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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
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
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
1. Introduction There are many reasons for studying tornado debris clouds. They provide visual signatures of tornadoes, giving clues to their dynamics. Debris loading can contribute significantly to tornado damage. Understanding the differences between the local velocities of debris and air is important for interpreting Doppler radar measurements of tornado wind speeds. Contaminants could be spread long distances if lofted high into the parent storm. Finally, the presence of debris may alter
1. Introduction There are many reasons for studying tornado debris clouds. They provide visual signatures of tornadoes, giving clues to their dynamics. Debris loading can contribute significantly to tornado damage. Understanding the differences between the local velocities of debris and air is important for interpreting Doppler radar measurements of tornado wind speeds. Contaminants could be spread long distances if lofted high into the parent storm. Finally, the presence of debris may alter
1. Introduction Eyewall contraction is closely related to intensification, often rapid intensification, of a tropical cyclone (TC). Therefore, understanding the dynamics of eyewall contraction is of fundamental importance for understanding the dynamics of TC intensification. However, although eyewall contraction is a common feature during the TC intensification, its dynamics has not been well understood so far. Because eyewall contraction is closely tied with the contraction of the radius of
1. Introduction Eyewall contraction is closely related to intensification, often rapid intensification, of a tropical cyclone (TC). Therefore, understanding the dynamics of eyewall contraction is of fundamental importance for understanding the dynamics of TC intensification. However, although eyewall contraction is a common feature during the TC intensification, its dynamics has not been well understood so far. Because eyewall contraction is closely tied with the contraction of the radius of
will have Gaussian PDFs. However, geophysical systems are not necessarily Gaussian, and deviations from Gaussianity can shed light on the underlying dynamics. In recent years, new quantitative tools that make use of advanced stochastic theory have evolved to evaluate extreme events (i.e., infrequent events associated with non-Gaussian statistics) and the physics that govern these events (e.g., Peinke et al. 2004 ; Majda et al. 2008 ; Monahan 2004 , 2006a , b ; Sura 2003 ; Sura and Gille 2003
will have Gaussian PDFs. However, geophysical systems are not necessarily Gaussian, and deviations from Gaussianity can shed light on the underlying dynamics. In recent years, new quantitative tools that make use of advanced stochastic theory have evolved to evaluate extreme events (i.e., infrequent events associated with non-Gaussian statistics) and the physics that govern these events (e.g., Peinke et al. 2004 ; Majda et al. 2008 ; Monahan 2004 , 2006a , b ; Sura 2003 ; Sura and Gille 2003
. Note the logarithmic color scale. The approximate longitude of large topographic features is labeled. The purpose of this study is to explore the dynamics of storm tracks in the Southern Ocean and to develop a physical mechanism that explains their formation near large topographic features and the extension of high EKE farther downstream. a. A review of the dynamics of atmospheric storm tracks The persistence of high EKE in certain geographical regions presented a quandary to meteorologists
. Note the logarithmic color scale. The approximate longitude of large topographic features is labeled. The purpose of this study is to explore the dynamics of storm tracks in the Southern Ocean and to develop a physical mechanism that explains their formation near large topographic features and the extension of high EKE farther downstream. a. A review of the dynamics of atmospheric storm tracks The persistence of high EKE in certain geographical regions presented a quandary to meteorologists
1. Introduction Scale analysis (cf. Charney 1948 ; Burger 1958 ; Phillips 1963 ) is a powerful tool in dynamic meteorology in deriving an approximate governing equation system. The derivation of the quasigeostrophic system for the midlatitude large-scale dynamics by Charney (1948) would probably be the best example. The other examples include the derivation of the anelastic system from a full compressible system ( Ogura and Phillips 1962 ; Lipps and Hemler 1982 ) and of the primitive
1. Introduction Scale analysis (cf. Charney 1948 ; Burger 1958 ; Phillips 1963 ) is a powerful tool in dynamic meteorology in deriving an approximate governing equation system. The derivation of the quasigeostrophic system for the midlatitude large-scale dynamics by Charney (1948) would probably be the best example. The other examples include the derivation of the anelastic system from a full compressible system ( Ogura and Phillips 1962 ; Lipps and Hemler 1982 ) and of the primitive
1. Introduction Tropopause motion plays a crucial part in the dynamics of the atmosphere. Important features of the tropospheric and lower-stratospheric circulation at midlatitude can indeed be well described by considering only balanced motion at the tropopause, near the ground, and their interactions ( Hoskins et al. 1985 ). Furthermore, the role of the tropopause as a barrier to transport makes it crucial for the distribution of atmospheric tracers such as water vapor or ozone. The simplest
1. Introduction Tropopause motion plays a crucial part in the dynamics of the atmosphere. Important features of the tropospheric and lower-stratospheric circulation at midlatitude can indeed be well described by considering only balanced motion at the tropopause, near the ground, and their interactions ( Hoskins et al. 1985 ). Furthermore, the role of the tropopause as a barrier to transport makes it crucial for the distribution of atmospheric tracers such as water vapor or ozone. The simplest
1. Introduction Theoretical and practical motivation for balance dynamics is derived from the search for approximate dynamical systems that accurately reproduce solutions of the full system, but with fewer degrees of freedom. Put differently, the quest in balance dynamics is to accurately compress, or encode, information into fewer variables that I shall refer to as “control” variables. To retrieve the information compressed in these control variables, a decompression algorithm is needed to
1. Introduction Theoretical and practical motivation for balance dynamics is derived from the search for approximate dynamical systems that accurately reproduce solutions of the full system, but with fewer degrees of freedom. Put differently, the quest in balance dynamics is to accurately compress, or encode, information into fewer variables that I shall refer to as “control” variables. To retrieve the information compressed in these control variables, a decompression algorithm is needed to
