On the impact on forecast accuracy of the step-mountain (eta) vs. sigma coordinate
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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.
- Achtemeier, G. L., 1991: Reducing hydrostatic truncation error in a mesobeta boundary layer model.Mon. Wea. Rev.,119, 223–229.
- Anthes, R. A., 1983: Regional models of the atmosphere in middle latitudes.Mon. Wea. Rev.,111, 1306–1335.
- Arakawa, A., 1988: Finite-difference methods in climate modeling. In: Schlesinger, M. E. (ed.)Physically-Based Modelling and Simulation of Climate and Climatic Change, Part I. Dordrecht: Kluwer Academic, 79–168.
- Carroll, J. J., Mendez-Nunez, L. R., Tanrikulu, S., 1987: Accurate pressure gradient calculations in hydrostatic atmospheric models.Bound-Layer Meteor. 41, 149–169.
- Gandin, L. S., Murphy, A. H., 1992: Equitable skill scores for categorical forecasts.Mon. Wea. Rev.,120, 361–370.
- Haney, R. L., 1991: On the pressure gradient force over steep topography in sigma coordinate ocean models.J Phys. Oceanogr.,21, 610–619.
- Hoke, J. E., Phillips, N. A., DiMego, G. J., Tuccillo, J. J., Sela, J. G., 1989: The regional analysis and forecast system of the National Meteorological Center.Wea. Forecasting,4, 323–334.
- Janjić, Z. I., 1977: Pressure gradient force and advection scheme used for forecasting with steep and small scale topography.Contrib. Atmos. Phys.,50, 186–199.
- Janjić, Z. I., 1990: The step-mountain coordinate: physical package.Mon. Wea. Rev.,118, 1429–1443.
- Mesinger, F., 1982: On the convergence and error problems of the calculation of the pressure gradient force in sigma coordinate models.Geophys. Astrophys. Fluid. Dyn.,19, 105–117.
- Mesinger, F., 1984: A blocking technique for representation of mountains in atmospheric models.Riv. Meteor. Aeronautica,44, 195–202
- Mesinger, F., 1988: False precipitation enhancement due to the vertical moisture advection scheme. Res. Activities Atoms. Oceanic Modelling, Rept. No. 11, WMO, Geneva, 3.22–3.23.
- Mesinger, F., 1990: “Horizontal” pressure reduction to sea level. Preprints, 21. Internationale Tagung für Alpine Meteorologie, 17.–21. September 1990, Engelberg, Schweiz. Schweizerische meteorologische Anstalt, Krähbühlstrasse 58, CH-8044 Zürich, Switzerland, 31–35.
- Mesinger, F., Black T. L., Janjić, Z. I., 1988a: Sigma system contribution to systematic errors in models of the atmosphere. Workshop on Systematic Erros in Models of the Atmosphere, Toronto, 19–23 September 1988, CAS/JSC Working Group of Numerical Experimentation Rept. No.12, WMO, Geneva, 253–263.
- Mesinger, F., Janjić, Z. I., 1987: Numerical techniques for the representation of mountains in atmospheric models. Observation, Theory and Modelling of Orographic Effects, Seminar/workshop 1986, Vol. 2, ECMWF, Shinfield Park, Reading, U. K., 29–80.
- Mesinger, F., Janjić, Z. I., 1990: Numerical methods for the primitive equations (space). 10 Years of Medium-Range Weather Forecasting, Seminar 1989, Vol. 1, ECMWF, Shinfield Park, Reading, U.K., 205–251.
- Mesinger, F., Janjić, Z. I., Ničković, S. Gavrilov, D., Deaven, D. G., 1988b: The step-mountain coordinate: model description and performance for cases of Alpine lee cyclogenesis and for a case of Applachian redevelopment.Mon. Wea. Rev.,116, 1493–1518.
- Mesinger, F., Lobocki, L., 1991: Sensitivity to the parameterization of surface fluxes in NMC's eta model. Preprints, Ninth Conf. Numerical Weather Prediction, Denver, CO, Amer. Meteor. Soc., 213–216. [Boston, MA 02108.]
- Schaefer, J. T., 1990: The critical success index as an indicator of warning skill.Wea. Forecasting,5, 570–575.
- Simmons, A. J., Burridge, D. M., 1981: An energy and angularmomentum conserving vertical finite-difference scheme and hybrid vertical coordinates.Mon. Wea. Rev.,109, 758–766.
- Thompson, W. T., Burk, S. D., 1991: An investigation of an arctic front with a vertically nested mesoscale model.Mon. Wea. Rev.,119, 233–261.
- On the impact on forecast accuracy of the step-mountain (eta) vs. sigma coordinate
Meteorology and Atmospheric Physics
Volume 50, Issue 1-3 , pp 47-60
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