Marine Hydrophysical Institute of the National Academy of Sciences of Ukraine
The work is supported by EU FP7 Project “ТHЕSEUS”
E.N. Voskresenskaya, V.N. Maslova
Low-frequency anomalies of cyclonic activity in the Mediterranean-Black Sea region associated with ocean-atmosphere interaction in the North Atlantic and North Pacific
10th European Conference on Applications of Meteorology (ECAM)12 – 16 September 2011Berlin, Germany
Climate shift or low-frequency variability?
http://atmoz.org/blog/2008/05/14/timescale-of-the-pdo-nao-and-amo/
AMO PDO
Winter frequency anomalies (Black Sea cyclones)
-1,5
-1
-0,5
0
0,5
1
1,5
2
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
Winter PDO index
-1
-0,5
0
0,5
1
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
Winter AMO index
-0,3
-0,2
-0,1
0
0,1
0,2
0,3
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
Moving Average = 9 yrs
PDO
AMO
cyclones
Composites of the frequency of cyclones associated with PDO phases
Voskresenskaya, E. N. and Maslova, V. N. : Winter-spring cyclonic variability in the Mediterranean-Black Sea region associated with global processes in the ocean-atmosphere system. Adv. Sci. Res., 6, 237–243, 2011.
0
0,1
0,2
0,3
0,4
1 2 3 4 5 6 7 8 9 10 11 12
Freq
uenc
y
0
0,1
0,2
0,3
0,4
1 2 3 4 5 6 7 8 9 10 11 12
Freq
uenc
y
0
0,1
0,2
0,3
0,4
1 2 3 4 5 6 7 8 9 10 11 12
Months
Fre
quen
cy
1948-1976 (PDO-)
1977-2001 (PDO+)
Black Sea Western Mediterranean Eastern Mediterranean
Data and methods NCEP/NCAR reanalysis data sets on
1000hPa geopotential height in 1948 – 2006 for cyclone detection and their characteristics calculation with the use of special methodology after Bardin (1995)
interactive site of NOAA/ESRL Physical Sciences Division for analysis of Monthly/Seasonal Climate Composites
Atlas of extratropical storm tracks from NASA GISS web page
Aim
to study winter cyclonic activity in the Mediterranean-Black Sea region associated with the Atlantic multidecadal oscillation (AMO) and Pacific decadal oscillation (PDO)
How do PDO & AMO manifest in North Atlantic
storm tracks?
PDO-
PDO+
Schematic representation of typical storm tracks for PDO phases
AMO-
AMO+
Schematic representation of typical storm tracks for AMO phases
Frequency of cyclones in the Mediterranean-Black Sea region
Shifts of North Atlantic storm tracks cause the deposition of zones with intensive cyclonic activity
PDO-
PDO+
AMO+
AMO-
January
What are the joint AMO&PDO manifestations?
+ + + + + + + + + - - - - + + + + + +
- - - - - - - - - + + + + + + + - - -
AMO
PDOAMO-PDO-
AMO-PDO+
1948 1965 1976 1995 2000 2006
MBS cyclones
AMOAMO- - && PDOPDO++AMOAMO- - && PDOPDO--
Frequency of cyclonic centers in 2.5×2.5° squares
Anomalies of 500hPa geopotential height (m)
1967 – 1971 1988 – 1992
1967 – 1971 1988 – 1992
January
Composites of 500hPa wind vector
PDO-AMO-
PDO+AMO-
PDO+AMO-
ms-1
PDO+AMO-
Schematic representation of typical storm tracks
January
Cyclonic activity in the Mediterranean-Black Sea region is more intense for combination AMO-&PDO- than for PDO+&AMO-
Results AMO and PDO have significant manifestations
in decadal-multidecadal variability of cyclonic activity in the Mediterranean-Black Sea region due to specific shifts of North Atlantic storm tracks.
combination of negative AMO and PDO phases is accompanied by intensification of cyclonic activity in the Mediterranean-Black Sea region.
combination of the positive PDO phase and negative AMO phase causes the weakening of cyclonic activity in the studied region.
Next steps
To study other combinations of the AMO&PDO phases and mechanisms of their influence on cyclonic activity in the Mediterranean-Black Sea region
+ + + + - - - - - - - - - - - - - - + +
- - - - - - - - - - + + + + + + + + - -
AMO
PDOAMO+PDO-
AMO+PDO+
1948 1965 1976 1995 2000 2006
