronautics and the ozone hole space administratio n. At a glance it could be fully repaired by the middle or end of this century, a new study says. Ozone in the stratospherea layer of the atmosphere between 15 and 50. The antarctic ozone hole opens up in austral spring of each year, and is measured both by its depth typically a loss of about half of the total. In the 1980s, the discovery of a gaping hole in the ozone layer over antarctica drew international dismay and, in 1987, culminated in the montreal protocol, an. View the latest status of the ozone layer over the antarctic, with a focus on the ozone hole.
The ozone depletion processs 33 why has an ozone hole appeared over antarctica when ozone depleting substances are present throughout the stratosphere. Largest ozone hole ever seen over arctic has healed. What is an ozone hole and causes and effects of ozone. It can be assigned directly to students, or used as a professional development activity to familiarize teachers with accessing and analyzing satellite data. In the measurements made in recent times significant reductions in ozone concentrations in the layer, with special. Technically, the term ozone hole should be applied to regions where stratospheric ozone depletion is so severe that levels fall below 200 dobson units d. The ozone loss bottoms out for the season, and the ozone layer gradually regenerates over the summer. When it comes to the ozone hole, chlorine is the enemy. The secular trend of the antarctic ozone hole has been studied with a twodimensional model which can simulate formation of polar stratospheric clouds and includes heterogeneous chemical reactions.
Jan 06, 2020 however, the ozone loss was not as severe as that in the annual antarctic ozone hole, which has grown in size and intensity over the last twenty years. There, without sunlight, temperatures drop to as low as. The ozone hole above antarctica, where the suns harmful ultraviolet uv rays bust through an otherwise sunscreened stratosphere, has shrunk. In this study we consider the impact of stratospheric ozone depletion on antarctic sea ice extent using a climate model forced with observed stratospheric ozone depletion from 1979 to 2005. During what months do the lowest values of ozone occur over the antarctic. Decribe briefly a popular hypothesis to form the ozone holes above the south pole in spring.
The ozone hole over antarctica is healing according to a study published in the journal science. Ozone naturally forms when oxygen is exposed to ultraviolet radiation from the sun. Firstly, strong circular winds form that blow around the whole continent, this is known as the polar vortex this isolates the air over antarctica from the rest. The ozone hole over antarctica nears its record youtube. Ozone hole shrinks to smallest size on record, and its not related to global warming a polar vortex is a large area of cold air high in the atmosphere that normally spins over the. Ozone layer the antartic ozone hole young peoples trust. Just as suddenly as it first formed, a recordbreaking ozone hole has healed. Estimate the range of dobson units over the antarctic pole. Publication date 1011998 topics planetearth, earth science, what sun, where goddard space flight center gsfc in 1985, a british scientist working in antarctica discovered a 40 percent loss in the ozone layer over the continent. The ozone hole in antarctica cool antarctica, pictures. Ozone hole over antarctica shrinks to smallest peak since. This animation shows the daily ozone levels over the arctic from march 9, 2020, until april 1, 2020.
Ozone hole over antarctica is healing, scientists say the. The largest ozone hole to ever open up over the arctic is now closed, after first opening up earlier this spring. In this chapter you will download images showing the concentration of ozone over the southern hemisphere, and learn to identify the antarctic ozone hole in them. The ozone layer prevents most harmful uv wavelengths of ultraviolet light uv light from passing through the earths atmosphere. Largest ozone hole ever recorded over north pole has now. The lowest ozone values, around 270 du, are over coastal west antarctica. Well, first of all, let me tell you that the ozone hole is not really a hole. The chlorine comes from chlorofluorocarbons cfcs, for short, which were widely used in early refrigeration and cooling systems.
Csiro advises that the information contained in this publication comprises general statements based on scientific research. The 2017 antarctic ozone hole summary department of the. Nov 03, 2017 ozone hole over antarctica shrinks to smallest peak since 1988. Why has an ozone hole appeared over antarctica when. Abnormal weather patterns in the upper atmosphere over antarctica dramatically limited ozone depletion in september and october, resulting in the smallest ozone hole observed since 1982, nasa and noaa scientists reported today. National institute of water and atmospheric research niwa, lauder, central otago, new zealand abstract. Contrasting the antarctic and arctic atmospheric responses. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are.
The ozone hole most commonly referenced is the hole over antarctica, forming each year during autumn. During the cold dark antarctic winter, stratospheric ice clouds pscs, polar stratospheric clouds form when temperatures drop below 78c. It is found that the antarctic ozone hole juneseptember is controlled by the halogen cycles at about 9095% cloclo, broclo, and cloo and the loss above 700 k is dominated by the. During the antarctic winter something special happens to the antarctic weather. Record ozone hole disappears over the arctic just weeks after being discovered holes in the ozone layer typically develop over antarctica, so the new hole over the north pole was quite concerning. Also, the tropospheric response to antarctic sea ice loss is found to be somewhat weaker, more vertically con. In a recent study the ozone hole found over your head during an antarctica expedition was found to be showing evidence of a decrease in size based on 15 years of ground and satellite observations with the size of the ozone hole in 2014 less severe compared to the 19952005 average. Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. Ozone depletion is taking place at a rate of a few percent per year, most noticeably at the midlatitudes of the planet. Oct 23, 2019 the unexpected discovery of a hole in the atmospheric ozone layer over the antarctic revolutionized science and helped to establish one of the most successful global environmental policies of. Contrary to expectations, our model simulates a year.
The stability of the stratospheric ozone layer has attracted the interest of scientists, the pub lic and policymakers for more than 50 years because this layer protects life on earths surface from biologically damaging ultraviolet figure 1 ozone over antarctica. Watch a movie of the daily progression through a season or the annual progression of the. How the ozone hole forms the ozone hole is not really a hole but a thinning of the ozone layer over the south polar region. A rare ozone hole is open over the arctic earth earthsky. The ozone hole occurs during the antarctic spring, from september to early december, as strong westerly wind start to circulate around the continent and create an atmospheric container. The antartic ozone hole a hole in the ozone layer, covering an area larger than the antarctic continent, was discovered in 1985 by joe farman and his colleagues on the british antarctic survey. Ozone hole is the area of the earths atmosphere where abnormal reductions of ozone occur, it is an annual phenomenon observed during the spring in the polar regions and is usually followed by a recovery during the summer. The antarctic ozone hole, a rapid depletion of ozone that occurs each spring over antarctica, first formed more than 30 years ago. Considering the fact that this second hole is the largest so far over the earths northernmost regions, we might be in serious trouble if we dont act quick before it grows bigger or more holes appear. A hole in the ozone opens up every year above antarctica but scientists were surprised to find one on the other side of the planet. The measurements were made with groundbased dobson spectrophotometers see box in q5. The ozone depletion process the discovery of the antarctic ozone hole the first decreases in antarctic total ozone were observed in the early 1980s over research stations located on the antarctic continent.
With the 1985 discovery of an ozone hole over antarctica, an. Eric ej802492 the antarctic ozone hole, physics education. In this container over 50% of the lower stratospheric ozone is destroyed. The ozone hole is an annual thin spot that forms in the stratospheric ozone layer over antarctica in midseptember and october.
Largestever arctic ozone hole closes the independent. The ozone hole forms each year when there is a sharp decline currently up to 60% in the total ozone over most of antarctica for a period of about two months during september and october. A vast ozone hole probably the biggest on record in the north has opened in the skies above the arctic. The term ozone hole refers to a phenomenon observed yearly over the south. This is small compared to the antarctic hole, which can reach a size of around 20 to 25 million sq km with a normal duration of around 3 to 4 months, diego loyola from the german aerospace center told esa. Since the mid 1970s, the ozone layer over antarctica has experienced massive destruction during every spring. The 2018 ozone hole is over and the southern polar vortex has dissipated. Oct 23, 2015 the ozone hole over antarctica currently extends over 26 million square kilometres an area larger than the north american continent. Why this rare, huge ozone hole over the arctic is puzzling. Though in 2019, the ozone hole over antarctica was reported to be at its smallest ever, as its size fluctuates every year. Largest arctic ozone hole ever recorded opens up over the. Scientists who were tracking the hole at the copernicus atmospheric monitoring service cams said it reached its maximum size in march at about 11 miles above the surface of the earth. Pdf the signs of antarctic ozone hole recovery researchgate.
The ozone hole is an area where the amount of ozone in the upper atmosphere is much lower than normal. Every year, since at least 1978, there is a sudden, rapid decrease in the stratospheric ozone levels at the end of the antarctic winter. Pdf splitting of ozone hole over antarctica its effect on total. Antarctic situation at 2019 january 28 british antarctic survey ozone bulletin. Record ozone hole disappears over the arctic just weeks. It rivals the betterknown antarctic ozone hole that forms in the. The antarctic ozone hole cool antarctica, pictures of. While it may be encouraging that we have a predictive scale for recovery of the hole in the ozone, there is another concern. Pdf global ozone depletion and the antarctic ozone hole. The ozone hole is caused by the effect of pollutants in the atmosphere destroying stratospheric ozone. Ozone depleting substances are present throughout the stratospheric ozone layer because they are transported great distances by atmospheric air motions. Apr 26, 2020 view the latest status of the ozone layer over the antarctic, with a focus on the ozone hole. Values below 220 du represent anthropogenic ozone losses over antarctica. When you hear about an ozone hole, its typically the one that forms over antarctica each.
Recordbreaking arctic ozone hole closes, but not due to. Measurements from satellitebased instruments show that this area of very low ozone concentration has developed over antarctica every year since about 1975. The severe depletion of stratospheric ozone in late winter and early spring in the antarctic is known as the ozone hole see q11. Why has an ozone hole appeared over antarctica when ozone.
1311 93 688 798 1196 69 1404 185 1062 710 1269 596 54 164 867 285 299 689 181 1514 1160 653 898 684 947 550 670 365 1078 921 183 162 569 320 1223 1223 1388