Repository: Freie Universität Berlin, Math Department

Large-scale secondary circulations in a limited area model - the impact of lateral boundaries and resolution

Becker, N. and Névir, P. and Klein, R. (2018) Large-scale secondary circulations in a limited area model - the impact of lateral boundaries and resolution. Tellus A: Dynamic Meteorology and Oceanography, 70 (1).

Full text not available from this repository.


Within their domain, regional climate and weather forecasting models deviate from the driving data. Small-scale deviations are a desired effect of adding regional details. There are, however, also deviations of the large-scale circulation, which can be caused by orographic effects and depend on the large-scale flow condition. These ‘secondary circulations’ (SCs) are confined to the model domain due to the prescribed boundary conditions. Here, the impact of different regional model configurations on the SC is analysed in a case study for the European region using an ensemble approach. It is shown that at 500 hPa, vortices of the SC have diameters on the order of several thousand kilometres and are related to wind speed anomalies of more than 5 m/s and geopotential height anomalies of more than 5 dam. The spatial structure and the amplitude of the SC strongly depend on the location of the lateral boundaries. The impact of the boundary location on the anomalies is on the same order of magnitude as the anomalies themselves. The resolution of the regional model, as well as the application of spectral nudging and a smoothed topography, affects mainly the amplitude of the SC, but not the spatial structure.

Item Type:Article
Uncontrolled Keywords:Limited area model, regional climate model, COSMO-CLM, secondary circulation, boundary effects, orographic effects
Subjects:Mathematical and Computer Sciences > Mathematics > Applied Mathematics
Divisions:Department of Mathematics and Computer Science > Institute of Mathematics > Geophysical Fluid Dynamics Group
ID Code:2315
Deposited By: Ulrike Eickers
Deposited On:18 Mar 2019 12:45
Last Modified:18 Mar 2019 12:45

Repository Staff Only: item control page