Amount dependency of monsoon rainfall δ18O on multiple time scales: observations from south western India

The Intra‐Seasonal Oscillation of Precipitation δ18O Over the Asian Equatorial and Monsoon Regions

“…The ratio of stable isotope in modern precipitation is used for the interpretation and validation of climate and hydrological models, and paleoclimatic archives in tropical regions. The dominant factors influencing precipitation δ 18 O variation may vary from minutes (He, Goodkin, Kurita, et al., 2018) to inter‐annual time scales in Asia equatorial and monsoon regions (Cai & Tian, 2016; He, Goodkin, Jackisch, et al., 2018; Lekshmy et al., 2019), making this endeavor for such a purpose in argument. The MJO plays a critical role in connecting or bridging weather and climate, involved in scale interactions across a wide range of spectrum from the diurnal cycle to the inter‐annual variability (C. Zhang, 2013).…”

“…The criteria for defining significant intra‐seasonal oscillations of δ 18 O and OLR are determined from their respective means ( μ ) and one standard deviation (1 σ ) (beyond the range of μ ± 1 σ ) (Lekshmy et al., 2019). The PCx or PCy index is used for judging the intensity of BSISO or MJO.…”

“…Earlier studies have revealed that the 18 O depletion in monsoon rain is related to large‐scale organized convection (Lekshmy et al., 2014) and appeared to be linked with the monsoon intra‐seasonal variability or oscillation in addition to synoptic scale fluctuations (Chakraborty et al., 2016; Risi et al., 2008; Sengupta et al., 2020). It is reported that the Indian summer monsoon rainfall δ 18 O of southwestern India captures not only the local or upstream convective activities but reflects the rainfall pattern of a large domain (Lekshmy et al., 2019). The dilution of rainfall δ 18 O accompanying the increased proportion of large‐scale stratiform cloud cover of the deep convective system during the MJO onset period (Kurita et al., 2011).…”