Continental water recycling and H2(18)-O concentrations

Using a General Circulation Model (GCM) fitted with tracer diagnostics, we examine how continental moisture recycling affects the stable water isotope content of precipitation, focusing on its contribution to the 'noise' in the well-established relationship between temperature and delta O-18. On a global basis, for temperatures between -30 and 15 C, continental recycling explains more than a third of the variability in annual delta O-18 that is not explained by temperature. Recycling appears almost as important as temperature in defining delta O-18 distributions during northern hemisphere summer.