Solar variability imprints on palaeoclimatic records from northwestern Himalaya

Understanding the impact of the Sun on climatic variability is crucial when analysing the current state of global warming and climate change. The present study is an initiative to elucidate the low-frequency (interannual and more extended period) variability in two paleoclimatic records obtained from Himalayan cedar and neoza pine tree rings from Lahaul, Himachal Pradesh, and Kishtwar, Jammu & Kashmir, for the time intervals of 1460–2008 CE and 1383–2017 CE, respectively. Time-series analysis was performed to re-examine the tree-ring chronologies using the wavelet transform. The strong interannual variability of a 2- to 4-year timescale was present throughout the record. There was a notable decadal fluctuation, which is ascribed to the well-known 11-year solar cycle. Long-term variability of nearly 30–35 years and 60 years was also present during specific time scales. The wavelet coherence between tree-ring chronologies and sunspot numbers was also investigated to assess time-varying correlations. The present investigation provides evidence of solar activity effects/modulation on tree-ring growth in the northwestern Indian Himalayan region. The results are in good agreement with studies based on tree-ring chronologies conducted in other regions of the world. This suggests a strong control of solar variability on climate in the western Himalaya, particularly with respect to precipitation, by the westerlies as well as the Indian summer monsoon.