WP5.2: Variations in the precipitation component of the water cycle in the Mediterranean region Simon Krichak (TAU). The role of NAO. Monthly Mediterranean precipitation is affected by the main teleconnection regimes (NAO, EA/WR , ENSO, etc.) acting over Europe.
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WP5.2: Variations in the precipitation component of the water cycle in the Mediterranean region
Simon Krichak (TAU)
The role of NAO
Monthly Mediterranean precipitation is
affected by the main teleconnection regimes
(NAO, EA/WR , ENSO, etc.) acting over Europe.
It is also strongly influenced by the variations in
the positioning and intensity of upper troposphere
jets, PV streamers, coherent tropopause
disturbances as well as air moisture transport
all these factors are sensitive to the effects of
topography of the region.
The role of PV anomalies at the tropopause
(coherent tropopause disturbances and PV streamers)
Israeli floods of 3-4 December 2001
.- Krichak, S.O., P. Alpert and M. Dayan (2004) Role of atmospheric processes associated with hurricane Olga in December 2001 flash floods in Israel. J. Hydrometeorol., vol. 5, no. 6. pp. 1259-1270.
- Krichak, S.O., P. Alpert, M. Dayan, (2007) A southeastern Mediterranean PV streamer and its role in December 2001 case with torrential rains in Israel, Nat. Hazards Earth Syst. Sci., 7, 1-12.
- Krichak,S.O., P. Alpert, K. Bassat, P. Kunin (2007) The surface climatology obtained in a three-member ensemble simulation of the present-day (1961-1990) climate of the eastern Mediterranean region, Advances in Geosciences (ADGEO), (submitted).
Another extreme event of the same period in the Atlantic
Tropical – extratropical storm – hurricane Olga
hurricane since 12:00 UTC Nov. 26; peak intensity at 06:00 UTC Nov. 27, 2001
- relative vorticity in isentropic coordinates
Minus sign: makes PV positive since pressure decreases upward
f – planetary vorticity
PV - absolute vorticity times static stability
Coherent tropopause disturbance
Eastward propagation of the CTD is associated with advection of positive PV in lower troposphere
WNDT – deep layer wind shear i.e. wind at DT minus wind at 700 hPa
Strong WNDT zones indicate areas with intense convection
PV - streamer
PV - streamer
This WP is devoted to the understanding of the synoptic (physical) nature of the relations between the "secondary" factors listed and the variations in precipitation intensity over the region.
First, the jets influence the direction of synoptic scale features (also affected by topography).
Second, jets contribute to formation of upper level divergence and convergence zones.
Thirdly, they can influence moisture transport.
Finally, the jets can influence stability and be responsible for the (usually affected by topography) gravity wave formation.
It is expected that these relationships will also be changed with the global warming. We will thus provide a comprehensive image of the Mediterranean precipitation for both current climate and future climate.
(1) identification and analysis of the factors influencing the western Mediterranean precipitation (Task 5.2.1);
(2) identification and analysis of the factors influencing the eastern Mediterranean precipitation (Task 5.2.2);
Organization of strong cooperation with RL6 (and in particular WP6.3 [Ricardo Trigo]) will be important
This WP is also in strong interaction with other RLs of the CIRCE by using the data from global and regional climate modeling (links to RL1, RL2, RL4, RL5 and RL6).
Correct version of July 27 2006
Mistake in final (March 2007) version