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Takeaki Sampe, Hisashi Nakamura, Atsushi Goto, and Wataru Ohfuchi

the time averaging. The E–P flux is defined here as ( E y , E z ) = p / p s cos ϕ (− u ′ υ ′ , f υ ′ θ ′ /Θ z ), where p s (=1000 hPa) is the standard surface pressure and Θ z vertical derivative of potential temperature of the mean state ( Andrews and McIntyre 1976 ; Plumb 1986 ). The E–P flux represents the propagation of wave activity, and its direction is parallel to the group velocity of the wave. Effective forcing of U by eddies is proportional to ∇ · E in the transformed

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Bunmei Taguchi, Hisashi Nakamura, Masami Nonaka, and Shang-Ping Xie

these oceanic processes rather than by local atmospheric forcing, those SST anomalies in the KOE region accompany surface turbulent heat fluxes that can act as a thermal forcing on the overlying atmosphere ( Tanimoto et al. 2003 ; Nonaka et al. 2006 ). In fact, numerical experiments by Peng and Whitaker (1999) suggest that the SST anomaly in the KOE region may be able to force a basin-scale atmospheric response, although it may be sensitive to the background flow. Furthermore, observational

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Masanori Konda, Hiroshi Ichikawa, Hiroyuki Tomita, and Meghan F. Cronin

ABL to the north of the KE front and confines the large heat flux over the KE front in this condition. It is evident from Fig. 3 that the SHF makes a large contribution to the ocean surface cooling and in turn to the thermal forcing of the ABL. The Bowen ratio (defined by H / Q ) clearly shows that the energy balance in the ABL is quite different from that in the tropical ocean. The average of the Bowen ratio during period I (period II) was 0.55 (0.58) at JKEO, which is much larger than the

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Masami Nonaka, Hisashi Nakamura, Bunmei Taguchi, Nobumasa Komori, Akira Kuwano-Yoshida, and Koutarou Takaya

, 2006 ). Unlike the situation where SST anomalies are generated in response to basin-scale wind anomalies, the positive correlation is an indication of oceanic thermal forcing on the planetary boundary layer (PBL), especially in regions of strong ocean currents including midlatitude oceanic frontal zones. This is also supported by observed positive correlation between surface heat flux and SST anomalies (i.e., enhanced upward heat flux over positive SST anomalies) in the western North Pacific

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Shoshiro Minobe, Masato Miyashita, Akira Kuwano-Yoshida, Hiroki Tokinaga, and Shang-Ping Xie

1. Introduction How the midlatitude ocean influences the overlying atmosphere on climate time scales is a long-standing question. Namias (1969 , 1972) hypothesized that anomalies of extratropical sea surface temperature (SST) cause interannual and decadal persistency of atmospheric circulation anomalies. This basin-scale covariability between the atmosphere and ocean, however, is now generally recognized as being due to the atmospheric forcing onto the ocean via surface heat fluxes and Ekman

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James F. Booth, Lu Anne Thompson, Jérôme Patoux, Kathryn A. Kelly, and Suzanne Dickinson

the SST modifies the boundary layer winds along the Kuroshio Extension. Using QuikSCAT wind measurements, Chelton et al. (2004) show for all oceans that small-scale variability in the wind stress field is partially caused by SST anomalies and associated heat fluxes. This ocean–atmosphere forcing also occurs locally ( Sweet et al. 1981 ) and can be attributed to the coupling of the surface winds and the free-tropospheric winds because of the instability of the boundary layer ( Wallace et al. 1989

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Jeffrey Shaman, R. M. Samelson, and Eric Skyllingstad

cold wintertime Canadian air is advected over warm ocean waters. A recent modeling study shows that the combined effects of Rocky Mountain–like orography and land–sea temperature contrast synergistically concentrate synoptic activity around the latitude of the continental margin ( Gerber and Vallis 2009 ). In response to greenhouse gas forcing, many climate models project increasing extratropical storm activity. Over North America, the increased storm activity will likely organize in this region of

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