Abstract. This paper presents a characteristic-based flux partitioning for the semi-implicit time integration of atmospheric flows. Nonhydrostatic models require the solution of the compressible Euler equations. The acoustic time-scale is significantly faster than the advective scale, yet it is typically not relevant to atmospheric and weather phenomena. The acoustic and advective components of...

Lab-scale tests were set up to investigate different options for achieving sustainability by reducing long-term landfill emissions. The options which have been studied and compared with the traditional anaerobic landfill for unprocessed refuse were: mechanical-biological pretreatment, landfill aeration with forced and with natural advective air flow (semi-aerobic), flushing. Combination of diff...

Version: September 12, 2000 Abstract. We consider in this paper a semi{Lagrangian technique to treat advection{di usion equations. The scheme is based on a stochastic representation formula for the solution which allows to avoid the splitting between advective and di usive part of the evolution operator. This results in a somewhat reduced computational complexity, as well as the possibility to ...

The conditions for disk evaporation by electron thermal conduction are examined, using a simplified semi–analytical 1-D model. The model is based on the mechanism proposed by Meyer & Meyer–Hofmeister (1994) in which an advection dominated accretion flow evaporates the top layers from the underlying disk by thermal conduction. The evaporation rate is calculated as a function of the density of th...

We study a two-species competition model in a closed advective environment, where individuals are exposed to unidirectional flow (advection) but no individuals are lost through the boundary. The two species have the same growth and advection rates but different random dispersal rates. The linear stability analysis of the semi-trivial steady state suggests that, in contrast to the case without a...

We discuss alternative methods for prescribing advective tendencies in singlecolumn models (SCMs) and cloud system models. These include “revealed forcing,” in which the total advective tendency is prescribed from observations; “horizontal advective forcing,” in which the horizontal advective tendencies are prescribed, together with the observed vertical motion which is combined with the predic...