Situation at 2011 December 26British
Antarctic Survey Ozone Bulletin
The 2011 Antarctic ozone hole is
over, with the weak summer circulation now established. The hole began to form
in mid August, and by mid September had reached an area of around 25 million
square kilometres, larger than the average for the last decade and remained near
this size into early October. It had shrunk to around 20 million square
kilometres by mid October and remained a similar size till mid November, when
its size dropped rapidly but remained at a few million square kilometres until
mid December. It filled by the summer solstice. Its size from October to mid
November was near to or above the record area for the time of year. The hole
became more elliptical in mid October and the edge of the ozone hole passed over
the tip of South America and the Falkland Islands, but then returned to a more
circular form. Minimum ozone values are currently around 250 DU. Maximum values
are near 340 DU, but they are subsiding from peaks above 400 DU. The lower
stratospheric temperature is near its summer peak, though temperatures remain
below the normal for this time of year. The edge of the ozone hole passed over
the tip of South America around September 26 to 28, October 9, 16 to 19. The
edge again passed over this area from November 7 to 8. Significant differences
between the various satellite analyses of ozone distribution remain.
Although the amount of ozone
destroying substances in the atmosphere is going down, the inter-annual
variation in the size and depth of the ozone hole is largely controlled by the
meteorological conditions in the stratosphere. This year the polar vortex was
cold and stable, allowing substantial ozone depletion. It is still too soon to
say that we have had the worst ever ozone hole.
There was substantial Arctic ozone
depletion over the northern winter in 2011. As 2012 approaches, the northern
circulation pattern is returning to the winter mode, with some parts of the
lower stratosphere already below the PSC formation temperature. The minimum
temperatures are close to the seasonal extreme. Arctic ozone levels are within
30% of normal, with areas that are higher and lower than the mean.
The ozone hole area is determined from total ozone satellite
measurements. It is defined to be that region of ozone values below 220 Dobson
Units (DU) located south of 40°S. Values below 220 DU represent anthropogenic
ozone losses over Antarctica.
The minimum ozone is found from total ozone satellite
measurements south of 40°S. No interpolation of missing values is performed.
This means that the actual minimum value on a day may be estimated too high,
especially in the polar night region.
The ozone mass deficit is determined from total ozone satellite
measurements. It combines the effects of changes in area and depth. It is the
total amount of mass that is deficit relative to the amount of mass present for
a value of 220 Dobson Units (DU).
Time series of the volume of the region where temperatures are low enough for
the formation of nitric acid trihydrate (NAT or PSCs of type I). The red curve
shows 2011 (until 2 December). The blue and green curves represent 2010 and
2009, respectively. The average of the 1979-2010 period is shown for comparison
in black. The two thin black lines show the maximum and minimum PSC area during
the 1979-2010 time period for each date. The light blue-green shaded area
represents the 10th and 90th percentile values and the dark blue-green shaded
area the 30th and 70th percentiles. The plot is made at WMO based on data
downloaded from the Ozonewatch web site at NASA, which are based on data from
NOAA/NCEP.
The 2011 Ozone Hole reached it’s largest size of 26 million square kilometers on
September 12,2011
The lowest concentration of ozone in the southern stratosphere—that is, the
deepest “hole”—occurred on October 8, 2011 when levels descended to 95 Dobson
units
Situation at 2011 December 13British
Antarctic Survey Ozone Bulletin
The 2011 Antarctic ozone hole is
nearly over, with the remnant area of low ozone centred over Princess Elizabeth
Land. Minimum values within the polar vortex are around 210 DU. The hole began
to form in mid August, and by mid September had reached an area of around 25
million square kilometres, larger than the average for the last decade and
remained near this size into early October. It had shrunk to around 20 million
square kilometres by mid October and remained a similar size till mid November,
when it s size dropped rapidly and now covers a few million square kilometres.
It will have filled by the summer solstice. Its size from October to mid
November was near to or above the record area for the time of year. The hole
became more elliptical in mid October and the edge of the ozone hole passed over
the tip of South America and the Falkland Islands, but then returned to a more
circular form. The circum-polar ozone belt outside the vortex has some areas
near 350 DU, but maximum levels are subsiding from peaks above 400 DU. The lower
stratospheric temperature is well past its winter minimum, and warming is well
under way, though temperatures remain substantially below the normal for this
time of year. All of the Antarctic ozone layer is now above the polar
stratospheric cloud formation temperature. The edge of the ozone hole passed
over the tip of South America around September 26 to 28, October 9, 16 to 19.
The edge again passed over this area from November 7 to 8. Significant
differences between the various satellite analyses of ozone distribution remain.
Situation at 2011 December 5British
Antarctic Survey Ozone Bulletin
The Antarctic ozone hole is centred
over the eastern Weddell Sea and is slowly filling. Minimum values within the
polar vortex are around 200 DU. The 2011 hole is predicted to be over by mid
December. The hole began to form in mid August, and by mid September had reached
an area of around 25 million square kilometres, larger than the average for the
last decade and remained near this size into early October. It had shrunk to
around 20 million square kilometres by mid October and remained a similar size
till mid November, when it dropped rapidly and is now around 5 million square
kilometres. Its size from October to mid November was near to or above the
record area for the time of year. The hole became more elliptical in mid October
and the edge of the ozone hole passed over the tip of South America and the
Falkland Islands, but then returned to a more circular form. The circum-polar
ozone belt outside the vortex has some areas near 350 DU, particularly between
the continent and Australia, but maximum levels are subsiding from peaks above
400 DU. The lower stratospheric temperature is well past its winter minimum, and
warming is under way, though temperatures remain substantially below the normal
for this time of year. All of the Antarctic ozone layer is now above the polar
stratospheric cloud formation temperature. The edge of the ozone hole passed
over the tip of South America around September 26 to 28, October 9, 16 to 19.
The edge again passed over this area from November 7 to 8. Significant
differences between the various satellite analyses of ozone distribution remain.
Situation at 2011 November 28British
Antarctic Survey Ozone Bulletin
The Antarctic ozone hole is now
centred over the eastern Weddell Sea and is slowly filling. The hole began to
form in mid August, and by mid September had reached an area of around 25
million square kilometres, larger than the average for the last decade and
remained near this size into early October. It had shrunk to around 20 million
square kilometres by mid October and remained a similar size till mid November,
when it dropped to around 14 million square kilometres. Its size during October
and November has been near to or above the record area for the time of year.
Ozone depleted air remains over Antarctica and the Weddell Sea, but the ozone
hole is now filling. Minimum values within the polar vortex are around 200 DU.
The hole became more elliptical in mid October and the edge of the ozone hole
passed over the tip of South America and the Falkland Islands, but then returned
to a more circular form. The circum-polar ozone belt outside the vortex has some
areas near 370 DU, particularly between the continent and Australia, but maximum
levels are subsiding from peaks above 400 DU. The lower stratospheric
temperature is well past its winter minimum, and warming is under way, though
temperatures remain substantially below the normal for this time of year. All of
the Antarctic ozone layer is now above the polar stratospheric cloud formation
temperature, though clouds can still exist. The edge of the ozone hole passed
over the tip of South America around September 26 to 28, October 9, 16 to 19.
Significant differences between the various satellite analyses of ozone
distribution remain.
Situation at 2011 November 24British
Antarctic Survey Ozone Bulletin
The Antarctic ozone hole is now
centered off the coast of the Antarctic Peninsula and is slowly filling. The
hole began to form in mid August, and by mid September had reached an area of
around 25 million square kilometres, larger than the average for the last decade
and remained near this size into early October. It had shrunk to around 20
million square kilometres by mid October and remained a similar size till mid
November, when it dropped to around 14 million square kilometres. Its size
during October and November has been near to or above the record area for the
time of year. Ozone depleted air remains over Antarctica and the Weddell Sea,
but the ozone hole is now filling. Minimum values within the polar vortex are
around 180 DU. The hole became more elliptical in mid October and the edge of
the ozone hole passed over the tip of South America and the Falkland Islands,
but then returned to a more circular form. The circum-polar ozone belt outside
the vortex has some areas near 370 DU, particularly between the continent and
Australia, but maximum levels are subsiding from peaks above 400 DU. The lower
stratospheric temperature is well past its winter minimum, and warming is under
way, though temperatures remain substantially below the normal for this time of
year. All of the Antarctic ozone layer is now above the polar stratospheric
cloud formation temperature, though clouds can still exist. The edge of the
ozone hole passed over the tip of South America around September 26 to 28,
October 9, 16 to 19. The edge is again expected to pass over this area from
November 7 to 8. Significant differences between the various satellite analyses
of ozone distribution remain.
Situation at 2011 November 14British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of around 25 million square
kilometres, larger than the average for the last decade. It remained near this
size into early October, but had shrunk to around 20 million square kilometres
by mid October. Its size during October has been near to the record area for
this time of year and by the end of the month it was a record size for the time
of year. It remained at around 19 million square kilometres in mid November.
Ozone depletion remains widespread over Antarctica with much of the continent
under the ozone hole, which is now filling. Minimum values within the polar
vortex are around 150 DU. The hole became more elliptical in mid October and the
edge of the ozone hole passed over the tip of South America and the Falkland
Islands, but then returned to a more circular form. The circum-polar ozone belt
outside the vortex has some areas near 400 DU, particularly between the
continent and Australia, but maximum levels are subsiding. The lower
stratospheric temperature is past its winter minimum, and warming is generally
under way, but it is significantly below the normal for this time of year. All
of the Antarctic ozone layer is now above the polar stratospheric cloud
formation temperature, though clouds can still exist. The edge of the ozone hole
passed over the tip of South America around September 26 to 28, October 9, 16 to
19. The edge is again expected to pass over this area from November 7 to 8.
Significant differences between the various satellite analyses of ozone
distribution remain.
Situation at 2011 November 7British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of around 25 million square
kilometres, larger than the average for the last decade. It remained near this
size into early October, but had shrunk to around 20 million square kilometres
by mid October. Its size during October has been near to the record area for
this time of year and by the end of the month it was a record size for the time
of year. It remained at around 20 million square kilometres in early November.
Ozone depletion remains widespread over Antarctica with much of the continent
under the ozone hole. Minimum values within the polar vortex are below 150 DU.
The hole became more elliptical in mid October and the edge of the ozone hole
passed over the tip of South America and the Falkland Islands, but then returned
to a more circular form. The circum-polar ozone belt outside the vortex has some
areas near 400 DU, particularly between the continent and Australia, but maximum
levels are subsiding. The lower stratospheric temperature is past its winter
minimum, and warming is generally under way, but some of the Antarctic ozone
layer remains below the polar stratospheric cloud formation temperature, and
significantly below the normal for this time of year. The temperature at 30 hPa
and higher is now above the PSC formation temperature. The edge of the ozone
hole passed over the tip of South America around September 26 to 28, October 9,
16 to 19. The edge is again expected to pass over this area from November 7 to
8. Significant differences between the various satellite analyses of ozone
distribution remain.
Situation at 2011 October 31British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of around 25 million square
kilometres, larger than the average for the last decade. It remained near this
size into early October, but had shrunk to around 20 million square kilometres
by mid October. Its size during October has been near to the record area for
this time of year and by the end of the month it was a record size for the time
of year. Ozone depletion remains widespread over Antarctica with much of the
continent under the ozone hole. Minimum values within the polar vortex are below
150 DU. The hole became more elliptical in mid October and the edge of the ozone
hole passed over the tip of South America and the Falkland Islands, but is now
returning to a more circular form. The circum-polar ozone belt outside the
vortex has some areas near 400 DU, particularly between the continent and
Australia, but maximum levels are subsiding. The lower stratospheric temperature
is past its winter minimum, but much of the Antarctic ozone layer remains well
below the polar stratospheric cloud formation temperature, and below the normal
for this time of year. The temperature at 10 hPa and higher is now above the PSC
formation temperature. The edge of the ozone hole passed over the tip of South
America around September 26 to 28, October 9, 16 to 19.
Situation at 2011 October 24British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of around 25 million square
kilometres, larger than the average for the last decade. It remained near this
size into early October, but has now shrunk to around 20 million square
kilometres. Its size during October has been near to the record area for this
time of year. Ozone depletion remains widespread over Antarctica with much of
the continent under the ozone hole. Minimum values within the polar vortex are
below 140 DU. The hole became more elliptical in mid October and the edge of the
ozone hole passed over the tip of South America and the Falkland Islands, but is
now returning to a more circular form. The circum-polar ozone belt outside the
vortex has some areas above 400 DU, particularly between the continent and
Australia and south of Kerguelen. The lower stratospheric temperature is past
its winter minimum, but much of the Antarctic ozone layer remains below the
polar stratospheric cloud formation temperature, and below the normal for this
time of year. The temperature at 10 hPa and higher is now above the PSC
formation temperature. The edge of the ozone hole passed over the tip of South
America around September 26 to 28, October 9, 16 to 19.
October 18, 2011-The
Ozone Hole Reaches South America
Situation at 2011 October 17British
Antarctic Survey Ozone Bulletin
The ozone hole
began to form in mid August, and by mid September had reached an area of around
25 million square kilometres, larger than the average for the last decade. It
remained near this size into mid October, with a near record area for this time
of year, but is now shrinking and covers 21 million square kilometres. Ozone
depletion remains widespread over Antarctica with much of the continent under
the ozone hole. Minimum values within the polar vortex are below 140 DU. The
hole has become more elliptical and the edge of the ozone hole is predicted to
pass over the tip of South America and the Falkland Islands over the next few
days. The circum-polar ozone belt outside the vortex has some areas above 400
DU, particularly between the continent and Australia. The lower stratospheric
temperature is past its winter minimum, though some of the Antarctic ozone layer
remains below the polar stratospheric cloud formation temperature. The lower
stratospheric temperature is below the normal for this time of year. The edge of
the ozone hole passed over the tip of South America around September 26 to 28.
October 15,2011
NOAA Antarctic Ozone Hole Reaches Annual Maximum
At 25 million square kilometers (about 9.7 million square miles), the ozone hole
over the South Pole reached its maximum annual size on September 14, 2011. This
year’s hole was the 5th largest on record, as documented by the SBUV/2 sensor on
board the NOAA POES spacecrafts. Since its discovery in the late 1970’s with the
first satellite mission that could measure ozone, the hole continued to grow in
its annual maximum area steadily throughout the 1980’s and 90’s. Since the early
2000’s, the growth has leveled off, but there is still large variability from
year to year. The international banning of ozone-destroying oxidizing chemicals
like CFC’s (chlorofluorocarbons) has helped reduce the loss of ozone, which
protects Earth from harmful ultraviolet energy from the sun. As these
ozone-destroying compounds slowly break down in the stratosphere, years with
large ozone holes are now more associated with very cold winters over Antarctica
and high polar winds that prevent the mixing of ozone rich air outside of the
polar circulation with the ozone depleted air inside.
Shown here is the total ozone concentration over the South Pole on September 14,
2011. The “hole” is designated as the area where the total ozone concentration
is below 220 Dobson units (a measure of thickness). In this image, those values
are colored red. To put the 2011 maximum ozone hole size in context with that of
past decades, the approximate size of 1981 and 1991 maximum hole areas are also
shown. The ozone “hole” is not a complete depletion of ozone throughout the
entire atmosphere, but rather the partial or complete depletion of ozone between
14-22 km above the surface.
On October 27, 2011, the NASA NPP
satellite will launch, bringing with it continued observations of the ozone
layer with the Ozone Mapper Profiler Suite. The advanced sensors on OMPS will be
used by NOAA to provide more accurate measurements of the total area of the
ozone hole while also measuring how the concentration of ozone changes
vertically throughout the atmosphere.
Antarctic Ozone Bulletin No 4 / 2011 30 September 2011
WMO Antarctic Ozone Bulletin
Satellite
observations show that the area where total ozone is less than 220 DU (“ozone
hole area”) is average compared to recent years. In late September, the ozone
hole area is smaller than the ozone hole of 2008 but larger than in 2009 and
2010.
The sun has now returned to all of Antarctica after the polar night, and ozone
destruction is now slowing down compared to two weeks ago. The area of the ozone
hole is now near or at its maximum for the season, whereas the ozone mass
deficit might continue to increase for another week or so. The development of
ozone depletion so far in combination with the temperature conditions and the
extent of polar stratospheric clouds indicate that the degree of ozone loss will
be about average in comparison to the ozone holes of the last decade. However,
the relatively large amounts of active chlorine could lead to a somewhat
prolonged period of ozone loss compared recent years.
The ozone hole area for the years from 2004 to 2011. 2011 is shown with black
dots. The ozone hole area is the area of the region where total ozone is below
220 DU. The open circles represent a forecast for the five next days. During the
two weeks since the last Bulletin, which showed data as of 1 September, the area
of the ozone hole has increased from 10 to 24 million km2. This plot is produced
by KNMI and is based on data from the GOME and SCIAMACHY satellite instruments.
Situation at 2011 September 30British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of around 24 million square
kilometres, larger than the average for the last decade. It remains near this
size. Ozone depletion is now widespread over Antarctica with much of the
continent under the ozone hole. Minimum values within the polar vortex are below
120 DU. The circum-polar ozone belt outside the vortex has some areas above 400
DU. The lower stratospheric temperature is near its winter minimum, with much of
the Antarctic ozone layer below the polar stratospheric cloud formation
temperature. The lower stratospheric temperature is below the normal for this
time of year.
September 27, 2011-The
Ozone Hole Reaches South America
Situation at 2011 September 23British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of 25 million square
kilometres, larger than the average for the last decade. Ozone depletion is now
widespread over Antarctica with much of the continent under the ozone hole.
Minimum values within the polar vortex are below 130 DU. The circum-polar ozone
belt outside the vortex has some areas above 400 DU. The lower stratospheric
temperature is near its winter minimum, with much of the Antarctic ozone layer
below the polar stratospheric cloud formation temperature. The lower
stratospheric temperature is below the normal for this time of year. The edge of
the ozone hole is expected to pass over the tip of South America around
September 26 to 28.
International Day for the Preservation of the Ozone Layer
Situation at 2011 September 16
(World Ozone Day)British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by mid September had reached an area of 25 million square
kilometres, larger than the average for the last decade. Ozone depletion is now
widespread over Antarctica with much of the continent under the ozone hole.
Minimum values within the polar vortex are below 160 DU. The circum-polar ozone
belt outside the vortex has some areas above 400 DU. The lower stratospheric
temperature is near its winter minimum, with much of the Antarctic ozone layer
below the polar stratospheric cloud formation temperature. The lower
stratospheric temperature is below the normal for this time of year.
Situation at 2011 September 9British
Antarctic Survey Ozone Bulletin
The ozone hole began to form in mid
August, and by early September had reached an area of 22 million square
kilometres, a little larger than the average for the last decade. Ozone
depletion is now widespread over Antarctica. Minimum values within the polar
vortex are below 200 DU. The circum-polar ozone belt outside the vortex is
intensifying, with some areas above 400 DU. The lower stratospheric temperature
is near its winter minimum, with much of the Antarctic ozone layer below the
polar stratospheric cloud formation temperature. This temperature is below the
normal for this time of year.
Situation at 2011 September 5
British Antarctic Survey Ozone Bulletin Ozone depletion is now
widespread over Antarctica. Minimum values within the polar vortex are below 200
DU. The circum-polar ozone belt outside the vortex is intensifying, with some
areas above 400 DU. The lower stratospheric temperature is near its winter
minimum, with much of the Antarctic ozone layer below the polar stratospheric
cloud formation temperature. This temperature is below the normal for this time
of year.
Antarctic Ozone Bulletin No 1 / 2011 19 August 2011
WMO Antarctic Ozone Bulletin
The daily minimum temperatures at the 50 hPa level and south of 50°S have been
below the 1979-2010 average since April.
The average temperature over the 60-90°S region was quite close to or below the
long-term mean until the middle of July. A minor warming event in the middle of
July led to temperatures rising above the long-term mean for some days. During
August the 60-90°S mean temperature has decreased and is now well below the long
term average.
Since the onset of NAT temperatures on 10 May the NAT area has been above the
1979-2010 average during the whole winter. The NAT area reached peaks above 27
million km2 on a couple of occasions in August.
The longitudinally averaged heat flux between 45°S and 75°S is an indication of
how much the stratosphere is disturbed. From April to early July the 45-day mean
of the heat flux was lower than or close to the 1979-2010 average. In early
July, the heat flux increased somewhat in conjunction with the minor
stratospheric warming event and remained larger than the 1979-2010 average until
early August. The last few days the heat flux has been smaller than the
long-term average. This means that the vortex has been relatively stable so far
this year and more stable than in 2010.
At the altitude of ~18 km the vortex is now almost entirely depleted of
hydrochloric acid (HCl), one of the reservoir gases that can be transformed to
active chlorine. The polar vortex was somewhat less depleted of HCl in 2008 and
2010, as compared to 2009 and 2011. The area affected by HCl removal is somewhat
larger in 2011 than in the previous years.
In the sunlit collar along the vortex edge there are regions with 1.5-1.8 ppbv
of active chlorine (chlorine monoxide, ClO), and ozone depletion has just
started. The maximum mixing ratio of ClO is somewhat lower than in 2008 and 2009
but larger than in 2010 at the same date.
Satellite observations show that the area where total ozone is less than 220 DU
(“ozone hole area”) is normal compared to recent years. In mid-August, the ozone
hole area is larger than in 2008 and 2010 but smaller than in 2009. However, the
onset of ozone depletion varies considerably from one year to the next,
depending on the position of the polar vortex and availability of daylight after
the polar night.
Measurements with ground based instruments and with balloon sondes show first
signs of ozone depletion at some sites located close to the vortex edge. In this
issue data are reported from the following stations: Arrival Heights, Dôme
Concordia, Dumont d’Urville, Marambio, Neumayer, Rothera, Syowa and Vernadsky.
As the sun returns to Antarctica after the polar night, it is expected that
ozone destruction will speed up. It is still too early to give a definitive
statement about the development of this year’s ozone hole and the degree of
ozone loss that will occur. This will, to a large extent, depend on the
meteorological conditions. However, the temperature conditions and the extent of
polar stratospheric clouds so far this year indicate that the degree of ozone
loss will be about average in comparison to the ozone holes of the last decade.
WMO and the scientific community will use ozone observations from the ground,
from balloons and from satellites together with meteorological data to keep a
close eye on the development during the coming weeks and months.
Situation at 2011 August 18British
Antarctic Survey Ozone Bulletin
Ozone depletion is now becoming
widespread over Antarctica. Minimum values within the polar vortex are probably
below 200 DU, though this is not well reflected in the satellite analyses. The
circum-polar ozone belt outside the vortex is intensifying, with some areas
above 400 DU. The lower stratospheric temperature is nearing its winter minimum,
with much of the Antarctic ozone layer below the polar stratospheric cloud
formation temperature. This temperature is below the normal for this time of
year.
Situation at 2011 August 1British
Antarctic Survey Ozone Bulletin
Ozone depletion is now taking place
over Antarctica. Minimum values within the polar vortex are below 240 DU. The
circum-polar ozone belt outside the vortex is intensifying, with some areas
above 430 DU. The lower stratospheric temperature is nearing its winter minimum,
with much of the Antarctic ozone layer below the polar stratospheric cloud
formation temperature. This temperature is a little below the normal for this
time of year.
2011 the Year of Two Ozone Holes
Arctic Ozone
October 18
2011-Unusually Chilly
Stratosphere Behind 2011’s Record Arctic Ozone Hole
October 2
2011-NASA
Leads Study Of Unprecedented Arctic Ozone Loss
Nature Article
5 April
2011-Arctic
Ozone Loss 2011
Bad news after good? –Recent Arctic stratospheric ozone losses
Arctic Ozone Loss interview Paul Newman
July 2011
August 2011
September 2011
September 27, 2011-The Ozone Hole Reaches South
America
October 2011
October 20, 2011-NOAA, NASA: Significant ozone
hole remains over Antarctica
October 20-Ozone Depletion a
Bigger Deal Down Under
