Contribution of Recycled Moisture to Precipitation: A Modified D‐Excess‐Based Model

Defining moisture sources and evolution of precipitation is of significance for further exploration of complex hydro‐climatic interactions, especially under global warming with alternations of evapotranspiration capacity and precipitation moisture source structure. As a sensitive indicator, d‐excess has been widely used to quantify the proportion of recycled vapor to precipitation ( f re ). However, existing d‐excess‐based models ignore to take transpiration vapor into account and the calculated f re tends to be lower than the true value, thus underestimating the importance of recycled vapor in precipitation. Herein, the existing model was modified with transpiration vapor considered and applied in Guyuan, China located in a monsoon marginal zone with complex precipitation moisture sources. After modification, the estimated annual average f re was increased from 7.5% to 14.8%, well calibrating the existing model. This study highlights the contribution of transpiration vapor to precipitation and provides more information on the formation and evolution of precipitation to better serve future hydro‐climatic research.