We provide a uni ed description of thermal equilibria of black hole accretion disks, including the newly-discovered advection-dominated solutions. We classify the solutions on the basis of optical depth and importance of advection cooling. We demonstrate that only four physically distinct topological types of equilibria exist. Two of the types correspond to optically thin and optically thick eq...

We study the dynamics of a reaction-diffusion-advection model for two competing species in a spatially heterogeneous environment. The two species are assumed to have the same population dynamics but different dispersal strategies: both species disperse by random diffusion and advection along the environmental gradient, but with different random dispersal and/or advection rates. Given any advect...

We derive local error estimates for the discretization of optimal control problems governed by linear advection-diffusion partial differential equations (PDEs) using the streamline upwind/Petrov Galerkin (SUPG) stabilized finite element method. We show that if the SUPG method is used to solve optimization problems governed by an advection-dominated PDE the convergence properties of the SUPG met...

A partition of the geostrophic vorticity into shear and curvature components is employed to consider the influence of differential vorticity advection on the development of upper level jet-front systems in northwesterly flow in an idealized and an observed case. The analysis reveals that negative geostrophic shear vorticity advection by the thermal wind, inextricably coincident with regions of ...

Output from the regional climate model RACMO2/ANT is used to calculate the heat budget of the Antarctic atmospheric boundary layer (ABL). The main feature of the wintertime Antarctic ABL is a persistent temperature deficit compared to the free atmosphere. The magnitude of this deficit is controlled by the heat budget. During winter, transport of heat towards the surface by turbulence and net lo...

[1] Multi-decadal trends in the advection, mixing, and airsea flux of natural carbon dioxide (CO2) in the Southern Ocean are investigated using output from a hindcast simulation of a non-eddy-resolving ocean model. Particular emphasis is placed on the model’s improved eddy-induced advection parameterization. From 1958 to 2007, the model predicts a significant increase in the outgassing of natur...

Flow distortion over a forested hill is asymmetric, forming a recirculation region on the lee slope that increases the complexity in understanding atmosphere– biosphere interaction. To understand the complexity, we examine the effect of the geometry of forested hills on recirculation formation, structure, and related CO2 transport by performing numerical simulations over doubleforested hills. T...