A 30-day oscillation over the North Atlantic - Observation and simulation

Juhani Rinne; Simo Järvenoja

doi:10.3402/tellusa.v47i5.11548

A 30-day oscillation over the North Atlantic - Observation and simulation

Tellus

Volume 47 (1995): Issue 5

By: Juhani Rinne and Simo Järvenoja

Open Access

|Jan 1995

Abstract

A spectral peak at a period of 30 days found in a certain EOF series is studied. A westward-moving wave local to the North Atlantic has been found. The wave is often present and is rather intense. In half of the cases, it is associated with a blocking. The wave can then be described as a retrograde blocking in the Scandinavian-Atlantic sector. It is shown that the oscillation can be viewed as a mode of the non-linear barotropic atmosphere. Three fields are needed in order to simulate the oscillation, i.e., the mean field, an initial anomaly field and a forcing field. All three fields are determined with the aid of the adjoint method by requiring that the oscillation patterns simulated and observed must be as alike as possible. The three fields mentioned have been the unknowns of the problem and the oscillation observed has been the only known variable.

References

Akaike , H. 1969 . Power spectrum estimation through autoregressive model fitting. Ann.Inst. Stat. Math . 21 , 407 – 419.
Search in Google Scholar Back to article
Branstator , G . 1987 . A striking example of the atmospheric leading traveling pattern. J. Atmos. Sc i . 44 , 2310 – 2323 .
Search in Google Scholar Back to article
Ghil , M. and Mo , K . 1991 . Interseasonal oscillation in the global atmosphere. Part I: Northernhemisphere and tropics. J. Atmos. Sc i . 49 , 752 – 779 .
Search in Google Scholar Back to article
Gutzler , D. and Madden , R . 1993 . Seasonal variations of the 40-50-day oscillation in atmospheric angular momentum. J. Atmos. Sc i . 50 , 850 – 860 .
Search in Google Scholar Back to article
Järvinen , H . 1993 . A direct conversion of model algorithms to their adjoints exemplified with a barotropic atmospheric model. Report no. 42, Department of Meteorology, University of Helsinki, Finland , 41 pp. Kidson , J. 1985 . Index cycles in the northern hemisphere during the global weather experiment. Mon. Wea. Re v . 113 , 607 – 623 .
Search in Google Scholar Back to article
Krishnamurti , T. and Gadgil , S . 1985 . On the structure of the 30 to 50 day mode over the globeduring FGGE . Tellus 37A , 336 – 360 .
Search in Google Scholar Back to article
Kushnir , Y. and Esbensen , S. K . 1986 . Diagnosis of low-frequency , extratropical disturbances in a two-level general circulation model. Long-Range Forecasting Research ReportsSeries No. 6 (WMO/TD No. 87) , 521 – 529 .
Search in Google Scholar Back to article
Lamb , H . 1972 . Climate: present, past and future, vol . 1. Methuen & Go Ltd ., London , 613 pp .
Search in Google Scholar Back to article
Lejenäs , H. and Madden , R . 1992 . Traveling planetary—scale waves and blocking. Mon. Wea. Re v . 120 , 2821 – 2830 .
Search in Google Scholar Back to article
Madden , R. and Julian , P . 1971 . Detection of a 40-50 day oscillation in the zonal wind in the tropical Pacific. J. Atmos. Sc i . 28 , 702 – 708 .
Search in Google Scholar Back to article
Madden , R. and Julian , P . 1972 . Description of global scale circulation cells in the tropics with a 40-50 day period. J. Atmos. Sc i . 29 , 1109 – 1123 .
Search in Google Scholar Back to article
Namias , J . 1943 . Methods of extended forecasting . US Weather Bureau , Washington DC , 64 pp .
Search in Google Scholar Back to article
Namias , J . 1947 . Extended forecasting by mean circulation methods . US Weather Bureau , Washington DC , 55 pp .
Search in Google Scholar Back to article
Namias , J . 1950 . The index cycle and its role in the general circulation . J. Meteor . 7 , 130 – 139 .
Search in Google Scholar Back to article
Rinne , J. and Järvenoja , S . 1979 . Truncation of the EOF series representing 500 mb heights . Quart. J. Roy. Meteor. Soc . 105 , 885 – 897 .
Search in Google Scholar Back to article
Rinne , J. and Järvinen , H . 1993 . Estimation of the Cressman term for a barotropic model through optimization with use of the adjoint model. Mon. Wea. Re v . 121 , 825 – 833 .
Search in Google Scholar Back to article
Rinne , J. and Karhila , V . 1979 . Empirical orthogonal functions of 500 mb height in the Northern Hemisphere determined from a large data sample . Quart. J. Roy. Meteor. Soc . 105 , 873 – 884 .
Search in Google Scholar Back to article
Rinne , J. , Karhila , V. and Järvenoja , S . 1981 . The E0Fs of the 500 mb height in the extratropics of the Northern Hemisphere . Report No. 17, Department of Meteorology, University of Helsinki, 00100 Helsinki 10, Finland, 16 pp. + Appendix, suppl. , 88 pp.
Search in Google Scholar Back to article
Rinne , J. and Sarkanen , A . 1985 . 500 mb geopotential height spectral peaks in the 1- to 5-weekrange . Tellus 374 , 323 – 335 .
Search in Google Scholar Back to article
Sawyer , J. S . 1970 . Observational characteristics of atmospheric fluctuations with a time scale of a month . Quart. J. Roy. Meteor. Soc . 96 , 610 – 625 .
Search in Google Scholar Back to article
Sheng , J . 1994 . Assessment of the Interactions between slow transients and synoptic-scale eddies in a T32 general circulation model. #2.43 in: Research activities in atmospheric and oceanic modelling (ed. G. J. Boer ). Report no. 19 by CAS/JSC Working Group on Numerical Experimentation. WMO/TD, no. 592. Strong, C., Fei-Fei Jin and Ghil, M. 1993. Intraseasonal variability in a barotropic model with seasonal forcing. J. Atmos. Sc i . 50 , 2965 – 2986 .
Search in Google Scholar Back to article
Wallace , J. M. and Gutzler , D. S . 1981 . Teleconnections in the geopotential height field during the northern hemisphere winter. Mon. Wea. Re v . 109 , 784 – 812 .
Search in Google Scholar Back to article
Weber , R. and Madden , R . 1993 . Evidence of traveling external Rossby waves in the ECMWF analyses. J. Atmos. Sc i . 50 , 2994 – 3007 .
Search in Google Scholar Back to article
Weicicmann , K. , Lussky , G. and Kutzbach , J. 1985. Interseasonal (30-60 day) fluctuations of outgoing longwave radiation and 250 mb streamfunction during northern winter . Mon. Wea. Rev . 113 , 941 – 961.
Search in Google Scholar Back to article

Articles in this issue

DOI: https://doi.org/10.3402/tellusa.v47i5.11548 | Journal eISSN: 3035-9554

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Language: English

Page range: 561 - 574

Submitted on: Sep 15, 1994

Accepted on: Feb 27, 1995

Published on: Jan 1, 1995

Published by: Stockholm University Press

In partnership with: Paradigm Publishing Services

© 1995 Juhani Rinne, Simo Järvenoja, published by Stockholm University Press
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 47 (1995): Issue 5