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Research Articles

Interannual variability of precipitation in Sri Lanka

Authors:

HKWI Jayawardene,

LK
About HKWI
Department of Physics, Faculty of Science, University of Colombo, Colombo 03.
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DR Jayewardene,

LK
About DR
Department of Mathematics, Faculty of Science, University of Colombo, Colombo 03.
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DUJ Sonnadara

LK
About DUJ

Department of Physics, Faculty of Science, University of Colombo, Colombo 03.

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Abstract

Two different spectral analysis methods, the multitaper method (MTM) and the maximum entropy method (MEM) were applied to investigate the presence of low-frequency periodicities in precipitation records of 14 climatological stations in Sri Lanka. The spectral analysis revealed statistically significant periodicities in the range of 2 – 3 year and 3 – 6 year periods in all parts of Sri Lanka irrespective of the climatic variability. The 2 – 3 year band corresponds to the Quasi-Biennial oscillation (QBO), while the 3 – 6 year band corresponds to the El-Nino/Southern oscillation (ENSO) higher and lower frequency bands. Cross spectrum analysis showed statistically significant (at 5 %) coherencies for the Indian Ocean dipole (IOD) and Southern oscillation index (SOI) in the 2 – 3 year band and the 3 – 6 year band, respectively for most of the regions. Thus, it is concluded that the IOD and SOI play important roles as modulators of precipitation in Sri Lanka.

J.Natn.Sci.Foundation Sri Lanka 2015 43 (1): 75-82

How to Cite: Jayawardene, H., Jayewardene, D. and Sonnadara, D., 2015. Interannual variability of precipitation in Sri Lanka. Journal of the National Science Foundation of Sri Lanka, 43(1), pp.75–82. DOI: http://doi.org/10.4038/jnsfsr.v43i1.7917
Published on 31 Mar 2015.
Peer Reviewed

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