Reconstruction of soil water oxygen isotope values from tree ring cellulose and its implications for paleoclimate studies

We present here a rationale for estimation of soil water oxygen isotope values (δsw) from tree ring cellulose oxygen isotope data and examine, for the first time, its (δsw) efficacy as a tool to obtain paleoclimate information. We analyzed pre-dated tree ring cellulose samples collected from a site at Western Himalaya for oxygen isotopes, used similar dataset of overlapping time period from 12 different locations across the world, reconstructed δsw for 1901–2004 CE, compared the data with available observations and examined implications of this technique. Our study shows (a) good agreement in spatial ranges between observed and estimated δsw data suggesting its suitability for a representative parameter, and (b) reconstructed δsw largely depend on soil moisture content modulated by regional evaporation regimes. Considering a growing importance of measurement of recycled soil moisture and its ensuing role in rainfall amount, a method to reconstruct soil moisture isotope as presented in this work will enable application of land hydrological models to the past.