Nonhydrostatic generalization of a pressure-coordinate-based hydrostatic model with implementation in HIRLAM: validation of adiabatic core

Abstract

A nonhydrostatic pressure‐coordinate model of atmospheric dynamics is developed. The model filters acoustic mode. Internal acoustic waves are filtered using the assumption of non‐divergence of motion in pressure‐space. External (Lamb mode) waves are filtered using the surface pressure adjustment. The model is implemented in the framework of the numerical weather prediction model HIRLAM (High Resolution Limited Area Model) as an extension to the hydrostatic kernel. The integration scheme is either the explicit or semi‐implicit Eulerian leapfrog time stepping. Due to the acoustic filtration, the explicit scheme supports quite large time‐steps. To check the validity of the model, several flow experiments with artificial orography are performed. The hydrostatic and nonhydrostatic flow regimes are investigated. The results of different models are compared mutually and with the analytic solutions. The real situation simulations are also presented to show the model's forecasting capabilities.

Applicability of Large-Scale Convection and Condensation Parameterization to Meso-γ-Scale HIRLAM: A Case Study of a Convective Event

“…The external (Lamb) mode is filtered using a surface pressure adjustment. Männik et al (2003) proved that this anelastic approach was able to produce as good results as its hydrostatic counterpart with an 11-km grid spacing. However, it is still unproven that this nonhydrostatic model performs better than a hydrostatic model in a real case with a smaller grid spacing.…”

“…An anelastic pressure-coordinate-based nonhydrostatic version of HIRLAM has been developed by Rõõm (2001) and Männik and Rõõm (2001). In the anelastic approximation, all internal acoustic wave modes are filtered and large time steps are allowed, even with an explicit time scheme.…”

Multidisciplinary numerical model of a coastal water ecosystem

“…The mesh size of the large domain (denoted ETA) equals 11 km and the mesh size of the smaller domain (denoted ETB) equals 3 km [10]. The mesh size of the large domain (denoted ETA) equals 11 km and the mesh size of the smaller domain (denoted ETB) equals 3 km [10].…”

“…These are the weather prediction model HIRLAM, the mesoscale atmosphere models ETA and ETB [10], the wind-wave model in the narrow-directional approximation [16,19], the model of mesoscale sea/lake circulation combined with the turbulence k-ω model [12], and the sea ecosystem model [6,14]. These are the weather prediction model HIRLAM, the mesoscale atmosphere models ETA and ETB [10], the wind-wave model in the narrow-directional approximation [16,19], the model of mesoscale sea/lake circulation combined with the turbulence k-ω model [12], and the sea ecosystem model [6,14].…”

Non-hydrostatic semi-elastic hybrid-coordinate SISL extension of HIRLAM. Part I: numerical scheme

“…That has been the main motivation for the introduction of the MPW model rather than of the 'full' pressure-coordinate dynamics (Rõõm, 1990). The MPW model has been already applied with success in heretofore developed three-time-level, explicit-Eulerian (Männik and Rõõm, 2001), and SI Eulerian (Rõõm and Männik, 2002;Männik et al, 2003) schemes of HIRLAM. The aim of the present paper is to present the SISL extension of these implementations.…”