Climatic periodicities recorded in lake sediment magnetic susceptibility data: Further evidence for solar forcing on Indian summer monsoon

Anish Kumar Warrier, Kizhur Sandeep, Rajasekharaiah Shankar

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The Indian summer monsoon exhibits considerable spatio-temporal variability. It is therefore important to understand its dynamics and the inherent periodicities. In this study, we have performed spectral and wavelet analyses of magnetic susceptibility data for sediments from Thimmannanayakanakere (TK)–a small lake in southern India. The main objective of this investigation is to identify and explain the possible origin of the prominent periodicities present in the magnetic susceptibility data. Significant periodicities in the TK χlf data are centered at 906, 232, 147, 128, 96, 61, 54 and 44 years, which might have a solar origin. The wavelet power spectrum of the raw and detrended χlf data confirms the findings of spectral analysis and also provides temporal variations of the significant cyclicities during the past 3700 cal. years B.P. Positive correlation is documented between sunspot activity and TK χlf data; cross-spectral analysis of the reconstructed sunspot data and TK χlf data suggest that there is a strong coherence between the two datasets as significant periodicities are documented in both. There is a good match between the TK χlf and the reconstructed total solar irradiance data for the past 1200 years. However, an out-of-phase relationship is documented at certain time-intervals, which may be attributed to uncertainties in the age-depth model. The results obtained from this study show that solar variations are the main controlling factor of the southwest monsoon and, like other archives from different regions in India, the TK lake sediments have also recorded these solar signatures.

Original languageEnglish
Pages (from-to)1349-1355
Number of pages7
JournalGeoscience Frontiers
Volume8
Issue number6
DOIs
Publication statusPublished - 01-11-2017

All Science Journal Classification (ASJC) codes

  • Earth and Planetary Sciences(all)

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