How meteorological and cloud processes affect water isotopes in a tropical rain shadow region?

Stable water isotopes can be used as natural tracers of various physical processes in the atmospheric water cycle. The isotopic signal is modulated by several meteorological and cloud microphysical processes such as moisture recycling, advection, condensation, evaporation, etc. The interaction of these processes with water isotopes are often complex in tropical orographic regions especially in the lee side of the mountains which are, in general,  rain shadow regions. Disentangling the roles of these process in the water isotope variability is very important considering these regions host a gamut of natural archieves from which decadal to centennial scale climate have been reconstructed earlier. Towards this, the current study presents daily rain and ground level vapour isotope observations in a tropical Indian rain-shadow region.The analyses shows that mesoscale convections affect both water isotope values significantly. A considerable isotopic exchange between rain and vapour is also noted in the sub cloud layer suggesting a strong control of sub cloud processes in the isotope values. Using an 1-D model, the role of all these process in the isotope values are further evaluated.