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, and El Niño episodes, plus the curved coastline and the large submarine canyon, all need to be taken into account for a faithful reconstruction of the processes as observed ( Rosenfeld et al. 1994 ). The problem is therefore rather generic; in other words, it would be very difficult to rely on simplification of certain factors to gain a convincing understanding of the dynamics. Clearly, the complex configuration and the highly variable environment pose a great challenge to our study. During the
, and El Niño episodes, plus the curved coastline and the large submarine canyon, all need to be taken into account for a faithful reconstruction of the processes as observed ( Rosenfeld et al. 1994 ). The problem is therefore rather generic; in other words, it would be very difficult to rely on simplification of certain factors to gain a convincing understanding of the dynamics. Clearly, the complex configuration and the highly variable environment pose a great challenge to our study. During the
2017. Apart from a full attribution, this paper focuses on the general dynamics that could link the Arctic warming with Eurasian cooling. Regarding dynamics, there are extensive works published. Here, a detailed review of all the previous works is not necessary because some excellent reviews are already available, such as those of Cohen et al. (2014 , 2018 ), Overland et al. (2016) , Coumou et al. (2018) , and Screen et al. (2018) . Previous works suggest many possible pathways linking the
2017. Apart from a full attribution, this paper focuses on the general dynamics that could link the Arctic warming with Eurasian cooling. Regarding dynamics, there are extensive works published. Here, a detailed review of all the previous works is not necessary because some excellent reviews are already available, such as those of Cohen et al. (2014 , 2018 ), Overland et al. (2016) , Coumou et al. (2018) , and Screen et al. (2018) . Previous works suggest many possible pathways linking the
the AMO is a direct response of the ocean to atmospherically generated NAO variations and associated turbulent surface heat flux variations, combined with wind–evaporation–SST feedback in the tropics. However, this new perspective is challenged by recent analyses showing that ocean dynamics plays a central role in the AMO ( Zhang et al. 2016 ; O’Reilly et al. 2016 ). In this study, we reexamine the connection between the NAO and Atlantic SST variability across a range of time scales using a
the AMO is a direct response of the ocean to atmospherically generated NAO variations and associated turbulent surface heat flux variations, combined with wind–evaporation–SST feedback in the tropics. However, this new perspective is challenged by recent analyses showing that ocean dynamics plays a central role in the AMO ( Zhang et al. 2016 ; O’Reilly et al. 2016 ). In this study, we reexamine the connection between the NAO and Atlantic SST variability across a range of time scales using a
circulation. A simple estimate (R. W. Schmitt 2012, personal communication) suggests that the salt flux over a relatively small area of the Caribbean staircase exceeds the net turbulent transport due to overturning gravity waves throughout the entire North Atlantic subtropical thermocline. Despite the persistent interest in thermohaline staircases, their dynamics are still surrounded by controversy. While the origin of staircases is undoubtedly double diffusive, specific mechanisms of layering are poorly
circulation. A simple estimate (R. W. Schmitt 2012, personal communication) suggests that the salt flux over a relatively small area of the Caribbean staircase exceeds the net turbulent transport due to overturning gravity waves throughout the entire North Atlantic subtropical thermocline. Despite the persistent interest in thermohaline staircases, their dynamics are still surrounded by controversy. While the origin of staircases is undoubtedly double diffusive, specific mechanisms of layering are poorly
al. (2010) found consistency of the vertical propagation of the equatorial Rossby waves in an ocean general circulation model (OGCM) with the linear theory. Kessler and McPhaden (1995) pointed out the importance of multiple baroclinic modes of the Kelvin waves and the first meridional mode equatorial Rossby waves in the intraseasonal-to-interannual variability of the equatorial Pacific Ocean circulation. The dynamics of the off-equatorial subsurface zonal currents, which are influenced by both
al. (2010) found consistency of the vertical propagation of the equatorial Rossby waves in an ocean general circulation model (OGCM) with the linear theory. Kessler and McPhaden (1995) pointed out the importance of multiple baroclinic modes of the Kelvin waves and the first meridional mode equatorial Rossby waves in the intraseasonal-to-interannual variability of the equatorial Pacific Ocean circulation. The dynamics of the off-equatorial subsurface zonal currents, which are influenced by both
of climate models ( Guilyardi et al. 2009 ; Guilyardi et al. 2012 ; Bellenger et al. 2014 ; Capotondi et al. 2015 ; Chen et al. 2017 ; Capotondi et al. 2020a , b ; Guilyardi et al. 2020 ). In fact, a detailed analysis of coupled dynamics revealed significant biases in simulating ENSO feedback processes. For instance, Guilyardi et al. (2009) and Lloyd et al. (2009) noted that the dynamic feedback efficiency or the atmospheric Bjerknes positive feedback parameter—a measure of the strength
of climate models ( Guilyardi et al. 2009 ; Guilyardi et al. 2012 ; Bellenger et al. 2014 ; Capotondi et al. 2015 ; Chen et al. 2017 ; Capotondi et al. 2020a , b ; Guilyardi et al. 2020 ). In fact, a detailed analysis of coupled dynamics revealed significant biases in simulating ENSO feedback processes. For instance, Guilyardi et al. (2009) and Lloyd et al. (2009) noted that the dynamic feedback efficiency or the atmospheric Bjerknes positive feedback parameter—a measure of the strength
1. Introduction The near-tropopause horizontal wavenumber energy spectrum has a remarkably simple, double-power-law shape, with a steep −3 slope at synoptic scales breaking to a shallower −5/3 slope at mesoscales ( Nastrom and Gage 1985 ). Synoptic-scale dynamics are typically interpreted in the light of Charney (1971) ’s theory of geostrophic turbulence, which predicts a forward enstrophy cascade along a −3 spectrum below the baroclinic injection scale. By contrast, there is yet to be a
1. Introduction The near-tropopause horizontal wavenumber energy spectrum has a remarkably simple, double-power-law shape, with a steep −3 slope at synoptic scales breaking to a shallower −5/3 slope at mesoscales ( Nastrom and Gage 1985 ). Synoptic-scale dynamics are typically interpreted in the light of Charney (1971) ’s theory of geostrophic turbulence, which predicts a forward enstrophy cascade along a −3 spectrum below the baroclinic injection scale. By contrast, there is yet to be a
the intensity of the tropical rainbelt and to shifts in its latitudinal location are examined. A linear model is used to simulate wave growth by following the release of a perturbation in a zonal flow constructed using data that describe the dynamics in the West African region. Detailed basic-state plots of zonal wind, potential temperature, and stratification of the summer months of different years provide a rich backdrop in which to understand the perturbations’ growth. The basic states of two
the intensity of the tropical rainbelt and to shifts in its latitudinal location are examined. A linear model is used to simulate wave growth by following the release of a perturbation in a zonal flow constructed using data that describe the dynamics in the West African region. Detailed basic-state plots of zonal wind, potential temperature, and stratification of the summer months of different years provide a rich backdrop in which to understand the perturbations’ growth. The basic states of two
mixing, while in the diathermal framework the role of temperature advection in the heat budget is not considered ( Walin 1982 ; Holmes et al. 2019 ). For our purposes of separating the role of ocean physics and dynamics at different scales, the applied projection of the Eulerian heat budget onto the position of potential density surfaces is as follows. Consider the whole ocean domain, so that Eq. (5) takes the form (9) All scales = Large + Meso + Small + Flux δ ( z − η ) , where we assume
mixing, while in the diathermal framework the role of temperature advection in the heat budget is not considered ( Walin 1982 ; Holmes et al. 2019 ). For our purposes of separating the role of ocean physics and dynamics at different scales, the applied projection of the Eulerian heat budget onto the position of potential density surfaces is as follows. Consider the whole ocean domain, so that Eq. (5) takes the form (9) All scales = Large + Meso + Small + Flux δ ( z − η ) , where we assume
transverse circulation by the geostrophic flow component in the upper-level jet streak ( Shapiro 1981 ; Shapiro et al. 1984 ). However, ULFs seem to be a part of the synoptic-scale baroclinic waves in general ( Reed 1955 ; Newton 1958 ; Nieman et al. 1998 ). A 2D semigeostrophic model was used by Hoskins (1972) to demonstrate the formation of ULFs driven by an imposed vertically uniform confluent flow. The dynamics of frontogenesis was interpreted as a feedback process in the context of a developing
transverse circulation by the geostrophic flow component in the upper-level jet streak ( Shapiro 1981 ; Shapiro et al. 1984 ). However, ULFs seem to be a part of the synoptic-scale baroclinic waves in general ( Reed 1955 ; Newton 1958 ; Nieman et al. 1998 ). A 2D semigeostrophic model was used by Hoskins (1972) to demonstrate the formation of ULFs driven by an imposed vertically uniform confluent flow. The dynamics of frontogenesis was interpreted as a feedback process in the context of a developing
