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‘Superparameterization’ and statistical emulation in the Lorenz '96 system
Author(s) -
Wilks D. S.
Publication year - 2012
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.1866
Subject(s) - emulation , autocorrelation , forcing (mathematics) , computer science , representation (politics) , scale (ratio) , statistical analysis , statistical physics , statistics , mathematics , physics , mathematical analysis , quantum mechanics , politics , political science , law , economics , economic growth
Abstract An idealized ‘superparameterization’, or abbreviated but dynamically explicit representation of small‐scale influences on the conventionally resolved larger scales of a dynamical model, is constructed within the Lorenz '96 system. The feasibility of abstracting the greater portion of its information content using computationally much faster statistical summaries, or emulators, is investigated through integration of a large number of ensemble forecasts. Even though based on an extremely small training‐sample size, consistent with an assumed high computational expense for running a full superparameterization, some of the statistical emulator formulations perform nearly as well as the superparameterization forecast ensembles. As in previous studies, better forecast characteristics are generally achieved when autocorrelated random forcing is included, both in the otherwise deterministic superparameterization and in its statistical emulators. Copyright © 2012 Royal Meteorological Society