Oscillatory behavior of monsoon rainfall over Sri Lanka during the late 19(th) and 20(th) centuries and its relationships to SSTs in the Indian Ocean and ENSO
2007 (English)In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 89, no 02-jan, 115-125 p.Article in journal (Refereed) Published
In this study, we have analyzed the temporal oscillations of precipitation in meso-scale zones of Sri Lanka to examine potential existence of periodic oscillatory behavior in rainfall. Only a few statistically significant cycles were identified: a 3.5-year cycle in most of central Sri Lanka during the January-March rainfall regime and a cycle of the same length in southwestern Sri Lanka during the October regime. A 2.1-year cycle marks the northeastern parts of Sri Lanka during the December/April contrast rainfall regime. This cycle is shown to be strongly related to Quasi-Biennial Oscillation. October and November rainfall are found to be coupled with ENSO fluctuations, and on average, more than 900mm more rainfall is observed per month over all stations during El Nifio than during La Nina years. Analysis of relationships between the observed meso-scale rainfall regions and the Sea Surface Temperatures (SSTs) in the Indian Ocean north of the Equator showed that the northern Indian Ocean can be divided into three particular regions based on similarity in the SST fluctuations: (a) a region with cool upwelling water, (b) non upwelling water, and (c) the Indian Ocean Warm Pool. We found that there are no statistically significant relationships between the observed SST regions in the Indian Ocean and the meso-scale precipitation patterns in Sri Lanka.
Place, publisher, year, edition, pages
2007. Vol. 89, no 02-jan, 115-125 p.
nino-southern oscillation, southwest monsoon, time-series, spectrum, fluctuations
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:su:diva-56252DOI: 10.1007/s00704-006-0225-9ISI: 000246845100011OAI: oai:DiVA.org:su-56252DiVA: diva2:411034
authorCount :62011-04-152011-04-122011-04-15Bibliographically approved