Title:Quantification of divergence in a mesoscale model

Authors:Vanja Blazica (University of Ljubljana, Ljubljana, Slovenia)
Nedjeljka Zagar (University of Ljubljana, Ljubljana, Slovenia)

The importance of divergence increases as the scales of atmospheric phenomena decrease. In the mid-latitudes, divergence is an essential ingredient of many mesoscale processes. Its analysis and reliable prediction remains a challenge for mesoscale NWP models. The analysis of divergence in the mesoscale data assimilation systems and associated model errors is a subject of active research. This study aims to quantify the divergent energy on the mesoscale based on the state-of-the-art NWP model ALADIN. The goal is to provide picture of average distribution of divergence versus vorticity as a function of the horizontal scale and the vertical level. Furthermore, it is studied whether the same average percentage of divergence with respect to vorticity, that is present in the model forecast, is characteristic also for the short-range forecast errors.

GMAO Head: Michele Rienecker Global Modeling and Assimilation Office NASA Goddard Space Flight Center

Curator: Nikki Privé Last Updated: May 27 2011