Dynamical and moist thermodynamical processes associated with Western Ghats rainfall decadal variability

The Western Ghats (WG) is a vast montane forest ecosystem known for its biodiversity and endemism. The decadal variability of WG summer monsoon rainfall is higher than most of the other regions of India. Spectrum and wavelet analysis of century-long rainfall observation confirm significant decadal variability (at 90% confidence level) in WG rainfall, with amplification of magnitude (about 1.5-2 times) in the recent years compared to the previous half-century. Correlation analysis of WG rainfall with Indian (Pacific) Ocean sea surface temperature (SST) shows a significant relationship during 1901-1942 (1943-1977 and 1978-2010). The analysis associated with decadal rainfall variability reveals the dominance of dynamical processes during 1901-1942 and moist thermodynamical processes during 1943-1977 and 1978-2010. The study concludes that decadal variability of WG rainfall is robust and the forcing mechanisms are essentially maintained by the Indian and Pacific Oceans variability, adding value in developing decadal prediction systems and may also contribute towards understanding the evolution of WG ecosystem.

Automated summary

This study found that there is significant decadal variability in summer monsoon rainfall in the Western Ghats, with increasing magnitude in recent years. The Indian and Pacific Oceans play a crucial role in influencing the rainfall patterns in this region. These findings are valuable for developing decadal prediction systems and understanding the evolution of the Western Ghats ecosystem.