Origin of a trend in ECMWF wind analysis and its objective removal

Goswami, BN and Annamalai, H (1996) Origin of a trend in ECMWF wind analysis and its objective removal. In: Proceedings of the Indian Academy of Sciences - Earth & Planetary Sciences, 105 (2). pp. 101-117.

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Abstract

The suitability of the European Centre for Medium Range Weather Forecasting (ECMWF) operational wind analysis for the period 1980-1991 for studying interannual variability is examined. The changes in the model and the analysis procedure are shown to give rise to a systematic and significant trend in the large scale circulation features. A new method of removing the systematic errors at all levels is presented using multivariate EOF analysis. Objectively detrended analysis of the three-dimensional wind field agrees well with independent Florida State University (FSU) wind analysis at the surface. It is shown that the interannual variations in the detrended surface analysis agree well in amplitude as well as spatial patterns with those of the FSU analysis. Therefore, the detrended analyses at other levels as well are expected to be useful for studies of variability and predictability at interannual time scales. It is demonstrated that this trend in the wind field is due to the shift in the climatologies from the period 1980-1985 to the period 1986-1991.

Item Type:	Journal Article
Publication:	Proceedings of the Indian Academy of Sciences - Earth & Planetary Sciences
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	ECMWF objective analysis;interannual variability;combined EOF analysis;removal of unphysical trend.
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	10 May 2011 06:12
Last Modified:	10 May 2011 06:12
URI:	http://eprints.iisc.ac.in/id/eprint/37451

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