Recalculation of error growth models' parameters for the ECMWF forecast system
<p>This article provides a new estimate of error growth models' parameters approximating predictability curves and their differentials, calculated from data of the ECMWF forecast system over the 1986 to 2011 period. Estimates of the largest Lyapunov exponent are also provided, along with...
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| Autores principales: | , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/d53a62f9ff5547ae8c8c14e25e8abea4 |
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| Sumario: | <p>This article provides a new estimate of error growth
models' parameters approximating predictability curves and their
differentials, calculated from data of the ECMWF forecast system over the
1986 to 2011 period. Estimates of the largest Lyapunov exponent are also
provided, along with model error and the limit value of the predictability
curve. The proposed correction is based on the ability of the Lorenz (2005) system to simulate the predictability curve of the ECMWF forecasting
system and on comparing the parameters estimated for both these systems, as
well as on comparison with the largest Lyapunov exponent (<span class="inline-formula"><i>λ</i>=0.35</span> d<span class="inline-formula"><sup>−1</sup></span>) and limit value of the predictability curve (<span class="inline-formula"><i>E</i><sub>∞</sub>=8.2</span>) of the Lorenz system. Parameters are calculated from the quadratic
model with and without model error, as well as by the logarithmic,
general, and hyperbolic tangent models. The average value of the
largest Lyapunov exponent is estimated to be in the <span class="inline-formula"><i><</i></span> 0.32;
0.41 <span class="inline-formula"><i>></i></span> d<span class="inline-formula"><sup>−1</sup></span> range for the ECMWF forecasting system; limit
values of the predictability curves are estimated with lower theoretically
derived values, and a new approach for the calculation of model error based on
comparison of models is presented.</p> |
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