Recent studies of low-frequency variability have shown that at least two planetary-scale statistical flow regimes exist in the Northern Hemisphere winter circulation both in observations and in a general circulation model. This result was obtained from an analysis of a large-scale circulation index based on planetary-wave amplitude. In this paper, a 1200-day integration of the NCAR Community Climate Model (CCM0) in perpetual January mode is used as a case study to show that similar results in terms of multiple flow regimes can also be obtained from an empirical orthogonal function (EOF) analysis. Two modes are found in the probability density distribution in the subspace formed from the leading two EOFs of the model. There is an apparent correspondence between these modes and the two modes deduced from the previous wave-amplitude analysis.
STRUCTURE IN THE PHASE-SPACE OF A GENERAL-CIRCULATION MODEL DEDUCED FROM EMPIRICAL ORTHOGONAL FUNCTIONS / Hansen, Ar; Sutera, Alfonso. - In: JOURNAL OF THE ATMOSPHERIC SCIENCES. - ISSN 0022-4928. - 49:4(1992), pp. 320-326. [10.1175/1520-0469(1992)049<0320:SITPSO>2.0.CO;2]
STRUCTURE IN THE PHASE-SPACE OF A GENERAL-CIRCULATION MODEL DEDUCED FROM EMPIRICAL ORTHOGONAL FUNCTIONS
SUTERA, Alfonso
1992
Abstract
Recent studies of low-frequency variability have shown that at least two planetary-scale statistical flow regimes exist in the Northern Hemisphere winter circulation both in observations and in a general circulation model. This result was obtained from an analysis of a large-scale circulation index based on planetary-wave amplitude. In this paper, a 1200-day integration of the NCAR Community Climate Model (CCM0) in perpetual January mode is used as a case study to show that similar results in terms of multiple flow regimes can also be obtained from an empirical orthogonal function (EOF) analysis. Two modes are found in the probability density distribution in the subspace formed from the leading two EOFs of the model. There is an apparent correspondence between these modes and the two modes deduced from the previous wave-amplitude analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.