Validation of a mesoscale weather prediction model using subdomain budgets

Abstract

A B S T R A C TThe monitoring of conservation properties is essential for model development and for the investigation of the hydrological cycle. This is especially relevant for models that do not solve equations in flux form and do not apply a finite volume discretization. The conservation properties of the mesoscale model COSMO are evaluated by using a finite volume diagnostic approach. That is the subdomain budget of energy, water mass and total mass are diagnosed in a control volume that can be placed at each site in the model domain and is independent of the grid size. Thus, this diagnostic method has the major advantage that it can be applied to realistic simulations. The application of the diagnostic method to the COSMO model reveals a good preservation of the water mass, but large errors in energy and total mass conservation. The analysis shows to which extent errors in the treatment of thermodynamical processes, numerical filters and moisture advection schemes contaminate the subdomain budgets. In this paper we will show that the application of a saturation adjustment scheme under a fixed volume condition is required for models, which use the non-hydrostatic equations and height-based coordinates. Also, a further extension of the model physics will be introduced and discussed for a realistic test case.

Inter‐comparison of high‐resolution gridded climate data sets and their implication on hydrological model simulation over the Athabasca Watershed, Canada

“…Even though each gridded climate data set incorporates information derived from station‐based climate observations, the reliability of the data vary with the quality and density of observing stations and the topography of the region. Therefore, additional comparisons of each gridded data set with reliable observational data were necessary to identify the most consistent gridded data set corresponding to the different seasons and regions within the ARB (Petrik et al ., ; Lindau and Simmer, ). Observational station data employed in these data sets were obtained from (1) the study of Mekis and Vincent (), who adjusted daily rainfall and snowfall data for 450 stations over Canada that account for not only wind undercatch and evaporation and wetting losses for each type of rain gauges but also a density correction from a set of coincident ruler measurements and Nipher gauge observations for snowfall stations and (ii) the study of Vincent et al .…”

A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores

“…In addition, Wedi and Smolarkiewicz (2009) applied amplified HS forcings within a small-planet testing framework for intercomparisons of nonhydrostatic dynamical cores. Polvani and Kushner (2002) used the HS forcing with a slightly modified equilibrium temperature profile and a high model top to explore the extratropical tropospheric response to imposed stratospheric temperature perturbations. The HS test was also used by Jablonowski (2013, 2015) to analyze a quasi-biennial oscillation (QBO)-like circulation in the tropical stratosphere.…”