Meteorology and Atmospheric Physics

, Volume 50, Issue 1, pp 47–60

On the impact on forecast accuracy of the step-mountain (eta) vs. sigma coordinate

  • Fedor Mesinger
  • Thomas L. Black

DOI: 10.1007/BF01025504

Cite this article as:
Mesinger, F. & Black, T.L. Meteorl. Atmos. Phys. (1992) 50: 47. doi:10.1007/BF01025504


Impact on forecast accuracy of the choice of the step-mountain (“eta”) vs. the traditional sigma coordinate is examined by using a model which can be run as either an eta or sigma system model via a simple switch in its code. This is done by (a) synoptic examination of the differences in a set of three forecasts, and (b) comparison of precipitation skill scores in a set of nine consecutive forecasts; each of these sets of forecasts was performed using one and then the other of the two systems. Both efforts indicate that greater accuracy is achnieved in the step-mountain coordinate forecasts. The three forecasts examined from the synoptic point of view are also compared against forecasts of another sigma system model. The two sigma models are found to have errors of an almost identical pattern (two cases) or to have errors which seemed to have the same basic cause.

Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Fedor Mesinger
    • 1
  • Thomas L. Black
    • 2
  1. 1.UCAR Visiting Research Program at the U.S. National Meteorological CenterUSA
  2. 2.National Meteorological CenterNSW, NOAAWashington, D.C.USA

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