Summary of Abstract Submission

Abstract Submission No. IO50-05-0005PresentationPoster

PAST INDIAN SUMMER MONSOON PRECIPITATION VARIABILITY VIS--VIS RECENT SOLAR MINIMA

Manish Tiwari*1, Siddhesh S. Nagoji1, Raja S. Ganeshram2

1 National Centre for Antarctic & Ocean Research, India
2 School of GeoSciences, Grant Institute, University of Edinburgh, UK

ABSTRACT :

Influence of solar activity on the Indian summer monsoon (ISM) precipitation on different timescales is an active area of research. It becomes more fascinating given that the slight variability in total solar irradiance (e.g., only 0.08 % over an 11-yr solar cycle) is proposed to cause large scale ocean-atmospheric changes via direct and indirect mechanisms. Most of the studies have looked at the ISM-solar activity relation on glacial-interglacial timescale for early Holocene and beyond. Additionally, those from the western Arabian Sea provide records of ISM wind intensity and not the ISM precipitation. A few high-resolution (centennial scale) studies from the eastern Arabian Sea have explored the correlation between the recent solar minima and the ISM precipitation but they are either too short or have not corrected for temperature effect on the oxygen isotopes of foraminifera. We have reconstructed a new centennial scale record of salinity related to ISM precipitation from the western coast of India since the mid-Holocene after correcting for the above mentioned temperature effect. This study identifies periods of aridity during the Little Ice Age (and a few centuries prior to it) and at 1300 yr BP, 2000 yr BP, and 4600 yr BP. The ISM precipitation declined in phase with the TSI during the recent periods of major TSI minima but it lagged the TSI beyond 1300 yr BP by a couple of hundred years confirmed through wavelet analysis and comparison with earlier studies.