Abstract: Equations are derived in coordinate-invariant vector notation for the time rate of change of shear and curvature vorticity. These equations are a generalization of equations in natural coordinates derived 30 years ago by ...

Abstract: A method for analyzing height fields from simultaneous observations of height and wind is proposed which combines Gandin's optimum interpolation concept with the classical approach of extrapolating height values geostrophically ...

Abstract: A numerical model framed in isentropic coordinates is applied to the problem of predicting lee cyclogenesis south of the Alps. Since ?Genoa cyclones? during their initial stage are mesoscale phenomena, while mid-tropospheric ...

Abstract: Using observed data and model simulations, an attempt is made to verify that baroclinic instability can be viewed as an interaction and mutual amplification of a pair of upper- and lower-tropospheric potential vorticity ...

Abstract: In a few selected cases of explosive cyclogenesis, a ?coarse-mesh? nine-level isentropic prediction model conserving potential geostrophic vorticity is shown to yield dependable 36-hr forecasts of developing cyclones. ...

Abstract: The problem of transforming fields of atmospheric variables from one vertical coordinate system to another without altering their dynamic balance is discussed. A curve fitting scheme applied to the data points in each grid ...

Abstract: A comparison is made of several ways to combine isentropic with sigma coordinates in a numerical weather prediction model in order to benefit from the advantage of either coordinate. The resulting hybrid model versions ...

Abstract: Two limited-area prediction models in isentropic coordinates, one based on potential vorticity conservation and one using the primitive equations of motion, are tested on 50 synoptic cases chosen from winter and spring of ...

Abstract: A two-layer isentropic model is used to examine the parameters controlling the severity of cold-air outbreaks east of the Rocky Mountains, and in particular the channeling effect of the mountain range. The case that is ...

Abstract: A numerical experiment is described which explores the relationship between upper-level potential vorticity advection and cyclogenesis on the leeward side of mountain barriers. A multilevel primitive equation model framed ...