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.

西高止山脉 (WG) 是一个广阔的山地森林生态系统，以其生物多样性和特有性而闻名。WG 夏季季风降雨的年代际变率高于印度其他大部分地区。长达一个世纪的降雨观测的光谱和小波分析证实了 WG 降雨的显着年代际变化（在 90% 的置信水平上），与前半个世纪相比，近年来的幅度放大（约 1.5-2 倍）。WG 降雨量与印度（太平洋）海表温度（SST）的相关性分析表明，在 1901-1942 年（1943-1977 年和 1978-2010 年）期间存在显着关系。与年代际降雨变率相关的分析揭示了 1901-1942 年的动力过程和 1943-1977 年和 1978-2010 年的潮湿热力学过程的主导地位。