The Weak Temperature Gradient Approximation and Balanced Tropical Moisture Waves

By A. Sobel, Johan Nilsson, L. Polvani. 2001

615 citations recorded by the source corpus.

Subfields: Atmospheric Science, Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/67038d498d9868d9e87a9bc0abb7d8d18110a0eb

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Citations in the corpus

Intraseasonal Variability in an Aquaplanet General Circulation Model (2010, background): “…by the dominant role of latent heat flux and evaporation in the intraseasonal MSE and moisture budgets in the model, as well as other recent evidence in the literature suggesting an important role for WISHE in destabilizing tropical intraseasonal oscillations (e.g. Sobel et al. 2008, 2010).”
An Idealized Semi-Empirical Framework for Modeling the Madden–Julian Oscillation (2012, background): “…modes (sometimes called by other names) have been studied previously in many other models with varying degrees of complexity (Neelin and Yu 1994; Sobel et al. 2001; Fuchs and Raymond 2002, 2005, 2007; Sobel and Bretherton 2003; Raymond and Fuchs 2009; Sugiyama 2009a,b; Majda and Stechmann 2009;…”
Organization of tropical convection in low vertical wind shears: Role of updraft entrainment (2017, background): “The weak temperature gradient (WTG) approximation is assumed to hold, in which gravity waves remove virtual temperature perturbations efficiently [Sobel et al., 2001; Polvani and Sobel , 2002] and convective activity is equal in both columns, with the compensating subsidence balancing radiative…”
Self‐aggregation of convection in long channel geometry (2014, neutral): “If weak temperature gradients can be assumed in the free troposphere (Sobel et al., 2001), then spatial variance in ĥ is dominated by variance in Lv̂q rather than cpT̂.”
Fifty Years of Research on the Madden‐Julian Oscillation: Recent Progress, Challenges, and Perspectives (2020, background): “The first studies indicating that theMJOmay be a moisture mode were Raymond (2001) and Sobel et al. (2001).”
The Dynamics of Idealized Convection Schemes and Their Effect on the Zonally Averaged Tropical Circulation (2007, methodology): “This scheme and simplifications thereof are frequently used in simple or intermediate-complexity models (e.g., Neelin and Yu 1994; Yu and Neelin 1994, 1997; Neelin and Zeng 2000; Sobel et al. 2001; Frierson et al. 2004).”
Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time‐scales (2008, background): “…a suitable balance condition would be indeed very difficult (see alsoẐagar et al., 2005), and it can be shown through asymptotic expansion (Sobel et al., 2001) that the equations then either have wave like solutions or some radiative-convective equilibrium solutions that do not…”
A New Model of the Madden–Julian Oscillation (2001, background): “2) The dynamics of the simulated disturbances can be understood in terms of the quasi-balanced model of Sobel et al. (2001), in which heating interacts with the vorticity equation to produce flows that are predominantly solenoidal in certain critical regions.”
Analytic representation of the large-scale organization of tropical convection (2004, methodology): “These nonlinear models, together with multiscale perturbation models of Majda and Shefter (2001) and balanced models (e.g., Sobel et al. 2001; Majda and Klein 2003) are a framework for basic studies of multiscale convective coherence, including aspects salient to parameterization.”
Moisture modes and the Madden-Julian oscillation. (2009, background): “Raymond (2007) showed that tuning a cumulus parameterization to a CRM in the context of the weak temperature gradient approximation (Sobel and Bretherton 2000; Sobel et al. 2001; Mapes 2004; Raymond and Zeng 2005) results in 4”
A Simple Model of a Convectively Coupled Walker Circulation Using the Weak Temperature Gradient Approximation (2002, background): “A further useful simplification suggested by scale analysis is the weak temperature gradient (WTG) approximation (Sobel and Bretherton 2000; Sobel et al. 2001), in which, to leading order, the tropical troposphere can be assumed to have horizontally uniform temperature, so that adiabatic cooling…”
Evolution of convection during tropical cyclogenesis (2007, methodology): “We rst outline the use of a numerical cloud model in weak temperature gradient (WTG) mode (Sobel and Bretherton 2000; Sobel et al. 2001; Derbyshire et al. 2004; Mapes 2004; Raymond and Zeng 2005) to follow the evolution of convection in the environment characteristic of an intensifying tropical dist”
Systematic Multiscale Models for the Tropics (2003, methodology): “…p ] → (u, w, p), (T , X ) → (t, x), andM M = → =, (3.28)M leads to a system of ‘‘weak temperature gradient’’ equations analogous to those derived, for example, in Browning et al. (2000) and Sobel et al. (2001): ] u 1 u · =u 1 w] u 1 =p 1 byk 3 u 5 S ,t z u = · r u 1 ] (r w) 5 0, and0 z 0 dQ2w 5 S .”
Response of the large‐scale structure of the atmosphere to global warming (2015, background): “Although it is only in convective regions where the moist adiabatic lapse rate directly controls the temperature aloft, horizontal temperature gradients tend to be small at low latitudes (Sobel et al., 2001) and the warming spreads throughout the Tropics.”
Formation of Jets and Equatorial Superrotation on Jupiter (2008, background): “…on a (possibly small) static stability S, giving the weak temperature gradient approximation of the thermodynamic equation2 (Held and Hoskins 1985; Sobel et al. 2001) ωS ≈ −Q. (1) By mass conservation, ∇h · vχ = −∂pω, vertical gradients of diabatic heating and/or static stability thus induce…”