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1. Introduction Recent studies have shown that air–sea flux variability associated with oceanic small-scale features such as mesoscale eddies has a different character from that associated with broader basin scales. Much attention has been paid to the air–sea momentum flux variability ( Xie et al. 1998 ; Chelton et al. 2001 ; Small et al. 2008 ; Schneider and Qiu 2015 ) but less to the air–sea turbulent heat flux variability. Air passing over the relatively strong gradients of sea surface
1. Introduction Recent studies have shown that air–sea flux variability associated with oceanic small-scale features such as mesoscale eddies has a different character from that associated with broader basin scales. Much attention has been paid to the air–sea momentum flux variability ( Xie et al. 1998 ; Chelton et al. 2001 ; Small et al. 2008 ; Schneider and Qiu 2015 ) but less to the air–sea turbulent heat flux variability. Air passing over the relatively strong gradients of sea surface
1. Introduction In the extratropical North Pacific, vigorous heat related to the turbulent heat flux (THF; the sum of the sensible and latent heat fluxes) is released from the ocean to the atmosphere in winter ( Fig. 1a ). The THF release in winter is predominantly controlled by surface wind, which has a negative local correlation with sea surface temperature (SST) ( Davis 1976 ; Frankignoul 1985 ; Iwasaka et al. 1987 ; Wallace and Jiang 1987 ; Lau and Nath 1994 ; Nakamura et al. 1997
1. Introduction In the extratropical North Pacific, vigorous heat related to the turbulent heat flux (THF; the sum of the sensible and latent heat fluxes) is released from the ocean to the atmosphere in winter ( Fig. 1a ). The THF release in winter is predominantly controlled by surface wind, which has a negative local correlation with sea surface temperature (SST) ( Davis 1976 ; Frankignoul 1985 ; Iwasaka et al. 1987 ; Wallace and Jiang 1987 ; Lau and Nath 1994 ; Nakamura et al. 1997
ocean hands over most of the heat to the atmosphere. The ocean-to-atmosphere heat transfer is concentrated near the western boundary current (WBC) region [i.e., the Gulf Stream (GS) and Kuroshio–Oyashio Extension (KOE)], which is signified by the largest ocean-to-atmosphere heat fluxes in the globe in the annual-mean sense as well as for the interannual variability. Another important contrast between the ocean and atmosphere is the very different role of mean circulations and eddies. In the ocean
ocean hands over most of the heat to the atmosphere. The ocean-to-atmosphere heat transfer is concentrated near the western boundary current (WBC) region [i.e., the Gulf Stream (GS) and Kuroshio–Oyashio Extension (KOE)], which is signified by the largest ocean-to-atmosphere heat fluxes in the globe in the annual-mean sense as well as for the interannual variability. Another important contrast between the ocean and atmosphere is the very different role of mean circulations and eddies. In the ocean
1. Introduction The crucial role of air–sea heat exchange in the global energy cycle demands a physical understanding and sound interpretation of the distribution of surface sensible and latent heat fluxes. Because the climatological-mean fluxes are well described using time-mean fields in the bulk flux formulas ( Simmonds and Dix 1989 ), many studies employ stationary and linear thinking to describe the response to sea surface temperature (SST) anomalies and fronts in the low latitudes
1. Introduction The crucial role of air–sea heat exchange in the global energy cycle demands a physical understanding and sound interpretation of the distribution of surface sensible and latent heat fluxes. Because the climatological-mean fluxes are well described using time-mean fields in the bulk flux formulas ( Simmonds and Dix 1989 ), many studies employ stationary and linear thinking to describe the response to sea surface temperature (SST) anomalies and fronts in the low latitudes
; Whitaker et al. 1988 ; Schultz 2001 ). Booth et al. (2012) examined the roles of the WCB in a cyclone’s growth and investigated how surface moisture and heat fluxes influence the development of extratropical cyclones in the Gulf Stream region. They postulated that the surface moisture and heat supply under the warm sector produces increased latent heating in the cyclones via the WCB, thereby strengthening the extratropical cyclogenesis. Another view is the active role of the CCB in the rapid
; Whitaker et al. 1988 ; Schultz 2001 ). Booth et al. (2012) examined the roles of the WCB in a cyclone’s growth and investigated how surface moisture and heat fluxes influence the development of extratropical cyclones in the Gulf Stream region. They postulated that the surface moisture and heat supply under the warm sector produces increased latent heating in the cyclones via the WCB, thereby strengthening the extratropical cyclogenesis. Another view is the active role of the CCB in the rapid
thermodynamic feedbacks between surface heat fluxes and ocean mixed layer temperature act to reduce thermal damping, enhancing low-frequency variability of the atmosphere, and 2) a nonlinear mechanism where an eddy-mediated process links SST forcing to storm track activity. The former can be considered as a passive coupling between the atmosphere and ocean and can be understood as an extension of Hasselmann climate model ( Hasselmann 1976 ) in the framework of a coupled atmospheric energy balance model and
thermodynamic feedbacks between surface heat fluxes and ocean mixed layer temperature act to reduce thermal damping, enhancing low-frequency variability of the atmosphere, and 2) a nonlinear mechanism where an eddy-mediated process links SST forcing to storm track activity. The former can be considered as a passive coupling between the atmosphere and ocean and can be understood as an extension of Hasselmann climate model ( Hasselmann 1976 ) in the framework of a coupled atmospheric energy balance model and
1986—in terms of atmospheric circulation fields and surface heat fluxes from the ocean. They revealed that surface energy fluxes from the Kuroshio/Kuroshio Extension under the updraft region of the cyclones were better maintained for the explosive cyclone than for the nonexplosive cyclone during its development stages. Takayabu et al. (1996) also pointed out that the energy supply from the Kuroshio/Kuroshio Extension is an important factor in the rapid intensification of extratropical cyclones
1986—in terms of atmospheric circulation fields and surface heat fluxes from the ocean. They revealed that surface energy fluxes from the Kuroshio/Kuroshio Extension under the updraft region of the cyclones were better maintained for the explosive cyclone than for the nonexplosive cyclone during its development stages. Takayabu et al. (1996) also pointed out that the energy supply from the Kuroshio/Kuroshio Extension is an important factor in the rapid intensification of extratropical cyclones
stochastic BB98 coupled system by Wu et al. (2006) , Zhang (2017) , and Bishop et al. (2017) . As explained by Zhang (2017) , it is important to include both ocean damping terms and ocean noise in the stochastic framework, and Bishop et al. (2017) show that this gives rise to the observed positive covariability of ocean temperature and air–sea heat flux (out of ocean) in ocean-eddying regions, such as the western boundary currents and Antarctic Circumpolar Current (ACC). These are regions where
stochastic BB98 coupled system by Wu et al. (2006) , Zhang (2017) , and Bishop et al. (2017) . As explained by Zhang (2017) , it is important to include both ocean damping terms and ocean noise in the stochastic framework, and Bishop et al. (2017) show that this gives rise to the observed positive covariability of ocean temperature and air–sea heat flux (out of ocean) in ocean-eddying regions, such as the western boundary currents and Antarctic Circumpolar Current (ACC). These are regions where
dominated by geostrophic advection, with a clear signature in SST. Sugimoto and Hanawa (2011) showed that SST changes are primarily responsible for turbulent heat flux variations. Because of the strong ocean-to-atmosphere fluxes of heat and moisture, the KOE is a region of large cyclogenesis, as major storm tracks are organized along or just downstream of the main oceanic frontal zones ( Hoskins and Hodges 2002 ; Bengtsson et al. 2006 ). Nakamura et al. (2004) and Taguchi et al. (2009) have
dominated by geostrophic advection, with a clear signature in SST. Sugimoto and Hanawa (2011) showed that SST changes are primarily responsible for turbulent heat flux variations. Because of the strong ocean-to-atmosphere fluxes of heat and moisture, the KOE is a region of large cyclogenesis, as major storm tracks are organized along or just downstream of the main oceanic frontal zones ( Hoskins and Hodges 2002 ; Bengtsson et al. 2006 ). Nakamura et al. (2004) and Taguchi et al. (2009) have
region, turbulent sensible heat flux (SHF) and latent heat flux (LHF) from the ocean surface are enhanced into a cool dry continental air mass carried by the prevailing monsoonal northerlies (e.g., Kwon et al. 2010 ), especially along the KE because of locally augmented air–sea temperature differences (e.g., Taguchi et al. 2009 ; Tanimoto et al. 2011 ). It has been argued that sharp meridional contrasts in SHF across SST fronts act to restore near-surface baroclinicity efficiently, contributing to
region, turbulent sensible heat flux (SHF) and latent heat flux (LHF) from the ocean surface are enhanced into a cool dry continental air mass carried by the prevailing monsoonal northerlies (e.g., Kwon et al. 2010 ), especially along the KE because of locally augmented air–sea temperature differences (e.g., Taguchi et al. 2009 ; Tanimoto et al. 2011 ). It has been argued that sharp meridional contrasts in SHF across SST fronts act to restore near-surface baroclinicity efficiently, contributing to
