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Marine Hydrophysical Institute of the National Academy of Sciences of UkraineThe work is supported by EU FP7 Project “ТHЕSEUS”E.N. Voskresenskaya, V.N. MaslovaLow-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? PDO AMO http://atmoz.org/blog/2008/05/14/timescale-of-the-pdo-nao-and-amo/
PDO • Moving Average = 9 yrs cyclones AMO
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. Composites of the frequency of cyclones associated with PDO phases 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)
Schematic representation of typical storm tracks for PDO phases PDO+ PDO-
AMO+ AMO- • Schematic representation of typical storm tracks for AMO phases
Frequency of cyclones in the Mediterranean-Black Sea region January • Shifts of North Atlantic storm tracks cause the deposition of zones with intensive cyclonic activity PDO- AMO+ PDO+ AMO-
MBS cyclones AMO- PDO+ AMO- PDO- AMO PDO 1948 1965 1976 1995 2000 2006
AMO- &PDO- AMO- &PDO+ Anomalies of 500hPa geopotential height (m) 1967 – 1971 1988 – 1992 January Frequency of cyclonic centers in 2.5×2.5° squares 1967 – 1971 1988 – 1992
ms-1 PDO+ AMO- PDO+ AMO- PDO+ AMO- PDO- AMO- • Schematic representation of typical storm tracks January • Composites of 500hPa wind vector • 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+ PDO- AMO+ PDO+ AMO PDO 1948 1965 1976 1995 2000 2006