Quasi-stationary planetary wave long-term

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16 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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Quasi
-
stationary planetary wave long
-
term
changes in total ozone over Antarctica and
Arctic





A.Grytsai
,

O
.Evtushevsky,
O. Agapitov,


A.Klekociuk, V.Lozitsky,
G. Milinevsky




gennadim@gmail.com
,
Andrew.Klekociuk@aad.gov.au


National Taras Shevchenk
o

University

of Kyiv, Ukraine

Australian Government Antarctic Division, Hobart, Australia

Research in the framework of SCAR ICESTAR Program

Task:

Analysis of interannual and decadal changes of the
quasi
-
stationary wave amplitude and structure of zonal
extremes are analyzed using the TOMS satellite data.
Comparison to Northern Hemisphere

Time interval
: 1979
-
2005.

Season:

the spring months September
-
November.

Analysis method:

zonal wave parameters determination
using longitudinal distribution of the total ozone at
individual latitude circles within 50

S
-
80

S.

Dataset:

TOMS measurements of total ozone content

Regular satellite measurements of total ozone content (TOC) have been
carried out using TOMS (Total Ozone Mapping Spectrometer) since

1978 (
with a gap in

1993
-
9
5
).
Spatial resolution is equal

1
°

on latitude
and

1.25
°

on longitude
.

Akademik Vernadsky

Total ozone distribution on

1.10.1979
and

1.10.2004

http://toms.gsfc.nasa.gov

Traveling wave from ground
-
based
observations.

Planetary waves in total ozone

Total ozone distribution to the south
of 30

S,
25.09.2001
. Dashed line
marks the latitude circle 65

S.

Time
-
longitude distribution of total ozone
in the Southern Hemisphere spring

Zonal wave in total
ozone is presented by
quasi
-
stationary
maximum

corresponded to mid
-
latitude air and
minimum
, which is
caused by ozone hole
displacement and
elongation.

Traveling planetary
waves are seen as
inclined strips.

September
-
November
1996
,
55
°
S
-
75
°
S

50
°
S

55
°
S

60
°
S

70
°
S

65
°
S

Structure of ozone zonal asymmetry

October

mean

total

ozone

over

the

southern

latitudes

40

S
-
90

S

by

the

TOMS

data
.

The

dashed

circle

marks

the

Vernadsky

Station

latitude

65

S
.

Two ozone anomalies in
Southern Hemisphere:

low ozone (

200 DU) in
ozone hole and

high ozone (

400 DU)
in
mid
-
latitude band.


Monthly mean

longitudinal
distributions of the total ozone by the
TOMS data for

(a) the 9 months of the southern
summer, autumn and winter 2005 at
60

S;

(b) the spring months September,
October and November 2005 at 60

S.

Increasing of ozone
asymmetry in spring

Interannual variations of quasi
-
stationary wave in total
ozone during 1979
-
2005 on different latitudes
50
°
S
-
80
°
S

The 3
-
month mean longitudinal distributions of total ozone at
the seven latitude circles within 50
°
S
-
80
°
S



Trends in the quasi
-
stationary wave
maximum

and
minimum


Different trends in the
regions of zonal maximum
and minimum cause long
-
term increase of wave
amplitude.


Lower trend values at the
wave maximum is due to
mid
-
latitude origin of
stratospheric air, whereas
the higher trends at wave
minimum is result of polar
air penetration to this
region.

-
23 DU/decade


-
38 DU/decade

-
12 DU/decade


-
15 DU/decade

55
°
S

65
°

S

Amplitude of quasi
-
stationary temperature
wave

Interannual variations of the August
-
mean
amplitude of quasi
-
stationary wave in the
100
-
hPa temperature, NCEP
-
NCAR
reanalysis data 1979
-
2005.

Large amplitude of
stationary wave in the
lower stratosphere
temperature in August
2002 preceded the large
stratospheric warming in
September 2002.

The event 1988 shows
also anomalously high
amplitude but at middle
latitude only.

50 55 60 65 70 75

A
m
p
l
i
t
u
d
e
,

K
Southern latitude
Geographical position of zonal extremes
in total ozone

T
he

average

positions

of

the

quasi
-
stationary

extremes

in

September
-
November

1979
-
2005

(left)

and

the

5
-
year

means

for

1979
-
1983

and

2001
-
2005

(right)
.


Minima

are

located

along

Antarctic

Peninsula

in

average

data

of

1973
-
1983

and

shift

eastward

during

last

decades
.


Shift

distance

is

about

45

,

or



2000

km

at

65


S
.


Long
-
term change in temperature fields



The 5
-
year mean eddy
tropopause temperature
(left) and

eddy temperature at the
100
-
hPa pressure level
(right)

for 1979
-
1983 (top) and
2001
-
2005 (bottom)

by NCEP
-
NCAR
reanalysis data.

Eastward shift of about 30


is observed in the region of zonal minimum
and the position of zonal maximum is almost unchanged.



(a) Spring mean distribution of total ozone
(September
-
November) and (b) its deviation
from zonal mean averaged over 1979
-
2005.
TOMS data were used.

(a)

(b)

Total ozone and tropopause
pressure for spring 1979
-
2005

(c)

(c) Zonal asymmetry in tropopause pressure
during spring 2005, NCEP
-
NCAR reanalysis
data.

SON
2005


SON 1979
-
2005


SON 1979
-
2005





The highest asymmetry along meridians 45W
-
135E exists, that
corresponds in general to the longitudes of ozone extremes. These data
confirm
reverse relation between total ozone and tropopause height.

Tropopause height decreases monotonically between 15.5 km and 9.5 km
(i.e. by about 4 km) over Antarctica in October 2005.


Tropopause zonal asymmetry

Meridian profiles of tropopause pressure over Southern
Hemisphere in October 2005, NCEP
-
NCAR reanalysis data.

Over

the

Arctic

region

ozone

distribution

is

dislike

to

Southern

Hemisphere’s

one
.

During

spring

ozone

maximum

is

observed

in

the

middle

and

high

Northern

latitudes
.

The

lowest

values

are

registered

in

the

autumn

months,

but

they

are

significantly

larger,

than

into

southern

ozone

hole
.

Wave

structure

is

complicated

without

wave

1

domination
.

Northern Hemisphere

Northern Hemisphere




Ozone

values

at

60
N

are

higher

comparatively

with

the

ones

in

the

edge

region

of

southern

ozone

hole

in

the

corresponding

time

period

(early

spring)
.

But

from

the

1990
s

low

total

ozone

levels

have

been

observed

in

the

Greenwich

longitudinal

sector

approximately
.

Wave

1

with

the

quasi
-
stationary

maximum

and

minimum

exists

during

considered

months
.


1
.
During the last 27 years amplitude of quasi
-
stationary
wave in total ozone in Antarctic spring increased with
maximal amplitude value and its trend at the latitude
65
°
S.

2.
The long
-
term eastward displacement of quasi
-
stationary
minimum is observed over the sector 60
°
W
-
0
°
E, whereas
the maximum takes enough stable position in the quadrant
90
°
E
-
180
°
E.

3.
Spatial distribution of tropopause height exhibits zonal
asymmetry structure and long
-
term tendency which are
similar to total ozone ones.

4. Ozone values in the Northern hemisphere high latitudes
are larger than in the Southern hemisphere, but their
negative trend exists as well.

Conclusion
-

1

Conclusion
-

2

5. Pre
-
ozone hole condition have been observed over North
Pole in the last 10
-
15 years.

6. Quasi
-
stationary wave 1 prevails in the southern ozone
hole edge region during spring. In the Northern hemisphere
high latitudes wave 1 affects ozone distribution.

7. Northern minimum is observed during autumn and
southern low values appear in the second part of winter.
Wave activity in the Northern hemisphere corresponds to
large ozone levels.

Intercomparison of ozone dynamics in Northern and Southern
Hemispheres will allow to study the similarities and differences in ozone
structure, connections, and separate the impact to ozone dynamics of
the underlying Earth (sea) surface and planetary wave activity.

This research was partly made in the framework of SCAR ICESTAR Program, was supported by
National Taras Shevchenko University of Kyiv, project 06BF051
-
12, by Grant of Ministry
Education and Science of Ukraine: Greece
-
Ukraine M/86
-
2006, and Australian Antarctic Science
project 737.