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Philippe Peyrillé and Jean-Philippe Lafore

mechanisms and couplings involved in the WAM. For instance, PLR07 have shown how the Mediterranean Sea can efficiently modulate the WAM northward penetration and precipitation over the Sahel during the WAM season. Nevertheless this idealized approach presents some drawbacks due to severe assumptions such as no interaction with midlatitudes (wall-type lateral boundary conditions imposed to the north and south) and the zonal symmetry hypothesis over West Africa, which neglect planetary zonal waves and

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Christoph Schär and Nico Kröner

drivers behind the Mediterranean amplification of climate change. This term describes the fact that most climate models project an amplified warming and drying over southern Europe (see section 3 for further details). The alternative factor separation approach will be referred to as sequential factor separation (SFS). It is not as precise and general as the approach of Stein and Alpert (1993) , but it has advantages when n = 3 or more factors are considered, as it requires merely 2 n simulations

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Agnieszka A. Mrowiec, Stephen T. Garner, and Olivier M. Pauluis

polar lows results from the large temperature difference between the two fluids rather than from the subsaturation of the air at the surface ( Emanuel 1988b ). In extreme cases, they have hurricane-strength winds and bring significant precipitation. Another interesting example of hurricane-like vortices is “medicanes,” the large cyclonic storms that develop over the Mediterranean Sea. Observations show ( Fita et al. 2007 ) that these have near-hurricane magnitude and structure but tend to live only

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R. Krishnan, Vinay Kumar, M. Sugi, and J. Yoshimura

,b is the anomalous cyclonic circulation over the midlatitude region located to the east of the Caspian Sea. This cyclonic anomaly, embedded in the westerly winds, has a fairly extended horizontal scale stretching from the Mediterranean region up to about 85°E. It is important to note that the anomalous westerlies over WCA extend considerably southward and intrude into the Indo-Pak region and north central India. Furthermore, the midlatitude cyclonic anomaly has an equivalent barotropic structure

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J. Shpund, A. Khain, and D. Rosenfeld

accuracy in forecasting a TC intensity lies in the shortcomings of TC–ocean interaction descriptions ( Emanuel 1989 , 2003 ; Gall et al. 2008 ; Li 2004 ; Perrie et al. 2005 ; Wang et al. 2001 ). An important component of the TC–ocean interaction is sea spray generation within the surface layer at strong winds. A wide spectrum of sea spray particles (SSP) is generated during wave-breaking events—the size range of sea spray droplets can range from ~0.01 to ~600 μ m ( Clarke et al. 2006 ; Fairall

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Isla R. Simpson, Tiffany A. Shaw, and Richard Seager

metrics of the climatological zonal-mean or basin-mean jet location (e.g., Fyfe and Saenko 2006 ; Kidston and Gerber 2010 ; Swart and Fyfe 2012 ; Wilcox et al. 2012 ; Woollings and Blackburn 2012 ; Barnes and Polvani 2013 ; Bracegirdle et al. 2013 ), 2) methods based on the projection of zonal wind or sea level pressure anomalies onto the dominant modes of variability (e.g., the northern or southern annular modes) (e.g., Miller et al. 2006 ; Previdi and Liepert 2007 ; Woollings and Blackburn

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Urs Aebischer and Christoph Schär

-air outbreak into the western Mediterranean Sea, and the formation of a cyclone in the 850-hPa geopotential ( Fig. 4c ). Initially isolated centers of the cyclone are visible in the geopotential on both sides of the Alps, suggesting that the cyclone is approximately centered over the main ridge. By 0000 UTC 6 December, the low-level cyclone to the south of the Alps has intensified and has moved eastward toward the Adriatic Sea ( Fig. 4e ). To the rear of the cyclone there is strong northerly flow past the

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T. N. Krishnamurti, A. Thomas, Anu Simon, and Vinay Kumar

the IOD index and summer monsoon rainfall relationship during recent decades are illustrated in this paper. Overall the impression one gets from these indices is that no single parameter is a robust indicator of the seasonal rainfall behavior. Another observed feature is the northward arrival of a high sea level pressure anomaly extending from south of India northward to around 25°N latitude ( Krishnan et al. 2000 ). This northward-moving feature has been identified as a component of the

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Mark J. Rodwell

, and full GCM experiments to substantiate the proposed mechanism. Figure 1 shows the June to August time-mean 850-hPa winds calculated using analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF) for the years 1992–95, inclusive. There are generally easterlies over the tropical southern Indian Ocean, cross-equatorial flow at the east coast of Africa, and westerlies over the Arabian Sea and into India. These westerlies carry much of the moisture that sustains the monsoon

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Richard J. Reed

inferred that important heating also occursover major inland bodies of water such as the Mediterranean Sea, the Baltic, the Black Sea, the CaspianSea, the Great Lakes and, during November, overHudson Bay (Burbidge, 1951).Statistical data compiled by Petterssen (1950) giveevidence that the behavior pattern of cyclones isinfluenced by nonadiabatic heating in the abovementioned areas. For example, charts of the frequencyof occurrence of cyclogenesis show distinct maxima inwinter in all of these regions

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