Articles | Volume 8, issue 6
Development and technical paper
23 Jun 2015
Development and technical paper |  | 23 Jun 2015

Reaching the lower stratosphere: validating an extended vertical grid for COSMO

J. Eckstein, S. Schmitz, and R. Ruhnke

Abstract. This study presents an extended vertical grid for the regional atmospheric model COSMO (COnsortium for Small-scale MOdeling) reaching up to 33 km. The extended setup has been used to stably simulate 11 months in a domain covering central and northern Europe. Temperature and relative humidity have been validated using radiosonde data in polar and temperate latitudes, focussing on the polar and mid-latitude stratosphere over Europe. Temperature values are reproduced very well by the model. Relative humidity could only be met in the mean over the whole time period after excluding data from Russian stations, which showed significantly higher values. A sensitivity study shows the stability of the model against different forcing intervals and damping layer heights.

Short summary
An extended vertical grid, which reaches the lower stratosphere, for the regional atmospheric model COSMO was developed. This extended vertical grid was used in model runs simulating almost a full year. The model output was then validated using temperature and relative humidity measurements taken from synoptic radiosondes. Using this extended vertical grid, the model was found to run stably and produce realistic values.