Chan, WP; Yuan, HW; Huang, CY; Wang, CH; Lin, SD; Lo, YC; Huang, BW; Hatch, KA; Shiu, HJ; You, CF; Chang, YM; Shen, SF (2012). Regional Scale High Resolution delta O-18 Prediction in Precipitation Using MODIS EVI. PLOS ONE, 7(9), e45496.
The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, paleoclimatology, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict delta O-18 in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated delta O-18 are highly correlated and thus the EVI is a good predictor of precipitated delta O-18. We then test the predictability of our EVI-delta O-18 model and demonstrate that our approach can provide high accuracy with fine spatial (250x250 m) and temporal (16 days) scale delta O-18 predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and delta O-18 in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape.