Summary
It is believed that the large scale anomalies in the performance of the Indian summer monsoon are a part of the general circulation anomalies having periods larger than the four monsoon months. It may, therefore, be possible to link anomalies of the Indian summer monsoon with anomalies of the global flow pattern, a few months ahead. To get anomalies of global flow pattern, we need quantitative measures of normal global flow pattern. With this idea in view, the monthly northern hemispheric constant pressure charts prepared by Free University of Berlin have been subjected to spherical harmonic analysis form=0, 1, 2,..., 18 andn−m=0, 2, 4,..., 18. The features of normal contour patterns for the months of March to July are pesented in this report form=1, 2 andn−m=0,2 for standard isobaric levels 850, 700, 500, 300, 200 and 100mb. The veritcal and the horizontal tilts of wave numbers 1 and 2 are discussed in some detail.
Zusammenfassung
Großräumige Anomalien im Verhalten des indischen Sommermonsuns stehen höchstwahrscheinlich im Zusammenhang mit Anomalien der allgemeinen Zirkulation der Atmosphäre, die länger als die vier Sommermonsunmonate andauern. Es müßte daher möglich sein, Anomalien im indischen Sommermonsun mit globalen Strömungsverhältnissen etliche Monate vor dem Ausbruch des Monsuns in Zusammenhang zu bringen. Um Anomalien der globalen Strömungsverhältnisse abschätzen zu können, bedarf es einer quantitativen Abschätzung der mittleren Strömungsverhätlnisse. Zu diesem Zwecke wurden die monatlischen Mittelkarten konstanter Druckflächen, die von der Freien Universität Berlin zur Verfügung stehen, einer sphärischen harmonischen Analyse fürm=0, 1, 2,..., 18 undn−m=0, 2, 4,..., 18 unterzogen.
Die markanten Merkmale der mittleren Konturenverteilung für die Monate März bis Juli werden in diesem Bericht fürm=1, 2 undn−m=0, 2 und für die Standardisobarenflächen 850, 700, 500, 300, 200 und 100mb beschrieben. Die vertikalen und horizontalen Neigungen der Wellenzahlen 1 und 2 werden im Detail besprochen.
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Awade, S.T., Asnani, G.C. & Keshavamurty, R.N. Spherical harmonic analysis of the normal constant pressure charts in the northern hemisphere. Arch. Met. Geoph. Biokl. A. 24, 189–205 (1975). https://doi.org/10.1007/BF02245378
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DOI: https://doi.org/10.1007/BF02245378