Sunday, January 26, 2014

New paper finds another amplification mechanism by which the Sun controls climate

A new paper published in Palaeogeography, Palaeoclimatology, Palaeoecology finds another solar amplification mechanism by which tiny changes in solar activity during 11-12 year solar cycles have a "strong" influence on the Indian Summer Monsoon [ISM]. The ISM in turn profoundly affects the south Asian climate, and interacts with other global atmospheric oscillations. 

The paper adds to hundreds of other peer-reviewed publications finding solar amplification mechanisms via effects on natural atmospheric and ocean oscillations such as the Southern Oscillation, North Atlantic Oscillation, Scandinavian Pattern, Quasi Biennial Oscillation (QBO), Indian Summer Monsoon, El Nino Southern Oscillation [ENSO], Pacific Decadal Oscillation, Madden-Julian Oscillation, and others. Other amplification mechanisms include via ozone and sunshine hours/clouds.

Spectral analysis of climate cycles in the climate proxy data shows >99% confidence of cycles lasting ~12 years [1 solar cycle] and ~33 years [3 solar cycles] 

Speleothem based 1000-year high resolution record of Indian monsoon variability during the last deglaciation

  • a CSIR-National Geophysical Research Institute, Hyderabad 500007, India
  • b High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan, ROC


First high resolution last deglacial ISM record from a South Indian speleothem
Decadal to multidecadal variability with abrupt changes in ISM activity
Strong solar and ocean–atmospheric control on Indian Summer Monsoon variability
South China caves influenced by Indian summer monsoon (ISM)
Timing of Termination 1a in Indian region and ISM relation with East Asian Monsoon


A high resolution record of the Indian summer monsoon (ISM) is generated using a δ18O time series from a stalagmite collected from the Valmiki cave in southern India. This record covers a time span of ~ 1000 years from 15,700 to 14,700 yr BP (before 1950 AD) with an average sampling resolution of ~ 5 years. High amplitude δ18O variation in this record reflects abrupt changes in ISM activity during the last deglaciation and suggest an age for the onset of Termination 1a (T1a) at ~ 14,800 yr BP in the Indian sub-continent. This record shows evidence for strong changes in tropical climate during the last deglaciation. Coincident variability in VSPM4 δ18O with speleothems from southern China during Termination 1a suggests that these caves reflect fluctuations in ISM activity. The variance in δ18O amplitude reveals significant multidecadal variability in ISM activity. Our record reveals intervals of strong monsoon activity during the later phase of Heinrich event 1 (H1) and shows synchronous multidecadal variability between ISM and East Asian monsoon (EAM). Spectral analysis of δ18O time series in VSPM4 reveals solar forcing and strong ocean–atmospheric circulation control on ISM dynamics during the studied time interval.

1 comment: