21
December 2006 British
Antarctic Survey Ozone Bulletin Ozone levels across
Antarctica dropped rapidly in September and were generally at their minimum in
early October. They have now risen above ozone hole limits, however a
significant area of the southern ocean south of Africa is still experiencing
ozone levels substantially below the normal, with a few areas approaching 40%
depletion. Lowest levels are currently near 240 DU over parts of the Southern
Ocean. Temperatures in the ozone layer are now near summer values, though values
remain below the mean of the last few decades. The ozone hole grew rapidly from
mid August and reached nearly 28 million square kilometres in size at the
equinox. The ozone hole was at record or near record size from mid September
until late November, when it began to decline rapidly. Although not an absolute
record in size it was a record for the amount of ozone destroyed. When the ozone
hole became more elliptical the edge of the ozone hole made passes over the tip
of South America and South Georgia and over the latter, uv levels reached
similar values to those seen at mid-day in the tropics.
06
December 2006 British
Antarctic Survey Ozone Bulletin
Ozone levels across
Antarctica dropped rapidly in September and were generally at their minimum in
early October. They have now risen above ozone hole limits at most locations,
however a large area is still experiencing ozone levels substantially below the
normal, with a few areas approaching 50% depletion. Lowest levels are currently
near 200 DU over parts of the Southern Ocean. The polar vortex is beginning to
collapse rapidly. Temperatures within it remain close to the minimum seen over
the last few decades, but are rising. The ozone hole grew rapidly from mid
August and reached nearly 28 million square kilometres in size at the equinox.
The ozone hole was at record or near record size from mid September until late
November, when it began to decline rapidly and is now around 3 million square
kilometres . Although not an absolute record in size it was a record for the
amount of ozone destroyed. When the ozone hole became more elliptical the edge
of the ozone hole made passes over the tip of South America and South Georgia
and over the latter, uv levels reached similar values to those seen at mid-day
in the tropics.
23
November 2006 British
Antarctic Survey Ozone Bulletin
Ozone levels across Antarctica dropped rapidly
in September and were generally at their minimum in early October; they are now
slowly rising at most locations. Lowest levels are currently near 200 DU over
parts of Antarctica. The polar vortex is shrinking, but remains significantly
larger than average for this time of year. Temperatures within it are generally
below the normal for the time of year, but are rising. The ozone hole grew
rapidly from mid August and reached nearly 28 million square kilometres in size
at the equinox. The ozone hole has been at record or near record size since mid
September. Although not an absolute record in size it was a record for the
amount of ozone destroyed. I t is now shrinking, although at around 13 million
square kilometres it is still a record size for mid November.
3
November 2006 British
Antarctic Survey Ozone Bulletin
Ozone levels across
Antarctica dropped rapidly in September and were generally at their minimum in
early October; they are now slowly rising at most locations. Lowest levels are
currently below 120 DU over parts of Antarctica. The polar vortex is shrinking,
but remains significantly larger than average for this time of year.
Temperatures within it are generally below the normal for the time of year, but
are rising. The ozone hole grew rapidly from mid August and reached nearly 28
million square kilometres in size at the equinox. It was the largest on record
for the week preceding the equinox, and although not an absolute record in size
it was a record for the amount of ozone destroyed. It is now shrinking, although
at around 15 million square kilometres it is near a record size for early
November. When the ozone hole becomes more elliptical the edge of the ozone hole
can makes passes over the tip of South America and South Georgia.
26
October 2006 British
Antarctic Survey Ozone Bulletin
Ozone
levels across Antarctica dropped rapidly in September and were at their minimum
in early October; they are now slowly rising at most locations. Lowest levels
are currently below 120 DU over parts of Antarctica. The polar vortex is
shrinking, but remains significantly larger than average for this time of year.
Temperatures within it are generally below the normal for the time of year. The
ozone hole grew rapidly from mid August and reached nearly 28 million square
kilometres in size at the equinox. It was the largest on record for the week
preceding the equinox, and although not an absolute record in size it was a
record for the amount of ozone destroyed. It is now shrinking, although at 19
million square kilometres it is at a record size for late October. The ozone
hole has become much more elliptical at times and the edge of the ozone hole
then makes passes over the tip of South America and South Georgia.
20
October2006 NASA and National Oceanic
and Atmospheric Administration (NOAA) scientists report this year's ozone hole
in the polar region of the Southern Hemisphere has broken records for area and
depth.
"From
September 21 to 30, the average area of the ozone hole was the largest ever
observed, at 10.6 million square miles," said Paul Newman, atmospheric
scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. If the
stratospheric weather conditions had been normal, the ozone hole would be
expected to reach a size of about 8.9 to 9.3 million square miles, about the
surface area of North America.
6
October2006 British
Antarctic Survey Ozone Bulletin
Ozone levels across
Antarctica dropped rapidly in September and are now near their minimum. Lowest
levels are currently near 100 DU over parts of Antarctica. The polar vortex is
shrinking, but remains significantly larger than average for this time of year.
Temperatures within it are generally below the normal for the time of year. The
ozone hole grew rapidly from mid August and reached nearly 28 million square
kilometres in size at the equinox. It was the largest on record for the week
preceding the equinox, although not an absolute record in size and it is now
shrinking. The ozone hole has become much more elliptical and the edge of the
ozone hole is making passes over the tip of South America. The next pass is
expected from October 7 to 10. It also crosses South Georgia and here the next
pass is expected from October 9 to 12.
3
October2006 World
Meteorological Organization This year’s hole in the Antarctic ozone layer
was the most serious on record exceeding that of 2000. Not only was it the
largest in surface area (matching 2000) but also suffered the most mass deficit,
meaning that there was less ozone over the Antarctic than ever previously
measured.
Measurements were taken from
instruments on both NASA and European Space Agency (ESA) satellites. These are
validated by surface based observations of the WMO Global Atmosphere Watch (GAW)
ozone network. Each agency uses different instruments hence the slightly
different values.
NASA instruments showed that,
on 25 September 2006, the area of the hole reached 29.5 million km2, compared to
29.4 million km2 reached in September 2000.
According
to ESA, the ozone hole area reached 28.0 million km2 on 25 September 2006, very
close to the maximum in 2000, which peaked at 28.4 million km2
The
ozone mass deficit in 2006 was measured at 39.8 megatonnes on 1 October, higher
than in 2000, which peaked at 39.6 megatonnes on 29 September. Mass deficit is
the amount of ozone missing from a vertical column of air compared to a baseline
measured many decades earlier before severe ozone depletion appeared. This year’s
hole was caused by the continuing presence of peak levels of ozone destroying
substances in the atmosphere combined with a particularly cold stratospheric
winter.
2 October 2006 European
Space Agency-Ozone
measurements made by ESA’s Envisat satellite have revealed the ozone loss of
40 million tonnes on 2 October 2006 has exceeded the record ozone loss of about
39 million tonnes for 2000.Full story click here
The ozone loss at 12:00 GMT of each day from GOME
(1996-2002) and SCIAMACHY (2003-2006) Assimilated Ozone Fields. The ozone loss
is the amount of ozone in megaton necessary to fill the ozone hole to 220 Dobson
units (DU) over the whole area. DU stands for the total thickness of ozone in a
given vertical column if it were concentrated into a single slab at standard
temperature and atmospheric pressure – 400 DUs is equivalent to a thickness of
four millimetres, for example. Credits: KNMI/TEMIS
The size of the Antarctic ozone hole at
12:00 GMT of each day from GOME (1996-2002) and SCIAMACHY (2003-2006)
Assimilated Ozone Fields. The size of the ozone hole is the area on the globe in
million square km of ozone column values below 220 Dobson units (DU). DU stands
for the total thickness of ozone in a given vertical column if it were
concentrated into a single slab at standard temperature and atmospheric pressure
– 400 DUs is equivalent to a thickness of four millimetres, for example.
Credits: KNMI/TEMIS
The depth of the Antarctic ozone hole at
12:00 GMT of each day from GOME (1996-2002) and SCIAMACHY (2003-2006)
Assimilated Ozone Fields. The depth of the ozone hole is the lowest ozone column
value in Dobson Units (DU) for latitudes below 30° South. DU stands for the
total thickness of ozone in a given vertical column if it were concentrated into
a single slab at standard temperature and atmospheric pressure – 400 DUs is
equivalent to a thickness of four millimetres, for example. Credits: KNMI/TEMIS
Situation at 2006 September
29 British
Antarctic Survey Ozone Bulletin
Ozone levels across
Antarctica have dropped rapidly since mid September. Lowest levels are
approaching 100 DU in parts of Antarctica. The polar vortex is a little larger
than it was at this time last year, although it is beginning to shrink.
Temperatures within it are generally below the normal for the time of year. The
ozone hole grew rapidly from mid August and reached nearly 28 million square
kilometres in size at the equinox. It was the largest on record for the week
preceding the equinox, although not an absolute record in size. The ozone
observing season at Vernadsky and Halley has commenced and both stations are
experiencing ozone hole levels. Rothera can make observations throughout the
year; here ozone values dropped rapidly in mid September and a minimum of 105 DU
was recorded. The edge of the ozone hole is expected to swing over the tip of
South America around October 4. A prediction made at the SCAR conference in
Hobart in July suggested that the 2006 ozone hole is likely to be one of the
larger and deeper ones (perhaps 28 million square kilometres), based on a
correlation with the 100 hPa temperature. [This prediction is clearly
confirmed.] Adrian Tuck predicts a significant spring warming before mid
October. Note: The Antarctic ozone hole is usually largest in early September
and deepest in late September to early October. September 16 is world ozone day.
Prior to the formation of ozone holes, Antarctic ozone values were normally at
their lowest in the autumn (ie March).
Situation at 2006 September
22-WMO Bulletin-Since
the last Bulletin (12 September) vortex minimum temperatures at 50 hPa continue
to remain around 181-182 K, which is well below the frost point and colder than
for any year in the 1979-2005 period for this time of the year. The average
temperature in the 60-90°S region has increased slightly, from 193 K to 194 K,
but is lower than any other year since 1979 for this time of the year. The area
where temperatures are low enough for existence of polar stratospheric clouds of
type I (NAT) at the 450 K isentropic level (~17 km or ~70 hPa), has continued to
decline from its peak (28.9 million km2) in late July to about 21 million km2 on
18 September. Since early July, the south polar vortex has been larger than the
1996-2005 average at the 450, 550 and 650 K isentropic levels. At 450 K, the
vortex area has on certain days been as large as the maximum for the 1986-2005
time period. Chlorine activation reached its peak around 1 September and is now
declining. There is still a region inside the vortex where hydrochloric acid (HCl)
is completely depleted, which is an indication of complete activation.
Ozonesonde observations show up to 90% ozone loss in the 15-20 km altitude range
by 20 September compared to early August. The area where total ozone is less
than 220 DU (also called the "ozone hole area") was relatively small
until around 20 August. Since then the ozone hole area has increased more
rapidly than the 1979-2005 average and is now close to 28 million km2, which is
more than the maximum reached in 2005 (26 million km2) and very close to the
maximum reached in 2003. It is still somewhat lower than the ozone hole area in
2000, which peaked at 28.5 million km2 on 10 September. Measurements of total
ozone at individual stations and total ozone maps synthesised by the World Ozone
and UV Data Centre show that total ozone columns in August and the first half of
September were somewhat larger in 2006 as compared to the same time of the year
in 2005. The last few days, ozone columns at most stations have dropped rapidly
and are now the same as at the same time in 2005. Minimum total ozone columns
from satellite observations have dropped rapidly the last days and are now near
and even below the values observed in 2005. Predictions based on meteorological
forecasts indicate that the vortex will remain relatively concentric and
unperturbed, and it is not likely that areas outside Antarctica will be
significantly affected by the ozone hole between now and 30 September. The
intensity of ultraviolet radiation remains modest, with UV indices not exceeding
3.1 in southern Chile and Antarctica. As ozone depletion continues and the solar
elevation increases, UV indices are expected to increase. 0 2 4 6 8 10 12 14
Ozone partial pressure [mPa] Ozone soundings from the Argentinian GAW station
Belgrano (78°S, 35°W). One can see the progression of ozone depletion from 2
August until 20 September. In the height region most affected by ozone
destruction, the depletion amounts to about 80%. The ozone hole is expected to
deepen further over the next couple of weeks. The soundings are carried out as a
collaboration between Argentinian researchers and scientists from the Spanish
Instituto Nacional de Tecnica Aeroespacial (INTA). Global Atmosphere Watch
Situation at 2006 September
16 British
Antarctic Survey Ozone Bulletin
Ozone levels across
Antarctica have dropped rapidly in the last week. Lowest levels are now below
150 DU across a large part of Antarctica. The polar vortex is a little larger
than it was at this time last year. Temperatures within it are generally below
the normal for the time of year. The ozone hole grew rapidly from mid August and
reached some 26 million square kilometres in size in mid September, one of the
largest areas on record for this time in September.
Situation at 2006 September
14 British
Antarctic Survey Ozone Bulletin
Ozone levels across
the polar vortex are falling, with lowest levels in the edge region, whilst the
circumpolar high is building. The polar vortex is a little larger than it was at
this time last year. Temperatures within it are generally below the normal for
the time of year. The ozone hole grew rapidly from mid August and peaked at some
24 million square kilometres in size in early September, comparable to the hole
in 2005.
Situation at 2006 September
1
British
Antarctic Survey Ozone Bulletin
Ozone levels in the
sunlit edge region of the polar vortex are falling and are lowest here, whilst
the circumpolar high is building. The polar vortex is a little larger than it
was at this time last year. Ozone levels in the centre of the vortex are not far
from normal as this area is still in darkness. The ozone hole has grown rapidly
since mid August and is now some 23 million square kilometres in size,
comparable to the hole in 2005.
Situation at 2006 August 17
British
Antarctic Survey Ozone Bulletin
Ozone levels in the
sunlit edge region of the polar vortex are falling, whilst the circumpolar high
is building. The polar vortex is a little larger than it was at this time last
year. The ozone observing season at Vernadsky has commenced, whilst that at
Halley commences in late August. Rothera can make observations throughout the
year; here ozone values have dropped to ozone hole levels.
Situation at 2006 August 2
British
Antarctic Survey Ozone Bulletin
Ozone levels in the
sunlit edge region of the polar vortex are beginning to fall. The ozone
observing season at Vernadsky will soon commence, whilst that at Halley
commences in late August. Rothera can make observations throughout the year;
here ozone values are near ozone hole levels. Andrew Klekociuk of the Australian
Antarctic Division predicts that the 2006 ozone hole is likely to be one of the
larger and deeper ones (perhaps 28 million square kilometres), based on a
correlation with the 100 hPa temperature. Adrian Tuck predicts a significant
spring warming before mid October. Note: The Antarctic ozone hole is usually
largest in early September and deepest in late September to early October.
September 16 is world ozone day. Prior to the formation of ozone holes,
Antarctic ozone values were normally at their lowest in the autumn (ie March).
Situation at 2006 May 5British
Antarctic Survey Ozone Bulletin Generally Antarctic
ozone levels are past their autumn minimum, but the polar vortex is
spinning up giving a range between 250 DU and 350 DU across the
continent.
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