Grundlagen einer Theorie der tropischen Zyklonen

Kleinschmidt, Erich

doi:10.1007/bf02246793

Cited by 107 publications

(55 citation statements)

References 7 publications

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“…As proposed by Kleinschmidt (1951) and Riehl (1954), latent and sensible heat fluxes from the sea surface are crucial to TC genesis and intensification. Decades of numerical simulations have verified the fundamental role of surface fluxes (Ooyama, 1969;Rotunno and Emanuel, 1987; Nguyen et al, 2008).…”

Section: Theorymentioning

confidence: 92%

Thermodynamic control of tropical cyclogenesis in environments of radiative‐convective equilibrium with shear

Rappin

Nolan

Emanuel

2010

Quart J Royal Meteoro Soc

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The potential for tropical cyclone formation from a pre-existing disturbance is further explored with high-resolution simulations of cyclogenesis in idealized, tropical environments. These idealized environments are generated from simulations of radiative-convective equilibrium with fixed sea-surface temperatures (SSTs), imposed mean surface winds, and an imposed profile of vertical wind shear. The propensity for tropical cyclogenesis in these environments is measured in two ways: first, in the period of time required for a weak, mid-level circulation to transition to a developing tropical cyclone; and second, from the value of an incubation parameter that incorporates environmental measures of mid-level saturation deficit and thermodynamic disequilibrium between the atmosphere and ocean. Conditions of tropospheric warming can be produced from increased SSTs or from increased mean surface winds; in either case, the time to genesis increases with atmospheric warming. As these parameters are varied, the incubation parameter is found to be highly correlated with changes in the time to genesis.The high resolution (3 km) of these simulations permits analysis of changes in tropical cyclogenesis under warming conditions at the vortex scale. For increasing SST, increased mid-level saturation deficits (dryness) are the primary reason for slowing or preventing genesis. For environments with increased surface wind, it is the decreased thermodynamic disequilibrium between the atmosphere and ocean that delays or prevents development. An additional effect in both cases is a decoupling of the low-level and mid-level vortices, primarily as a result of increased advecting flow at the altitude of the mid-level vortex, which is linked to the height of the freezing level.

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Section: Theorymentioning

confidence: 92%

Thermodynamic control of tropical cyclogenesis in environments of radiative‐convective equilibrium with shear

Rappin

Nolan

Emanuel

2010

Quart J Royal Meteoro Soc

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“…Although the evaporation of water from the underlying ocean has been long recognised as the ultimate energy source for tropical cyclones (Kleinschmidt 1951;Riehl 1954;Malkus and Riehl 1960;Ooyama 1969), 15 Emanuel's contributions with colleagues re-focused attention on the airsea interaction aspects of the intensification process. Rather than viewing latent heat release in deep convective towers as the 'driving mechanism' for vortex amplification, this body of work showed that certain aspects of these storms could be understood in terms of a simple time-dependent model in which the latent heat release was implicit.…”

Section: A Steady-state Hurricane Modelmentioning

confidence: 99%

Paradigms for tropical cyclone intensification

Montgomery¹,

Smith²

2014

AMOJ

192

137

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We review the four main paradigms of tropical cyclone intensification that have emerged over the past five decades, discussing the relationship between them and highlighting their strengths and weaknesses. A major focus is on a new paradigm articulated in a series of recent papers using observations and highresolution, three-dimensional, numerical model simulations. Unlike the three previous paradigms, all of which assumed axial symmetry, the new one recognises the presence of localised, buoyant, rotating deep convection that grows in the rotation-rich environment of the incipient storm, thereby greatly amplifying the local vorticity. It exhibits also a degree of randomness that has implications for the predictability of local asymmetric features of the developing vortex. While surface moisture fluxes are required for intensification, the postulated 'evaporation-wind' feedback process that forms the basis of an earlier paradigm is not. Differences between spin up in three-dimensional and axisymmetric numerical models are discussed also.In all paradigms, the tangential winds above the boundary layer are amplified by the convectively-induced inflow in the lower troposphere in conjunction with the approximate material conservation of absolute angular momentum. This process acts also to broaden the outer circulation. Azimuthally-averaged fields from high-resolution model simulations have highlighted a second mechanism for amplifying the mean tangential winds. This mechanism, which is coupled to the first via boundary-layer dynamics, involves the convergence of absolute angular momentum within the boundary layer, where this quantity is not materially conserved, but where air parcels are displaced much further radially inwards than air parcels above the boundary layer. It explains why the maximum tangential winds occur in the boundary layer and accounts for the generation of supergradient wind speeds there. The boundary layer spin-up mechanism is not unique to tropical cyclones. It appears to be a feature of other rapidly-rotating atmospheric vortices such as tornadoes, waterspouts and dust devils and is manifest as a type of axisymmetric vortex breakdown. The mechanism for spin up above the boundary layer can be captured approximately by balance dynamics, while the boundary layer spin-up mechanism cannot. The spin-up process, as well as the structure of the mature vortex, are sensitive to the boundary-layer parameterisation used in the model.

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“…To the best of this author's knowledge, this is the first paper in which it is explicitly recognized that the energy source of hurricanes arises from the in situ evaporation of ocean water 1 . By the next year, another German scientist, Ernst Kleinschmidt, could take it for granted that "the heat removed from the sea by the storm is the basic energy source of the typhoon" (Kleinschmidt, 1951). Kleinschmidt also showed that thermal wind balance in a hurricane-like vortex, coupled with assumed moist adiabatic lapse rates on angular momentum surfaces, implies a particular shape of such surfaces.…”

Section: Energeticsmentioning

confidence: 99%

“…The expression (16) was derived on quite different grounds by Kleinschmidt (1951) and later by Emanuel (1986). They assumed hydrostatic and gradient wind balance from the start, and simply integrated the thermal wind equation upward along angular momentum surfaces assuming that the saturation entropy, * s , is constant on angular momentum surfaces.…”

Section: Energeticsmentioning

confidence: 99%