A generalization of Lorenz's model for the predictability of flows with many scales of motion

AMS Citation:
Rotunno, R., and C. Snyder, 2008: A generalization of Lorenz's model for the predictability of flows with many scales of motion. Journal of the Atmospheric Sciences, 65, 1063-1076, doi:10.1175/2007JAS2449.1.
Date:2008-03-01
Resource Type:article
Title:A generalization of Lorenz's model for the predictability of flows with many scales of motion
Abstract: In a seminal paper, E. N. Lorenz proposed that flows with many scales of motion in which smaller-scale error spreads to larger scales and in which the error-doubling time decreases with decreasing scale have a finite range of predictability. Although the Lorenz theory of limited predictability is widely understood and accepted, the model upon which the theory is based is less so. The primary objection to the model is that it is based on the two-dimensional vorticity equation (2DV) while simultaneously emphasizing results using a basic turbulent flow with a "-5/3" energy spectrum in the atmospheric synoptic scale instead of those using a more theoretically and observationally consistent "-3" spectrum. The present work generalizes the Lorenz model so that it may apply to the surface quasigeostrophic equations (SQGs), which are mathematically very similar to 2DV but are known to have a -5/3 kinetic energy spectrum downscale from a large-scale forcing. This generalized Lorenz model is applied here to both 2DV (with a -3 spectrum) and SQG (with a -5/3 spectrum), producing examples of flows with unlimited and limited predictability, respectively. Comparative analysis of the two models allows for the identification of the distinctive attributes of a many-scaled flow with limited predictability.
Subject(s):Kinetic energy, Vorticity, Error analysis, Quasigeostrophic models
Peer Review:Refereed
Copyright Information:Copyright 2008 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be "fair use" under Section 107 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Law (17 USC, as revised by P.L. 94-553) does not require the Society's permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statements, requires written permission or license from the AMS. Additional details are provided in the AMS Copyright Policies, available from the AMS at 617-227-2425 or amspubs@ametsoc.org. Permission to place a copy of this work on this server has been provided by the AMS. The AMS does not guarantee that the copy provided here is an accurate copy of the published work.
OpenSky citable URL: ark:/85065/d7cj8dnk
Publisher's Version: 10.1175/2007JAS2449.1
Author(s):
  • Richard Rotunno - NCAR/UCAR
  • Chris Snyder - NCAR/UCAR
  • Random Profile

    SOFT ENG/PROG III

    Recent & Upcoming Visitors