Effects of intraseasonal variation of summer monsoon rainfall on stable isotope and growth rate of a stalagmite from northwestern Thailand

dc.contributor.authorBinggui Caien_US
dc.contributor.authorNathsuda Pumijumnongen_US
dc.contributor.authorMing Tanen_US
dc.contributor.authorChotika Muangsongen_US
dc.contributor.authorXinggong Kongen_US
dc.contributor.authorXiuyang Jiangen_US
dc.contributor.authorSulan Nanen_US
dc.contributor.otherInstitute of Geology and Geophysics Chinese Academy of Sciencesen_US
dc.contributor.otherNational Research Center of Geoanalysis Beijingen_US
dc.contributor.otherFaculty of Environment and Resource Studies, Mahidol Universityen_US
dc.contributor.otherNanjing Normal Universityen_US
dc.contributor.otherChinese Academy of Meteorological Sciencesen_US
dc.description.abstractAn annually laminated stalagmite from Namjang cave (194030N, 981212E), northwestern Thailand, has been analyzed to investigate the annual resolution climate signal persevered within its oxygen isotopic composition (δ<sup>18</sup>O) and growth rate parameters. The cave site is under the influence of Asian monsoon, and local rainfall shows noticeable variations through the monsoon season. Both δ<sup>18</sup>O and growth rate records, covering the last 105 years, exhibit persistent decadal-scale variability and can be compared with local instrumental data. Low δ<sup>18</sup>O values coincide with high growth rates in the specimen and correspond to higher relative amounts of rainfall in later monsoon season (August-October; hereinafter referred to as ASO rainfall) versus rainfall in early monsoon season (May-July; hereinafter referred to as MJJ rainfall). The strong correlation between the δ<sup>18</sup>O value and the 5 year averaged ratio of ASO to MJJ rainfall (r = -0.50, p < 0.001) indicates a significant imprint of intraseasonal variation of monsoonal rainfall on stalagmite δ <sup>18</sup>O. The close resemblance between the speleothem δ<sup>18</sup>O record and Western Pacific Warm Pool (WPWP) sea surface temperature (SST) implies that the WPWP may play an important role on the decadal variability of later monsoon rainfall in this region. Unique in its annual chronology, high-resolution δ<sup>18</sup>O, and direct comparison with instrumental data, our record shows for the first time that the climate in northwestern Thailand has undergone decadal-scale variability and speleothem δ<sup>18</sup>O is a robust proxy for regional monsoon intensity. Copyright © 2010 by the American Geophysical Union.en_US
dc.identifier.citationJournal of Geophysical Research Atmospheres. Vol.115, No.21 (2010)en_US
dc.rightsMahidol Universityen_US
dc.subjectAgricultural and Biological Sciencesen_US
dc.subjectEarth and Planetary Sciencesen_US
dc.subjectEnvironmental Scienceen_US
dc.subjectMaterials Scienceen_US
dc.subjectPhysics and Astronomyen_US
dc.titleEffects of intraseasonal variation of summer monsoon rainfall on stable isotope and growth rate of a stalagmite from northwestern Thailanden_US